[Federal Register Volume 72, Number 15 (Wednesday, January 24, 2007)]
[Proposed Rules]
[Pages 3200-3344]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 07-110]



[[Page 3199]]

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Part II





Environmental Protection Agency





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40 CFR Part 86



Control of Air Pollution From New Motor Vehicles and New Motor Vehicle 
Engines--Heavy-Duty Vehicle and Engine Standards; Onboard Diagnostic 
Requirements; Proposed Rule

  Federal Register / Vol. 72, No. 15 / Wednesday, January 24, 2007 / 
Proposed Rules  

[[Page 3200]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 86

[OAR-2005-0047; FRL-8256-9]
RIN 2060-AL92


Control of Air Pollution From New Motor Vehicles and New Motor 
Vehicle Engines; Regulations Requiring Onboard Diagnostic Systems on 
2010 and Later Heavy-Duty Engines Used in Highway Applications Over 
14,000 Pounds; Revisions to Onboard Diagnostic Requirements for Diesel 
Highway Heavy-Duty Vehicles Under 14,000 Pounds

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of proposed rulemaking.

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SUMMARY: In 2001, EPA finalized a new, major program for highway heavy-
duty engines. That program, the Clean Diesel Trucks and Buses program, 
will result in the introduction of advanced emissions control systems 
such as catalyzed diesel particulate filters (DPF) and catalysts 
capable of reducing harmful nitrogen oxide (NOX) emissions. 
This proposal would require that these advanced emissions control 
systems be monitored for malfunctions via an onboard diagnostic system 
(OBD), similar to those systems that have been required on passenger 
cars since the mid-1990s. This proposal would require manufacturers to 
install OBD systems that monitor the functioning of emission control 
components and alert the vehicle operator to any detected need for 
emission related repair. This proposal would also require that 
manufacturers make available to the service and repair industry 
information necessary to perform repair and maintenance service on OBD 
systems and other emission related engine components. Lastly, this 
proposal would revise certain existing OBD requirements for diesel 
engines used in heavy-duty vehicles under 14,000 pounds.

DATES: If we do not receive a request for a public hearing, written 
comments are due March 26, 2007. Requests for a public hearing must be 
received by February 8, 2007. If we do receive a request for a public 
hearing, we will publish a notice in the Federal Register and on the 
Web at http://www.epa.gov/obd/regtech/heavy.htm containing details 
regarding the location, date, and time of the public hearing. In that 
case, the public comment period would close 30 days after the public 
hearing. Under the Paperwork Reduction Act, comments on the information 
collection provisions must be received by OMB on or before February 23, 
2007.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2005-0047, by one of the following methods:
     http://www.regulations.gov: Follow the on-line 
instructions for submitting comments.
     Mail: Onboard Diagnostic (OBD) Systems on 2010 and Later 
Heavy-Duty Highway Vehicles and Engines, Environmental Protection 
Agency, Mailcode: 6102T, 1200 Pennsylvania Ave., NW., Washington, DC, 
20460, Attention Docket ID No. EPA-HQ-OAR-2005-0047. In addition, 
please mail a copy of your comments on the information collection 
provisions to the Office of Information and Regulatory Affairs, Office 
of Management and Budget (OMB), Attn: Desk Officer for EPA, 725 17th 
St. NW., Washington, DC 20503.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2005-0047. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
http://www.regulations.gov, including any personal information 
provided, unless the comment includes information claimed to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Do not submit information that you 
consider to be CBI or otherwise protected through http://www.regulations.gov or e-mail. The http://www.regulations.gov Web site 
is an ``anonymous access'' system, which means EPA will not know your 
identity or contact information unless you provide it in the body of 
your comment. If you send an e-mail comment directly to EPA without 
going through http://www.regulations.gov your e-mail address will be 
automatically captured and included as part of the comment that is 
placed in the public docket and made available on the Internet. If you 
submit an electronic comment, EPA recommends that you include your name 
and other contact information in the body of your comment and with any 
disk or CD-ROM you submit. If EPA cannot read your comment due to 
technical difficulties and cannot contact you for clarification, EPA 
may not be able to consider your comment. Electronic files should avoid 
the use of special characters, any form of encryption, and be free of 
any defects or viruses.
    Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in http://www.regulations.gov or in hard copy at the Air Docket, EPA/
DC, EPA West, Room B102, 1301 Constitution Ave., NW., Washington, DC. 
The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday 
through Friday, excluding legal holidays. The telephone number for the 
Public Reading Room is (202) 566-1744, and the telephone number for the 
Air Docket is (202) 566-1742.


    Note: The EPA Docket Center suffered damage due to flooding 
during the last week of June 2006. The Docket Center is continuing 
to operate. However, during the cleanup, there will be temporary 
changes to Docket Center telephone numbers, addresses, and hours of 
operation for people who wish to make hand deliveries or visit the 
Public Reading Room to view documents. Consult EPA's Federal 
Register notice at 71 FR 38147 (July 5, 2006) or the EPA Web site at 
http://www.epa.gov/epahome/dockets.htm for current information on 
docket operations, locations and telephone numbers. The Docket 
Center's mailing address for U.S. mail and the procedure for 
submitting comments to www.regulations.gov are not affected by the 
flooding and will remain the same.


FOR FURTHER INFORMATION CONTACT: U.S. EPA, National Vehicle and Fuel 
Emissions Laboratory, Assessment and Standards Division, 2000 
Traverwood Drive, Ann Arbor, MI 48105; telephone (734) 214-4405, fax 
(734) 214-4816, email [email protected].

SUPPLEMENTARY INFORMATION:

Regulated Entities

    This action will affect you if you produce or import new heavy-duty 
engines which are intended for use in highway vehicles such as trucks 
and buses, or produce or import such highway vehicles, or convert 
heavy-duty vehicles or heavy-duty engines used in highway vehicles to 
use alternative fuels.
    The following table gives some examples of entities that may have 
to follow the regulations. But because these are only examples, you 
should carefully examine the regulations in 40 CFR part 86. If you have 
questions, call the person listed in the FOR FURTHER INFORMATION 
CONTACT section of this preamble:

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                                                                              Examples of potentially regulated
                  Category                   NAICS Codes\a\   SIC Codes\b\                 entities
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Industry...................................          336111            3711  Motor Vehicle Manufacturers; Engine
                                                     336112                   and Truck Manufacturers.
                                                     336120
Industry...................................          811112            7533  Commercial Importers of Vehicles
                                                     811198            7549   and Vehicle Components.
                                                     541514            8742
Industry...................................          336111            3592  Alternative fuel vehicle
                                                                              converters.
                                                     336312            3714
                                                     422720            5172
                                                     454312            5984
                                                     811198            7549
                                                     541514            8742
                                                     541690           8931
----------------------------------------------------------------------------------------------------------------
\a\North American Industry Classification Systems (NAICS).
\b\Standard Industrial Classification (SIC) system code.

What Should I Consider as I Prepare My Comments for EPA?

    Submitting CBI. Do not submit this information to EPA through 
www.regulations.gov or e-mail. Clearly mark the part or all of the 
information that you claim to be CBI. For CBI information in a disk or 
CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as 
CBI and then identify electronically within the disk or CD ROM the 
specific information that is claimed as CBI). In addition to one 
complete version of the comment that includes information claimed as 
CBI, a copy of the comment that does not contain the information 
claimed as CBI must be submitted for inclusion in the public docket. 
Information so marked will not be disclosed except in accordance with 
procedures set forth in 40 CFR part 2.
    Tips for Preparing Your Comments. When submitting comments, 
remember to:
     Identify the rulemaking by docket number and other 
identifying information (subject heading, Federal Register date and 
page number).
     Follow directions--The agency may ask you to respond to 
specific questions or organize comments by referencing a Code of 
Federal Regulations (CFR) part or section number.
     Explain why you agree or disagree; suggest alternatives 
and substitute language for your requested changes.
     Describe any assumptions and provide any technical 
information and/or data that you used.
     If you estimate potential costs or burdens, explain how 
you arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
     Provide specific examples to illustrate your concerns, and 
suggest alternatives.
     Explain your views as clearly as possible, avoiding the 
use of profanity or personal threats.
     Make sure to submit your comments by the comment period 
deadline identified.

Outline of this Preamble

I. Overview
    A. Background
    B. What Is EPA Proposing?
    1. OBD Requirements for Engines Used in Highway Vehicles Over 
14,000 Pounds GVWR
    2. Requirements That Service Information Be Made Available
    3. OBD Requirements for Diesel Heavy-Duty Vehicles and Engines 
Used in Vehicles Under 14,000 Pounds
    C. Why Is EPA Making This Proposal?
    1. Highway Engines and Vehicles Contribute to Serious Air 
Pollution Problems
    2. Emissions Control of Highway Engines and Vehicles Depends on 
Properly Operating Emissions Control Systems
    3. Basis for Action Under the Clean Air Act
    D. How Has EPA Chosen the Level of the Proposed Emissions 
Thresholds?
    E. World Wide Harmonized OBD (WWH-OBD)
    F. Onboard Diagnostics for Diesel Engines Used in Nonroad Land-
Based Equipment
    1. What Is the Baseline Nonroad OBD System?
    2. What Is The Appropriate Level of OBD Monitoring for Nonroad 
Diesel Engines?
    3. What Should the OBD Standardization Features Be?
    4. What Are the Prospects and/or Desires for International 
Harmonization of Nonroad OBD?
II. What Are the Proposed OBD Requirements and When Would They Be 
Implemented?
    A. General OBD System Requirements
    1. The OBD System
    2. Malfunction Indicator Light (MIL) and Diagnostic Trouble 
Codes (DTC)
    3. Monitoring Conditions
    4. Determining the Proper OBD Malfunction Criteria
    B. Monitoring Requirements and Timelines for Diesel-Fueled/
Compression-Ignition Engines
    1. Fuel System Monitoring
    2. Engine Misfire Monitoring
    3. Exhaust Gas Recirculation (EGR) System Monitoring
    4. Turbo Boost Control System Monitoring
    5. Non-Methane Hydrocarbon (NMHC) Converting Catalyst Monitoring
    6. Selective Catalytic Reduction (SCR) and Lean NOX 
Catalyst Monitoring
    7. NOX Adsorber System Monitoring
    8. Diesel Particulate Filter (DPF) System Monitoring
    9. Exhaust Gas Sensor Monitoring
    C. Monitoring Requirements and Timelines for Gasoline/Spark-
Ignition Engines
    1. Fuel System Monitoring
    2. Engine Misfire Monitoring
    3. Exhaust Gas Recirculation (EGR) Monitoring
    4. Cold Start Emission Reduction Strategy Monitoring
    5. Secondary Air System Monitoring
    6. Catalytic Converter Monitoring
    7. Evaporative Emission Control System Monitoring
    8. Exhaust Gas Sensor Monitoring
    D. Monitoring Requirements and Timelines for Other Diesel and 
Gasoline Systems
    1. Variable Valve Timing and/or Control (VVT) System Monitoring
    2. Engine Cooling System Monitoring
    3. Crankcase Ventilation System Monitoring
    4. Comprehensive Component Monitors
    5. Other Emissions Control System Monitoring
    6. Exceptions to Monitoring Requirements
    E. A Standardized Method To Measure Real World Monitoring 
Performance
    1. Description of Software Counters To Track Real World 
Performance
    2. Proposed Performance Tracking Requirements
    F. Standardization Requirements
    1. Reference Documents
    2. Diagnostic Connector Requirements
    3. Communications to a Scan Tool
    4. Required Emissions Related Functions
    5. In-Use Performance Ratio Tracking Requirements
    6. Exceptions to Standardization Requirements
    G. Implementation Schedule, In-Use Liability, and In-Use 
Enforcement
    1. Implementation Schedule and In-Use Liability Provisions
    2. In-Use Enforcement
    H. Proposed Changes to the Existing 8,500 to 14,000 Pound Diesel 
OBD Requirements

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    1. Selective Catalytic Reduction and Lean NOX 
Catalyst Monitoring
    2. NOX Adsorber System Monitoring
    3. Diesel Particulate Filter System Monitoring
    4. NMHC Converting Catalyst Monitoring
    5. Other Monitors
    6. CARB OBDII Compliance Option and Deficiencies
    I. How Do the Proposed Requirements Compare to California's?
III. Are the Proposed Monitoring Requirements Feasible?
    A. Feasibility of the Monitoring Requirements for Diesel/
Compression-Ignition Engines
    1. Fuel System Monitoring
    2. Engine Misfire Monitoring
    3. Exhaust Gas Recirculation (EGR) Monitoring
    4. Turbo Boost Control System Monitoring
    5. Non-Methane Hydrocarbon (NMHC) Converting Catalyst Monitoring
    6. Selective Catalytic Reduction (SCR) and NOX 
Conversion Catalyst Monitoring
    7. NOX Adsorber Monitoring
    8. Diesel Particulate Filter (DPF) Monitoring
    9. Exhaust Gas Sensor Monitoring
    B. Feasibility of the Monitoring Requirements for Gasoline/
Spark-Ignition Engines
    1. Fuel System Monitoring
    2. Engine Misfire Monitoring
    3. Exhaust Gas Recirculation (EGR) Monitoring
    4. Cold Start Emission Reduction Strategy Monitoring
    5. Secondary Air System Monitoring
    6. Catalytic Converter Monitoring
    7. Evaporative System Monitoring
    8. Exhaust Gas Sensor Monitoring
    C. Feasibility of the Monitoring Requirements for Other Diesel 
and Gasoline Systems
    1. Variable Valve Timing and/or Control (VVT) System Monitoring
    2. Engine Cooling System Monitoring
    3. Crankcase Ventilation System Monitoring
    4. Comprehensive Component Monitoring
IV. What Are the Service Information Availability Requirements?
    A. What Is the Important Background Information for the Proposed 
Service Information Provisions?
    B. How Do the Below 14,000 Pound and Above 14,000 Pounds 
Aftermarket Service Industry Compare?
    C. What Provisions Are Being Proposed for Service Information 
Availability?
    1. What Information Is Proposed To Be Made Available by OEMs?
    2. What Are the Proposed Requirements for Web-Based Delivery of 
the Required Information?
    3. What Provisions Are Being Proposed for Service Information 
for Third Party Information Providers?
    4. What Requirements Are Being Proposed for the Availability of 
Training Information?
    5. What Requirements Are Being Proposed for Reprogramming of 
Vehicles?
    6. What Requirements Are Being Proposed for the Availability of 
Enhanced Information for Scan Tools for Equipment and Tool 
Companies?
    7. What Requirements Are Being Proposed for the Availability of 
OEM--Specific Diagnostic Scan Tools and Other Special Tools?
    8. Which Reference Materials Are Being Proposed for 
Incorporation by Reference?
V. What Are the Emissions Reductions Associated With the Proposed 
OBD Requirements?
VI. What Are the Costs Associated With the Proposed OBD 
Requirements?
    A. Variable Costs for Engines Used in Vehicles Over 14,000 
Pounds
    B. Fixed Costs for Engines Used in Vehicles Over 14,000 Pounds
    C. Total Costs for Engines Used in Vehicles Over 14,000 Pounds
    D. Costs for Diesel Heavy-Duty Vehicles and Engines Used in 
Heavy-Duty Vehicles Under 14,000 Pounds
VII. What are the Updated Annual Costs and Costs per Ton Associated 
With the 2007/2010 Heavy-Duty Highway Program?
    A. Updated 2007 Heavy-Duty Highway Rule Costs Including OBD
    B. Updated 2007 Heavy-Duty Highway Rule Costs Per Ton Including 
OBD
VIII. What Are the Requirements for Engine Manufacturers?
    A. Documentation Requirements
    B. Catalyst Aging Procedures
    C. Demonstration Testing
    1. Selection of Test Engines
    2. Required Testing
    3. Testing Protocol
    4. Evaluation Protocol
    5. Confirmatory Testing
    D. Deficiencies
    E. Production Evaluation Testing
    1. Verification of Standardization Requirements
    2. Verification of Monitoring Requirements
    3. Verification of In-Use Monitoring Performance Ratios
IX. What Are the Issues Concerning Inspection and Maintenance 
Programs?
    A. Current Heavy-Duty I/M Programs
    B. Challenges for Heavy-Duty I/M
    C. Heavy-Duty OBD and I/M
X. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act (RFA), as Amended by the Small 
Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 
U.S.C. 601 et. seq.
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect 
Energy Supply, Distribution, or Use
    I. National Technology Transfer Advancement Act
XI. Statutory Provisions and Legal Authority

I. Overview

A. Background

    Section 202(m) of the CAA, 42 U.S.C. 7521(m), directs EPA to 
promulgate regulations requiring 1994 and later model year light-duty 
vehicles (LDVs) and light-duty trucks (LDTs) to contain an OBD system 
that monitors emission-related components for malfunctions or 
deterioration ``which could cause or result in failure of the vehicles 
to comply with emission standards established'' for such vehicles. 
Section 202(m) also states that, ``The Administrator may, in the 
Administrator's discretion, promulgate regulations requiring 
manufacturers to install such onboard diagnostic systems on heavy-duty 
vehicles and engines.''
    On February 19, 1993, we published a final rule requiring 
manufacturers of light-duty applications to install such OBD systems on 
their vehicles beginning with the 1994 model year (58 FR 9468). The OBD 
systems must monitor emission control components for any malfunction or 
deterioration that could cause exceedance of certain emission 
thresholds. The regulation also required that the driver be notified of 
any need for repair via a dashboard light, or malfunction indicator 
light (MIL), when the diagnostic system detected a problem. We also 
allowed optional compliance with California's second phase OBD 
requirements, referred to as OBDII (13 CCR 1968.1), for purposes of 
satisfying the EPA OBD requirements. Since publishing the 1993 OBD 
final rule, EPA has made several revisions to the OBD requirements, 
most of which served to align the EPA OBD requirements with revisions 
to the California OBDII requirements (13 CCR 1968.2).
    On August 9, 1995, EPA published a final rulemaking that set forth 
service information regulations for light-duty vehicles and light-duty 
trucks (60 FR 40474). These regulations, in part, required each 
Original Equipment Manufacturer (OEM) to do the following: (1) List all 
of its emission-related service and repair information on a Web site 
called FedWorld (including the cost of each item and where it could be 
purchased); (2) either provide enhanced information to equipment and 
tool companies or make its OEM-specific diagnostic tool available for 
purchase by aftermarket technicians, and (3) make reprogramming 
capability available to independent service and repair professionals if 
its franchised dealerships had such capability. These requirements are 
intended to ensure that aftermarket service and repair facilities

[[Page 3203]]

have access to the same emission-related service information, in the 
same or similar manner, as that provided by OEMs to their franchised 
dealerships. These service information availability requirements have 
been revised since that first final rule in response to changing 
technology among other reasons. (68 FR 38428)
    In October of 2000, we published a final rule requiring OBD systems 
on heavy-duty vehicles and engines up to 14,000 pounds GVWR (65 FR 
59896). In that rule, we expressed our intention of developing OBD 
requirements in a future rule for vehicles and engines used in vehicles 
over 14,000 pounds. We expressed this same intention in our 2007HD 
highway final rule (66 FR 5002) which established new heavy-duty 
highway emissions standards for 2007 and later model year engines. In 
June of 2003, we published a final rule extending service information 
availability requirements to heavy-duty vehicles and engines weighing 
up to 14,000 pounds GVWR. We declined extending these requirements to 
engines above 14,000 pounds GVWR at least until such engines are 
subject to OBD requirements.
    On January 18, 2001, EPA established a comprehensive national 
control program--the Clean Diesel Truck and Bus program--that regulates 
the heavy-duty vehicle and its fuel as a single system. (66 FR 5002) As 
part of this program, new emission standards will begin to take effect 
in model year 2007 and will apply to heavy-duty highway engines and 
vehicles. These standards are based on the use of high-efficiency 
catalytic exhaust emission control devices or comparably effective 
advanced technologies. Because these devices are damaged by sulfur, the 
regulation also requires the level of sulfur in highway diesel fuel be 
reduced by 97 percent.\1\
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    \1\ Note that the 2007HD highway rule contained new emissions 
standards for gasoline engines as well as diesel engines.
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    Today's action proposes new OBD requirements for highway engines 
used in vehicles greater than 14,000 pounds. Today's action also 
proposes new availability requirements for emission-related service 
information that will make this information more widely available to 
the industry servicing vehicles over 14,000 pounds.
    In addition to these proposed requirements and changes, we are 
seeking comment on possible future regulations that would require OBD 
systems on heavy-duty diesel engines used in nonroad equipment. Diesel 
engines used in nonroad equipment are, like highway engines, a major 
source of NOX and particulate matter (PM) emissions, and the 
diesel engines used in nonroad equipment are essentially the same as 
those used in heavy-duty highway trucks. Further, new regulations 
applicable to nonroad diesel engines will result in the introduction of 
advanced emissions control systems like those expected for highway 
diesel engines. (69 FR 38958) Therefore, having OBD systems and OBD 
regulations for nonroad engines seems to be a natural progression from 
the proposed requirements for heavy-duty highway engines. We discuss 
this issue in greater detail in section I of this preamble with the 
goal of soliciting public comment regarding how we should proceed with 
respect to nonroad OBD.

B. What Is EPA Proposing?

1. OBD Requirements for Engines Used in Highway Vehicles Over 14,000 
Pounds GVWR
    We believe that OBD requirements should be extended to include over 
14,000 pound heavy-duty vehicles and engines for many reasons. In the 
past, heavy-duty diesel engines have relied primarily on in-cylinder 
modifications to meet emission standards. For example, emission 
standards have been met through changes in fuel timing, piston design, 
combustion chamber design, charge air cooling, use of four valves per 
cylinder rather than two valves, and piston ring pack design and 
location improvements. In contrast, the 2004 and 2007 emission 
standards represent a different sort of technological challenge that 
are being met with the addition of exhaust gas recirculation (EGR) 
systems and the addition of exhaust aftertreatment devices such as 
diesel particulate filters (DPF), sometimes called PM traps, and 
NOX catalysts. Such ``add on'' devices can experience 
deterioration and malfunction that, unlike the engine design elements 
listed earlier, may go unnoticed by the driver. Because deterioration 
and malfunction of these devices can go unnoticed by the driver, and 
because their primary purpose is emissions control, and because the 
level of emission control is on the order of 50 to 99 percent, some 
form of diagnosis and malfunction detection is crucial. We believe that 
such detection can be effectively achieved by employing a well designed 
OBD system.
    The same is true for gasoline heavy-duty vehicles and engines. 
While emission control is managed with both engine design elements and 
aftertreatment devices, the catalytic converter is the primary emission 
control feature accounting for over 95 percent of the emission control. 
We believe that monitoring the emission control system for proper 
operation is critical to ensure that new vehicles and engines certified 
to the very low emission standards set in recent years continue to meet 
those standards throughout their full useful life.
    Further, the industry trend is clearly toward increasing use of 
computer and electronic controls for both engine and powertrain 
management, and for emission control. In fact, the heavy-duty industry 
has already gone a long way, absent any government regulation, to 
standardize computer communication protocols.\2\ Computer and 
electronic control systems, as opposed to mechanical systems, provide 
improvements in many areas including, but not limited to, improved 
precision and control, reduced weight, and lower cost. However, 
electronic and computer controls also create increased difficulty in 
diagnosing and repairing the malfunctions that inevitably occur in any 
engine or powertrain system. Today's proposed OBD requirements would 
build on the efforts already undertaken by the industry to ensure that 
key emissions related components will be monitored in future heavy-duty 
vehicles and engines and that the diagnosis and repair of those 
components will be as efficient and cost effective as possible.
---------------------------------------------------------------------------

    \2\ See ``On-Board Diagnostics, A Heavy-Duty Perspective,'' SAE 
951947; ``Recommended Practice for a Serial Control and 
Communications Vehicle Network,'' SAE J1939 which may be obtained 
from Society of Automotive Engineers International, 400 Commonwealth 
Dr., Warrendale, PA, 15096-0001; and ``Road Vehicles-Diagnostics on 
Controller Area Network (CAN)--Part 4: Requirements for emission-
related systems,'' ISO 15765-4:2001 which may be obtained from the 
International Organization for Standardization, Case Postale 56, CH-
1211 Geneva 20, Switzerland.
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    Lastly, heavy-duty engines and, in particular, diesel engines tend 
to have very long useful lives. With age comes deterioration and a 
tendency toward increasing emissions. With the OBD systems proposed 
today, we expect that these engines will continue to be properly 
maintained and therefore will continue to emit at low emissions levels 
even after accumulating hundreds of thousands and even a million miles.
    For the reasons laid out above, most manufacturers of vehicles, 
trucks, and engines have incorporated some type of OBD system into 
their products that are capable of identifying when certain types of 
malfunctions occur, and in what systems. In the heavy-duty industry, 
those OBD systems traditionally have been geared toward

[[Page 3204]]

detecting malfunctions causing drivability and/or fuel economy related 
problems. Without specific requirements for manufacturers to include 
OBD mechanisms to detect emission-related problems, those types of 
malfunctions that could result in high emissions without a 
corresponding adverse drivability or fuel economy impact could go 
unnoticed by both the driver and the repair technician. The resulting 
increase in emissions and detrimental impact on air quality could be 
avoided by incorporating an OBD system capable of detecting emission 
control system malfunctions.
2. Requirements That Service Information Be Made Available
    We are proposing that makers of engines that go into vehicles over 
14,000 pounds make available to any person engaged in repair or service 
all information necessary to make use of the OBD systems and for making 
emission-related repairs, including any emissions-related information 
that is provided by the OEM to franchised dealers. This information 
includes, but is not limited to, manuals, technical service bulletins 
(TSBs), a general description of the operation of each OBD monitor, 
etc. We discuss the proposed requirements further in section IV of this 
preamble.
    The proposed requirements are similar to those required currently 
for all 1996 and newer light-duty vehicles and light-duty trucks and 
2005 and newer heavy-duty applications up to 14,000 pounds. While EPA 
understands that there may be some differences between aftermarket 
service for the under 14,000 pound and over 14,000 pound applications, 
we believe that any such differences would not substantially affect the 
implementation of such requirements and that, therefore, it is 
reasonable to use EPA's existing service information regulations as a 
basis for proposing service information requirements for the over 
14,000 pound arena. See section IV for a complete discussion of the 
service information provisions being proposed for the availability of 
over 14,000 pound service information.
    Note that information for making emission-related repairs does not 
include information used to design and manufacture parts, but it may 
include OEM changes to internal calibrations and other indirect 
information, as discussed in section IV.
3. OBD Requirements for Diesel Heavy-Duty Vehicles and Engines Used in 
Vehicles Under 14,000 Pounds
    We are also proposing some changes to the existing diesel OBD 
requirements for heavy-duty applications under 14,000 pounds (i.e., 
8,500 to 14,000 pounds). Some of these changes are being proposed for 
the 2007 and later model years (i.e., for immediate implementation) 
because we believe that some of the requirements that we currently have 
in place for 8,500 to 14,000 pound applications cannot be met by 
diesels without granting widespread deficiencies to industry. Other 
changes are being proposed for the 2010 and later model years since 
they represent an increase in the stringency of our current OBD 
requirements and, therefore, some leadtime is necessary for 
manufacturers to comply. All of the changes being proposed for 8,500 to 
14,000 pound diesel applications would result in OBD emissions 
thresholds identical, for all practical purposes, to the OBD thresholds 
being proposed for over 14,000 pound applications.

C. Why Is EPA Making This Proposal?

1. Highway Engines and Vehicles Contribute to Serious Air Pollution 
Problems
    The pollution emitted by heavy-duty highway engines contributes 
greatly to our nation's continuing air quality problems. Our 2007HD 
highway rule was designed to address these serious air quality 
problems. These problems include premature mortality, aggravation of 
respiratory and cardiovascular disease, aggravation of existing asthma, 
acute respiratory symptoms, chronic bronchitis, and decreased lung 
function. Numerous studies also link diesel exhaust to increased 
incidence of lung cancer. We believe that diesel exhaust is likely to 
be carcinogenic to humans by inhalation and that this cancer hazard 
exists for occupational and environmental levels of exposure.
    Our 2007HD highway rule will regulate the heavy-duty vehicle and 
its fuel as a single system. As part of this program, new emission 
standards will begin to take effect in model year 2007 and phase-in 
through model year 2010, and will apply to heavy-duty highway engines 
and vehicles. These standards are based on the use of high-efficiency 
catalytic exhaust emission control devices or comparably effective 
advanced technologies and a cap on the allowable sulfur content in both 
diesel fuel and gasoline.
    In the 2007HD highway final rule, we estimated that, by 2007, 
heavy-duty trucks and buses would account for about 28 percent of 
nitrogen oxides emissions and 20 percent of particulate matter 
emissions from mobile sources. In some urban areas, the contribution is 
even greater. The 2007HD highway program will reduce particulate matter 
and oxides of nitrogen emissions from heavy-duty engines by 90 percent 
and 95 percent below current standard levels, respectively. In order to 
meet these more stringent standards for diesel engines, the program 
calls for a 97 percent reduction in the sulfur content of diesel fuel. 
As a result, diesel vehicles will achieve gasoline-like exhaust 
emission levels. We have also established more stringent standards for 
heavy-duty gasoline vehicles, based in part on the use of the low 
sulfur gasoline that will be available when the standards go into 
effect.
2. Emissions Control of Highway Engines and Vehicles Depends on 
Properly Operating Emissions Control Systems
    The emissions reductions and resulting health and welfare benefits 
of the 2007HD highway program will be dramatic when fully implemented. 
By 2030, the program will reduce annual emissions of nitrogen oxides, 
nonmethane hydrocarbons, and particulate matter by a projected 2.6 
million, 115,000 and 109,000 tons, respectively. However, to realize 
those large emission reductions and health benefits, the emission 
control systems on heavy-duty highway engines and vehicles must 
continue to provide the 90 to 95 percent emission control effectiveness 
throughout their operating life. Today's proposed OBD requirements will 
help to ensure that emission control systems continue to operate 
properly by detecting when those systems malfunction, by then notifying 
the driver that a problem exists that requires service and, lastly, by 
informing the service technician what the problem is so that it can be 
properly repaired.
3. Basis for Action Under the Clean Air Act
    Section 202(m) of the CAA, 42 U.S.C. 7521(m), directs EPA to 
promulgate regulations requiring 1994 and later model year light-duty 
vehicles (LDVs) and light-duty trucks (LDTs) to contain an OBD system 
that monitors emission-related components for malfunctions or 
deterioration ``which could cause or result in failure of the vehicles 
to comply with emission standards established'' for such vehicles. 
Section

[[Page 3205]]

202(m) also states that, ``The Administrator may, in the 
Administrator's discretion, promulgate regulations requiring 
manufacturers to install such onboard diagnostic systems on heavy-duty 
vehicles and engines.''
    Section 202(m)(5) of the CAA states that the Administrator shall 
require manufacturers to, ``provide promptly to any person engaged in 
the repairing or servicing of motor vehicles or motor vehicle engines * 
* * with any and all information needed to make use of the emission 
control diagnostics system prescribed under this subsection and such 
other information including instructions for making emission related 
diagnosis and repairs.''

D. How Has EPA Chosen the Level of the Proposed Emissions Thresholds?

    The OBD emissions thresholds that we are proposing are summarized 
in Tables II.B-1, II.C-1, II.H-1 and II.H-2. These tables show the 
actual threshold levels and how they relate to current emissions 
standards. Here, we wish to summarize how we chose those proposed 
thresholds. First, it is important to note that OBD is more than 
emissions thresholds. In fact, most OBD monitors are not actually tied 
to an emissions threshold. Instead, they monitor the performance of a 
given component or system and evaluate that performance based on 
electrical information (e.g., voltage within proper range) or 
temperature information (e.g., temperature within range), etc. Such 
monitors often detect malfunctions well before emissions are seriously 
compromised. Nonetheless, emissions thresholds are a critical element 
to OBD requirements since some components and systems, most notably any 
aftertreatment devices, cannot be monitored in simple electrical or 
temperature related terms. Instead, their operating characteristics can 
be measured and correlated to an emissions impact. This way, when those 
operating characteristics are detected, an unacceptable emissions 
increase can be inferred and a malfunction can be noted to the driver.
    Part of the challenge in establishing OBD requirements is 
determining the point--the OBD threshold--at which an unacceptable 
emissions increase has occurred that is detectable by the best 
available OBD technology. Two factors have gone into our determination 
of the emissions thresholds we are proposing: technological 
feasibility; and the costs and emissions reductions associated with 
repairs initiated as a result of malfunctions found by OBD systems. The 
first of these factors is discussed in more detail in section III where 
we present our case for the technological feasibility of the 
thresholds. In summary, we believe that the thresholds we are proposing 
are, while challenging, technologically feasible in the 2010 and later 
timeframe. We have carefully considered monitoring system capability, 
sensor capability, emissions measurement capability, test-to-test 
variability and, perhaps most importantly, the manufacturers' 
engineering and test cell resources and have arrived at thresholds we 
believe can be met on one engine family per manufacturer in the 2010 
model year and on all engine families by the 2013 model year.
    We believe that the proposed thresholds strike the proper balance 
between environmental protection, OBD and various sensor capabilities, 
and avoidance of repairs whose costs could be high compared to their 
emission control results. One must keep in mind that increasingly 
stringent OBD thresholds (i.e., OBD detection at lower emissions 
levels) may lead to more durable emission controls due to a 
manufacturer's desire to avoid the negative impression given their 
product upon an OBD detection. Such an outcome would result in lower 
fleetwide emissions while increasing costs to manufacturers. However, 
increasingly stringent OBD thresholds may also lead to more OBD 
detections and more OBD induced repairs and, perhaps, many OBD induced 
repairs for malfunctions having little impact on emissions. Such an 
outcome would result in lower fleetwide emissions while increasing 
costs to both manufacturers and truck owners.

E. World Wide Harmonized OBD (WWH-OBD)

    Within the United Nations (UN), the World Forum for Harmonization 
of Vehicle Regulations (WP.29) administers the 1958 Geneva Agreement 
(1958 Agreement) to facilitate the adoption of uniform conditions of 
approval and reciprocal recognition of approval for motor vehicle 
equipment and parts. As a result, WP.29 has responsibility for vehicle 
regulations within Europe and, indirectly, many countries outside of 
Europe that have voluntarily adopted the WP.29 regulations. The United 
States was never a party to the 1958 Agreement, but EPA has monitored 
the WP.29 regulations developed under the 1958 Agreement and we have 
benefited from a reciprocal consultative relationship with our European 
counterparts. More recently, WP.29 took on the responsibility of 
administering the 1998 Global Agreement that established a process to 
permit all regions of the world to jointly develop global technical 
regulations without required mutual recognition of approvals or 
designated compliance and enforcement. The United States is a signatory 
of the 1998 Global Agreement (1998 Agreement), and EPA has 
responsibility for representing the U.S. with respect to environmental 
issues within WP.29 as they pertain to the 1998 Agreement.
    During the one-hundred-and-twenty-sixth session of WP.29 of March 
2002, the Executive Committee (AC.3) of the 1998 Global Agreement (1998 
Agreement) adopted a Programme of Work, which includes the development 
of a Global Technical Regulation (GTR) concerning onboard diagnostic 
systems for heavy-duty vehicles and engines. An informal working 
group--the WWH-OBD working group--was established to develop the GTR. 
The working group was instructed that the OBD system should detect 
failures from the engine itself, as well as from the exhaust 
aftertreatment systems fitted downstream of the engine, and from the 
package of information exchanged between the engine electronic control 
unit(s) and the rest of vehicle and/or powertrain. The working group 
was also instructed to base the OBD requirements on the technologies 
expected to be industrially available at the time the GTR would be 
enforced, and to take into account both the expected state of 
electronics in the years 2005-2008 and the expected newest engine and 
aftertreatment technologies.
    In November 2003, AC.3 further directed the working group to 
structure the GTR in such a manner as to enable its future extension to 
other functions of the vehicle. In so doing, AC.3 did not revise the 
scope of the task given to the working group (i.e., the scope remained 
emissions-related heavy-duty OBD). As a result, the GTR is structured 
such that OBD monitoring and communications could be extended to other 
systems such as vehicle safety systems. This has been achieved by 
dividing the GTR into a set of generic OBD requirements to be followed 
by specific OBD requirements concerning any future desired OBD systems. 
The generic OBD requirements contain definitions and other OBD 
regulatory elements that are meant to be applicable throughout the GTR 
and all of its modules, annexes, and appendices. This generic section 
is followed by the first specific OBD section--emission-related OBD--
which contains definitions and OBD regulatory elements specific to 
emissions-related OBD.
    EPA has been active in the WWH-OBD working group for more than 
three

[[Page 3206]]

years. Because that group has been developing a regulation at the same 
time that we have been developing the requirements in this proposal, 
our proposed OBD requirements are consistent, for the most part, with 
the current efforts of the WWH-OBD group.
    The WWH-OBD working group submitted a draft GTR as a formal 
document in March of 2006. During the months immediately following, the 
WWH-OBD working group has made final revisions to the GTR and will 
submit it to WP.29 for consideration. If approved by WP.29 and adopted 
as a formal global technical regulation, we would intend to propose any 
revisions to our OBD regulations that might be necessary to make them 
consistent with WWH-OBD.\3\
---------------------------------------------------------------------------

    \3\ Note that, while the WWH-OBD GTR is consistent with many of 
the specific requirements we are proposing, it is not currently as 
comprehensive as our proposal (e.g., it does not contain the same 
level of detail with respect to certification requirements and 
enforcement provisions). For that reason, at this time, we do not 
believe that the GTR would fully replace what we are proposing 
today.
---------------------------------------------------------------------------

    The latest version of the draft WWH-OBD GTR has been placed in the 
docket for this rule.\4\ While it is not yet a final document, we are 
nonetheless interested in comments regarding the current version. More 
specifically, we are interested in comments regarding any possible 
inconsistencies between the requirements of the draft GTR and the 
requirements being proposed today. We believe that if such 
inconsistencies exist, they are minor. WWH-OBD provides a framework for 
nations to establish a heavy-duty OBD program. It has the potential to 
result in similar OBD systems, but the WWH-OBD GTR must fit into the 
context of any country's existing heavy-duty emissions regulations. For 
example, at this time, the draft GTR does not specify emissions 
threshold levels, implementation dates, or phase-in schedules. As such, 
our proposal today is much more detailed than the draft WWH-OBD GTR, 
but we believe there exist no major inconsistencies between the two 
regulations.
---------------------------------------------------------------------------

    \4\ ``Revised Proposal for New Draft Global Technical Regulation 
(gtr): Technical Requirements for On-Board Diagnostic Systems (OBD) 
for Road Vehicles;'' ECE/TRANS/WP.29/GRPE/2006/8/Rev.1; March 27, 
2006, Docket ID EPA-HQ-OAR-2005-0047-0004.
---------------------------------------------------------------------------

F. Onboard Diagnostics for Diesel Engines Used in Nonroad Land-Based 
Equipment

    We are also considering regulations--although we are not making any 
proposals today--that would require OBD systems on heavy-duty diesel 
engines used in nonroad land-based equipment. The pollution emitted by 
diesel nonroad engines contributes greatly to our nation's continuing 
air quality problems. Our recent Nonroad Tier 4 rulemaking was designed 
to address these serious air quality problems from land-based diesel 
engines. (69 FR 38958) Like with diesel highway emissions, these 
problems include premature mortality, aggravation of respiratory and 
cardiovascular disease, aggravation of existing asthma, acute 
respiratory symptoms, chronic bronchitis, and decreased lung function. 
And, as noted above, we believe that diesel exhaust is likely to be 
carcinogenic to humans by inhalation and that this cancer hazard exists 
for occupational and environmental levels of exposure.
    In our preamble to the Nonroad Tier 4 final rule, we estimated 
that, absent the nonroad Tier 4 standards, by 2020, land based nonroad 
diesel engines would account for as much as 70 percent of the diesel 
mobile source PM inventory. As part of our nonroad Tier 4 program, new 
emission standards will begin to take effect in calendar year 2011 that 
are based on the use of high-efficiency catalytic exhaust emission 
control devices or comparably effective advanced technologies. As with 
our 2007HD highway program, a cap is also included on the allowable 
sulfur content in nonroad diesel fuel.
    The diesel engines used in nonroad land-based equipment are, in 
certain horsepower ranges, often essentially the same as those used in 
heavy-duty highway trucks. In other horsepower ranges--e.g., very large 
nonroad machines with engines having more than 1,500 horsepower--the 
engine is quite different. Such differences can include the addition of 
cylinders and turbo chargers among other things. Notably, the new 
nonroad Tier 4 regulations will result in the introduction of advanced 
emissions control systems on nonroad land-based equipment; those 
advanced emissions control systems will be the same type of systems as 
those expected for highway diesel engines.
    Therefore, having OBD systems and OBD regulations for nonroad 
diesel engines seems to be a natural progression from the proposed 
requirements for heavy-duty highway engines. Nonetheless, we believe 
that there are differences between nonroad equipment and highway 
applications, and differences between the nonroad market and the 
highway market such that proposing the same OBD requirements for 
nonroad as for highway may not be appropriate. Therefore, we are 
providing advance notice to the public with the goal of soliciting 
public comment regarding how we should proceed with respect to nonroad 
OBD. This section presents issues we have identified and solicits 
comment. We also welcome comment with respect to other issues we have 
not addressed here, such as service information availability.
1. What Is the Baseline Nonroad OBD System?
    We know that highway diesel engines already use a sophisticated 
level of OBD system. For nonroad diesel engines in the 200 to 600 
horsepower range--i.e., the typical range of highway engines--are the 
current OBD system identical to their highway counterparts? How would 
the proposed highway OBD requirements change this, if at all? Do diesel 
engines outside the range typical of highway engines use OBD?
2. What Is the Appropriate Level of OBD Monitoring for Nonroad Diesel 
Engines?
    The proposed OBD requirements for highway engines are very 
comprehensive and would result in virtually every element of the 
emissions control system being monitored. Is this appropriate for 
nonroad diesel engines? And to what degree should such monitoring be 
required? The emissions thresholds proposed for highway engines will 
push OBD and sensor technology beyond where it is today because of 
their stringency. Is a similar level of stringency appropriate for 
nonroad engines? Should emissions thresholds analogous to those 
presented in Table II.B-1 of this preamble even be a part of any 
potential nonroad OBD requirements or should nonroad OBD rely more 
heavily on comprehensive component monitoring as discussed in section 
II.D.4 of this preamble? This latter question is particularly 
compelling given the incredibly broad range of operating 
characteristics for nonroad equipment. Similar to the issue of 
emissions thresholds, certain aspects of the proposed highway OBD 
requirements carry with them serious concerns given the range of use 
for heavy-duty highway trucks (line-haul trucks versus garbage trucks 
versus urban delivery trucks, etc.). As discussed in various places in 
section II of this preamble, this broad range of uses makes it 
difficult for manufacturers to design a single approach that would, for 
example, ensure frequent monitoring events on all possible 
applications. This difficulty could be even more pronounced in the 
nonroad industry given the greater number of possible applications.

[[Page 3207]]

    We request comment regarding what any potential nonroad OBD 
monitoring requirements should look like. More specifically, we request 
comment regarding the inclusion of emissions thresholds versus relying 
solely on comprehensive component monitoring. From commenters in favor 
of emissions thresholds, we request details regarding the appropriate 
level of emissions thresholds including data and strong engineering 
analyses for/against the suggested level. We request comment regarding 
the comprehensiveness of monitoring (i.e., the entire emissions control 
system, aftertreatement devices only, feedback control systems only, 
etc.).
3. What Should the OBD Standardization Features Be?
    Should nonroad OBD include a requirement for a dedicated, OBD-only 
malfunction indicator light? Should nonroad OBD require specific 
communication protocols for communication of onboard information to 
offboard devices and scan tools? What should those protocols be? What 
are the needs of the nonroad service industry with respect to 
standardization of onboard to offboard communications?
4. What Are the Prospects and/or Desires for International 
Harmonization of Nonroad OBD?
    Nonroad equipment is perhaps the most international of all mobile 
source equipment. Land based nonroad equipment, while not as much so as 
marine equipment, tends to be designed, produced, marketed, and sold to 
a world market to a greater extent than is highway equipment. Given 
that, is there a sense within the nonroad industry that international 
harmonization is important? Imperative? Is the proper avenue for 
putting into place nonroad OBD regulations the WWH-OBD process 
discussed above? If so, is industry prepared to play a role in 
developing a nonroad OBD element to the WWH-OBD document? Are other 
government representatives prepared to do so?

II. What Are the Proposed OBD Requirements and When Would They Be 
Implemented?

    The following subsections describe our proposed OBD monitoring 
requirements and the timelines for their implementation. The 
requirements are indicative of our goal for the program which is a set 
of OBD monitors that provide robust diagnosis of the emission control 
system. Our intention is to provide industry sufficient time and 
experience with satisfying the demands of the proposed OBD program. 
While their engines already incorporate OBD systems, those systems are 
generally less comprehensive and do not monitor the emission control 
system in the ways we are proposing. Additionally, the proposed OBD 
requirements represent a new set of technological requirements and a 
new set of certification requirements for the industry in addition to 
the 2007HD highway program and its challenging emission standards for 
PM and NOX and other pollutants. As a result, we believe the 
monitoring requirements and timelines outlined in this section 
appropriately weigh the need for OBD monitors on the emission control 
system and the need to gain experience with not only those monitors but 
also the newly or recently added emission control hardware.
    We request comment on all aspects of the requirements laid out in 
this section and throughout this preamble. As discussed in Section IX, 
we are also interested in comments concerning state run HDOBD-based 
inspection and maintenance (I/M) programs, the level of interest in 
such programs, and comments concerning the suitability of today's 
proposed OBD requirements toward facilitating potential HDOBD I/M 
programs in the future.

A. General OBD System Requirements

1. The OBD System
    We are proposing that the OBD system be designed to operate for the 
actual life of the engine in which it is installed. Further, the OBD 
system cannot be programmed or otherwise designed to deactivate based 
on age and/or mileage of the vehicle during the actual life of the 
engine. This requirement is not intended to alter existing law and 
enforcement practice regarding a manufacturer's liability for an engine 
beyond its regulatory useful life, except where an engine has been 
programmed or otherwise designed so that an OBD system deactivates 
based on age and/or mileage of the engine.
    We are also proposing that computer coded engine operating 
parameters not be changeable without the use of specialized tools and 
procedures (e.g. soldered or potted computer components or sealed (or 
soldered) computer enclosures). Upon Administrator approval, certain 
product lines may be exempted from this requirement if those product 
lines can be shown to not need such protections. In making the approval 
decision, the Administrator will consider such things as the current 
availability of performance chips, performance capability of the 
engine, and sales volume.
2. Malfunction Indicator Light (MIL) and Diagnostic Trouble Codes (DTC)
    Upon detecting a malfunction within the emission control system,\5\ 
the OBD system must make some indication to the driver so that the 
driver can take action to get the problem repaired. The proposal would 
require that a dashboard malfunction indicator light (MIL) be 
illuminated to inform the driver that a problem exists that needs 
attention. Upon illumination of the MIL, the proposal would require 
that a diagnostic trouble code (DTC) be stored in the engine's computer 
that identifies the detected malfunction. This DTC would then be read 
by a service technician to assist in making the necessary repair.
---------------------------------------------------------------------------

    \5\ What constitutes a ``malfunction'' for over 14,000 pound 
applications under today's proposal is covered in section II.B for 
diesel engines, section II.C for gasoline engines, and section II.D 
for all engines.
---------------------------------------------------------------------------

    Because the MIL is meant to inform the driver of a detected 
malfunction, we are proposing that the MIL be located on the driver's 
side instrument panel and be of sufficient illumination and location to 
be readily visible under all lighting conditions. We are proposing that 
the MIL be amber (yellow) in color when illuminated because yellow is 
synonymous with the notion of a ``cautionary warning''; the use of red 
for the MIL would be strictly prohibited because red signifies 
``danger'' which is not the proper message for malfunctions detected 
according to today's proposal. Further, we are proposing that, when 
illuminated, the MIL display the International Standards Organization 
(ISO) engine symbol because this symbol has become accepted after 10 
years of light-duty OBD as a communicator of engine and emissions 
system related problems. We are also proposing that there be only one 
MIL used to indicate all malfunctions detected by the OBD system on a 
single vehicle. We believe this is important to avoid confusion over 
multiple lights and, potentially, multiple interpretations of those 
lights. Nonetheless, we seek comment on this limitation to one 
dedicated MIL to communicate emissions-related malfunctions. We also 
seek comment on the requirement that the MIL be amber in color since 
some trucks may use liquid crystal display (LCD) panels to display 
dashboard information and some such panels are monochromic and unable 
to display color.
    We are also interested in comments regarding the malfunction 
indicator light and the symbol displayed to

[[Page 3208]]

communicate that there is an engine and/or emission-related 
malfunction. As noted, we are proposing use of the ISO engine symbol as 
shown in Table II.A-1. The U.S. Department of Transportation has 
proposed use of an alternative ISO symbol to denote, specifically, an 
emission-related malfunction. (68 FR 55217) That symbol is also shown 
in Table II.A-1. While we are not proposing that this alternative 
symbol be used, comments are solicited regarding whether this 
alternative symbol provides a clearer message to the driver.
    Generally, a manufacturer would be allowed sufficient time to be 
certain that a malfunction truly exists before illuminating the MIL. No 
one benefits if the MIL illuminates spuriously when a real malfunction 
does not exist. Thus, for most OBD monitoring strategies, manufacturers 
would not be required to illuminate the MIL until a malfunction clearly 
exists which will be considered to be the case when the same problem 
has occurred on two sequential driving cycles.\6\
---------------------------------------------------------------------------

    \6\ Generally, a ``driving cycle'' or ``drive cycle'' consists 
of engine startup and engine shutoff or consists of four hours of 
continuous engine operation.
[GRAPHIC] [TIFF OMITTED] TP24JA07.000

    To keep this clear in the onboard computer, we are proposing that 
the OBD system make certain distinctions between the problems it has 
detected, and that the system maintain a strict logic for diagnostic 
trouble code (DTC) storage/erasure and for MIL illumination/
extinguishment. Whenever the enable criteria for a given monitor are 
met, we would expect that monitor to run. For continuous monitors, this 
would be during essentially all engine operation.\7\ For non-continuous 
monitors, it would be during only a subset of engine operation.\8\ In 
general, we are proposing that monitors make a diagnostic decision just 
once per drive cycle that contains operation satisfying the enable 
criteria for the given monitor.
---------------------------------------------------------------------------

    \7\ A ``continuous'' monitor--if used in the context of 
monitoring conditions for circuit continuity, lack of circuit 
continuity, circuit faults, and out-of-range values--means sampling 
at a rate no less than two samples per second. If a computer input 
component is sampled less frequently for engine control purposes, 
the signal of the component may instead be evaluated each time 
sampling occurs.
    \8\ A ``non-continuous'' monitor being a monitor that runs only 
when a limited set of operating conditions occurs.
---------------------------------------------------------------------------

    When a problem is first detected, we are proposing that a 
``pending'' DTC be stored. If, during the subsequent drive cycle that 
contains operation satisfying the enable criteria for the given 
monitor, a problem in the components/system is not again detected, the 
OBD system would declare that a malfunction does not exist and would, 
therefore, erase the pending DTC. However, if, during the subsequent 
drive cycle that contains operation satisfying the enable criteria for 
the given monitor, a problem in the component/system is again detected, 
a malfunction has been confirmed and, hence, a ``confirmed'' or ``MIL-
on'' DTC would be stored.\9\ Section II.F presents the requirements for 
standardization of OBD information and communications. Upon storage of 
a MIL-on DTC and, depending on the communication protocol used--ISO 
15765-4 or SAE J1939--the pending DTC would either remain stored or be 
erased, respectively. Today's proposal neither stipulates which 
communication protocol nor which pending DTC logic be used. We are 
proposing to allow the use of either of the existing protocols as is 
discussed in more detail in section II.F. Upon storage of the MIL-on 
DTC, the MIL must be illuminated.\10\ Also at this time, a 
``permanent'' DTC would be stored (see section II.F.4 for more details 
regarding permanent DTCs and our rationale for proposing them).\11\
---------------------------------------------------------------------------

    \9\ Different industry standards organizations--the Society of 
Automotive Engineers (SAE) and the International Standards 
Organization (ISO)--use different terminology to refer to a ``MIL-
on'' DTC. For clarity, we use the term ``MIL-on'' DTC throughout 
this preamble to convey the concept and not any requirement that 
standard making bodies use the term in their standards.
    \10\ Throughout this proposal, we refer to MIL illumination to 
mean a steady, continuous illumination during engine operation 
unless stated otherwise. This contrasts with the MIL illumination 
logic used by many engine manufacturers today by which the MIL would 
illuminate upon detection of a malfunction but would remain 
illuminated only while the malfunction was actually occurring. Under 
this latter logic, an intermittent malfunction or one that occurs 
under only limited operating conditions may result in a MIL that 
illuminates, extinguishes, illuminates, etc., as operating 
conditions change.
    \11\ A permanent DTC must be stored in a manner such that 
electrical disconnections do not result in their erasure (i.e., they 
must be stored in non-volatile random access memory (NVRAM)).
---------------------------------------------------------------------------

    We are also proposing that, after three subsequent drive cycles 
that contain operation satisfying the enable criteria for the given 
monitor without any recurrence of the previously detected malfunction, 
the MIL should be extinguished (unless there are other MIL-on DTCs 
stored for which the MIL must also be illuminated), the permanent DTC 
should be erased, but a ``previous-MIL-on'' DTC should remain 
stored.\12\ We are proposing that the previous MIL-on DTC remain stored 
for 40 engine warmup cycles after which time, provided the identified 
malfunction has not been detected again and the MIL is presently not 
illuminated for that malfunction, the previous-MIL-on DTC can be 
erased.\13\ However, if an illuminated MIL is not extinguished, or if a 
MIL-on DTC is not erased, by the OBD system itself but is instead 
erased via scan tool or battery disconnect (which would erase all non-
permanent, volatile memory), the permanent DTC must remain stored. This 
way, permanent DTCs can only be erased by the OBD system itself and 
cannot be erased through human interaction with the system.
---------------------------------------------------------------------------

    \12\ This general ``three trip'' condition for extinguishing the 
MIL is true for all but two diesel systems/monitors--the misfire 
monitor and the SCR system--and three gasoline systems/monitors--the 
fuel system, the misfire monitor, and the evaporative system--which 
have further conditions on extinguishing the MIL This is discussed 
in more detail in sections II.B and II.C.
    \13\ For simplicity, the discussion here refers to ``previous-
MIL-on'' DTCs only. The ISO 15765 standard and the SAE J1939 
standard use different terms to refer to the concept of a previous-
MIL-on DTC. Our intent is to present the concept of our proposal in 
this preamble and not to specify the terminology used by these 
standard making bodies.
---------------------------------------------------------------------------

    We are proposing that the manufacturer be allowed, upon

[[Page 3209]]

Administrator approval, to use alternative statistical MIL illumination 
and DTC storage protocols to those described above (i.e., alternatives 
to the ``first trip--pending DTC, second strip--MIL-on DTC logic). The 
Administrator would consider whether the manufacturer provided data 
and/or engineering evaluation adequately demonstrates that the 
alternative protocols can evaluate system performance and detect 
malfunctions in a manner that is equally effective and timely. 
Alternative strategies requiring, on average, more than six driving 
cycles for MIL illumination would probably not be accepted.
    Upon storage of either a pending DTC and/or a MIL-on DTC, we are 
proposing that the computer store a set of ``freeze frame'' data. This 
freeze frame data would provide a snap shot of engine operating 
conditions present at the time the malfunction occurred and was 
detected. This information serves the repair technician in diagnosing 
the problem and conducting the proper repair. The freeze frame data 
should be stored upon storage of a pending DTC. If the pending DTC 
matures to a MIL-on DTC, the manufacturer can choose to update the 
freeze frame data or retain the freeze frame stored in conjunction with 
the pending DTC. Likewise, any freeze frame stored in conjunction with 
any pending or MIL-on DTC should be erased upon erasure of the DTC. 
Further information concerning the freeze frame requirement and the 
data required in the freeze frame is presented in section II.F.4, 
below.
    We are also proposing that the OBD system illuminate the MIL and 
store a MIL-on DTC to inform the vehicle operator whenever the engine 
enters a mode of operation that can affect the performance of the OBD 
system. If such a mode of operation is recoverable (i.e., operation 
automatically returns to normal at the beginning of the following 
ignition cycle \14\), then in lieu of illuminating the MIL when the 
mode of operation is entered, the OBD system may wait to illuminate the 
MIL and store the MIL-on DTC if the mode of operation is again entered 
before the end of the next ignition cycle. We are proposing this 
because many operating strategies are designed such that they continue 
automatically through to the next key-off. Regardless, upon the next 
key-on, the engine control would start off in ``normal'' operating mode 
and would return to the ``abnormal'' operating mode only if the 
condition causing the abnormal mode was again encountered. In such 
cases, we are proposing to allow that the MIL be illuminated during the 
second consecutive drive cycle during which such an ``abnormal'' mode 
is engaged.\15\
---------------------------------------------------------------------------

    \14\ ``Ignition Cycle'' means a drive cycle that begins with 
engine start and includes an engine speed that exceeds 50 to 150 
rotations per minute (rpm) below the normal, warmed-up idle speed 
(as determined in the drive position for vehicles equipped with an 
automatic transmission) for at least two seconds plus or minus one 
second.
    \15\ Note that we use the term ``abnormal'' to refer to an 
operating mode that the engine is designed to enter upon determining 
that ``normal'' operation cannot be maintained. Therefore, the term 
``abnormal'' is somewhat of a misnomer since the engine is doing 
what it has been designed to do. Nonetheless, the abnormal operating 
mode is clearly not the operating mode the manufacturer has intended 
for optimal operation. Such operating modes are sometimes referred 
to as ``default'' operating modes or ``limp-home'' operating modes.
---------------------------------------------------------------------------

    Whether or not the ``abnormal'' mode of operation is recoverable, 
in this context, has nothing to do with whether the detected 
malfunction goes away or stays. Instead, it depends solely on whether 
or not the engine, by design, will stay in abnormal operating mode on 
the next key-on. We are proposing this MIL logic because often the 
diagnostic (i.e., monitor) that caused the engine to enter abnormal 
mode cannot run again once the engine is in the abnormal mode. So, if 
the MIL logic associated with abnormal mode activation was always a 
two-trip diagnostic, abnormal mode activation would set a pending DTC 
on the first trip and, since the system would then be stuck in that 
abnormal operating mode and would never be able to run the diagnostic 
again, the pending DTC could never mature to a MIL-on DTC nor 
illuminate the MIL. Hence, the MIL must illuminate upon the first entry 
into such an abnormal operating mode. If such a mode is recoverable, 
the engine will start at the next key-on in ``normal'' mode allowing 
the monitor to run again and, assuming another detection of the 
condition, the system would set a MIL-on DTC and illuminate the MIL.
    The OBD system would not need to store a DTC nor illuminate the MIL 
upon abnormal mode operation if other telltale conditions would result 
in immediate action by the driver. Such telltale conditions would be, 
for example, an overt indication like a red engine shut-down warning 
light. The OBD system also need not store a DTC nor illuminate the MIL 
upon abnormal mode operation if the mode is indeed an auxiliary 
emission control device (AECD) approved by the Administrator.
    There may be malfunctions of the MIL itself that would prevent it 
from illuminating. A repair technician--or possibly an I/M inspector--
would still be able to determine the status of the MIL (i.e., commanded 
``on'' or ``off'') by reading electronic information available through 
a scan tool, but there would be no indication to the driver of an 
emissions-related malfunction should one occur. Unidentified 
malfunctions may cause excess emissions to be emitted from the vehicle 
and may even cause subsequent deterioration or failure of other 
components or systems without the driver's knowledge. In order to 
prevent this, the manufacturer must ensure that the MIL is functioning 
properly. For this reason, we are proposing two requirements to check 
the functionality of the MIL itself. First, the MIL would be required 
to illuminate for a minimum of five seconds when the vehicle is in the 
key-on, engine-off position. This allows an interested party to check 
the MIL's functionality simply by turning the key to the key-on 
position. While the MIL would be physically illuminated during this 
functional check, the data stream value for the MIL command status 
would be required to indicate ``off'' during this check unless, of 
course, the MIL was currently being commanded ``on'' for a detected 
malfunction. This functional check of the MIL would not be required 
during vehicle operation in the key-on, engine-off position subsequent 
to the initial engine cranking of an ignition cycle (e.g., due to an 
engine stall or other non-commanded engine shutoff).
    The second functional check requirement we are proposing requires 
the OBD system to perform a circuit continuity check of the electrical 
circuit that is used to illuminate the MIL to verify that the circuit 
is not shorted or open (e.g., a burned out bulb). While there would not 
be an ability to illuminate the MIL when such a malfunction is 
detected, the electronically readable MIL command status in the onboard 
computer would be changed from commanded ``off'' to ``on''. This would 
allow the truck owner or fleet maintenance staff to quickly determine 
whether an extinguished MIL means ``no malfunctions'' or ``broken 
MIL.'' It would also serve, should it become of interest in the future, 
complete automation of the I/M process by eliminating the need for 
inspectors to input manually the results of their visual inspections. 
Feedback from passenger car I/M programs indicates that the current 
visual bulb check performed by inspectors is subject to error and 
results in numerous vehicles being falsely failed or passed. By 
requiring monitoring of the circuit itself, the entire pass/fail 
criteria of an I/M program could be determined by the electronic 
information available through a scan tool, thus better facilitating 
quick

[[Page 3210]]

and effective inspections and minimizing the chance for manually-
entered errors.
    At the manufacturer's option, the MIL may be used to indicate 
readiness status in a standardized format (see Section II.F) in the 
key-on, engine-off position. Readiness status is a term used in light-
duty OBD that refers to a vehicle's readiness for I/M inspection. For a 
subset of monitors--those that are non-continuous monitors for which an 
emissions threshold exists (see sections II.B and II.C for more on 
emissions thresholds)--a readiness status indicator must be stored in 
memory to indicate whether or not that particular monitor has run 
enough times to make a diagnostic decision. Until the monitor has run 
sufficient times, the readiness status would indicate ``not ready''. 
Upon running sufficient times, the readiness status would indicate 
``ready.'' This serves to protect against drivers disconnecting their 
battery just prior to the I/M inspection so as to erase any MIL-on 
DTCs. Such an action would simultaneously set all readiness status 
indicators to ``not ready'' resulting in a notice to return to the 
inspection site at a future date. Readiness indicators also help repair 
technicians because, after completing a repair, they can operate the 
vehicle until the readiness status indicates ``ready'' and, provided no 
DTCs are stored, know that the repair has been successful. We are 
proposing that HDOBD systems follow this same readiness status logic as 
used for years in light-duty OBD both to assist repair technicians and 
to facilitate potential future HDOBD I/M programs.
    We are also proposing that the manufacturer, upon Administrator 
approval, be allowed to use the MIL to indicate which, if any, DTCs are 
currently stored (e.g., to ``blink'' the stored codes). The 
Administrator would approve the request if the manufacturer can 
demonstrate that the method used to indicate the DTCs will not be 
unintentionally activated during any inspection test or during routine 
driver operation.
3. Monitoring Conditions
a. Background
    Given that the intent of the proposed OBD requirements is to 
monitor the emission control system for proper operation, it is logical 
that the OBD monitors be designed such that they monitor the emission 
control system during typical driving conditions. While many OBD 
monitors would be designed such that they are continuously making 
decisions about the operational status of the engine, many--and 
arguably the most critical--monitors are not so designed. For example, 
an OBD monitor whose function is to monitor the active fuel injection 
system of a NOX adsorber or a DPF cannot be continuously 
monitoring that function since that function occurs on an infrequent 
basis. This OBD monitor presumably would be expected to ``run,'' or 
evaluate the active injection system, during an actual fuel injection 
event.
    For this reason, manufacturers are allowed to determine the most 
appropriate times to run their non-continuous OBD monitors. This way, 
they are able to make an OBD evaluation either at the operating 
condition when an emission control system is active and its operational 
status can best be evaluated, and/or at the operating condition when 
the most accurate evaluation can be made (e.g., highly transient 
conditions or extreme conditions can make evaluation difficult). 
Importantly, manufacturers are prohibited from using a monitoring 
strategy that is so restrictive such that it rarely or never runs. To 
help protect against monitors that rarely run, we are proposing an 
``in-use monitor performance ratio'' requirement which is detailed in 
section II.E.
    The set of operating conditions that must be met so that an OBD 
monitor can run are called the ``enable criteria'' for that given 
monitor. These enable criteria are often different for different 
monitors and may well be different for different types of engines. A 
large diesel engine intended for use in a Class 8 truck would be 
expected to see long periods of relatively steady-state operation while 
a smaller engine intended for use in an urban delivery truck would be 
expected to see a lot of transient operation. Manufacturers will need 
to balance between a rather loose set of enable criteria for their 
engines and vehicles given the very broad range of operation HD highway 
engines see and a tight set of enable criteria given the desire for 
greater monitor accuracy.
b. General Monitoring Conditions
i. Monitoring Conditions for All Engines
    As guidance to manufacturers, we are proposing the following 
criteria to assist manufacturers in developing their OBD enable 
criteria. These criteria would be used by the Agency during our OBD 
certification approval process to ensure that monitors run on a 
frequent basis during real world driving conditions. These criteria 
would be:
     The monitors should run during conditions that are 
technically necessary to ensure robust detection of malfunctions (e.g., 
to avoid false passes and false indications of malfunctions);
     The monitor enable criteria should ensure monitoring will 
occur during normal vehicle operation; and,
     Monitoring should occur during at least one test used by 
EPA for emissions verification `` either the HD Federal Test Procedure 
(FTP) transient cycle, or the Supplementary Emissions Test (SET).\16\
---------------------------------------------------------------------------

    \16\ See 40 CFR part 86, subpart N for details of EPA's test 
procedures.
---------------------------------------------------------------------------

    As discussed in more detail in sections II.B through II.D, we are 
proposing that manufacturers define the monitoring conditions, subject 
to Administrator approval, for detecting the malfunctions required by 
this proposal. The Administrator would determine if the monitoring 
conditions proposed by the manufacturer for each monitor abide by the 
above criteria.
    In general, except as noted in sections II.B through II.D, the 
proposed regulation would require each monitor to run at least once per 
driving cycle in which the applicable monitoring conditions are met. 
The proposal would also require certain monitors to run continuously 
throughout the driving cycle. These include a few threshold monitors 
(e.g., fuel system monitor) and most circuit continuity monitors. While 
a basic definition of a driving cycle (e.g., from ignition key-on and 
engine startup to engine shutoff) has been sufficient for passenger 
cars, the driving habits of many types of vehicles in the heavy-duty 
industry dictate an alternate definition. Specifically, many heavy-duty 
operators will start the engine and leave it running for an entire day 
or, in some cases, even longer. As such, we are proposing that any 
period of continuous engine-on operation of four hours be considered a 
complete driving cycle. A new driving cycle would begin following such 
a four hour period, regardless of whether or not the engine had been 
shut down. Thus, the ``clock'' for monitors that are required to run 
once per driving cycle would be reset to run again (in the same key-on 
engine start or trip) once the engine has been operated beyond four 
hours continuously. This would avoid an unnecessary delay in detection 
of malfunctions simply because the heavy-duty vehicle operator has 
elected to leave the vehicle running continuously for an entire day or 
days at a time.
    Manufacturers may request Administrator approval to define 
monitoring conditions that are not encountered during the FTP cycle. In 
evaluating the manufacturer's request, the Administrator will consider 
the degree to which the requirement to run

[[Page 3211]]

during the FTP cycle restricts in-use monitoring, the technical 
necessity for defining monitoring conditions that are not encountered 
during the FTP cycle, data and/or an engineering evaluation submitted 
by the manufacturer which demonstrate that the component/system does 
not normally function, or monitoring is otherwise not feasible, during 
the FTP cycle, and, where applicable, the ability of the manufacturer 
to demonstrate that the monitoring conditions will satisfy the minimum 
acceptable in-use monitor performance ratio requirement as defined 
below.
ii. In-Use Performance Tracking Monitoring Conditions
    In addition to the general monitoring conditions above, we are 
proposing that manufacturers be required to implement software 
algorithms in the OBD system to individually track and report in-use 
performance of the following monitors in the standardized format 
specified in section II.E:
 Diesel NMHC converting catalyst(s)
 Diesel NOX converting catalyst(s)
 Gasoline catalyst(s)
 Exhaust gas sensor(s)
 Gasoline evaporative system
 Exhaust gas recirculation (EGR) system
 Variable valve timing (VVT) system
 Gasoline secondary air system
 Diesel particulate filter system
 Diesel boost pressure control system
 Diesel NOX adsorber(s)
    The OBD system is not required to track and report in-use 
performance for monitors other than those specifically identified 
above.
iii. In-Use Performance Ratio Requirement
    We are also proposing that, for all 2013 and subsequent model year 
engines, manufacturers be required to define monitoring conditions 
that, in addition to meeting the general monitoring conditions, ensure 
that certain monitors yield an in-use performance ratio (which monitors 
and the details that define the performance ratio are defined in 
section II.E) that meets or exceeds the minimum acceptable in-use 
monitor performance ratio for in-use vehicles. We are proposing a 
minimum acceptable in-use monitor performance ratio of 0.100 for all 
monitors specifically required to track in-use performance. This means 
that the monitors listed in section II.A.3.ii above must run and make 
valid diagnostic decisions during 10 percent of the vehicle's trips. We 
intend to work with industry during the initial years of implementation 
to gather data on in-use performance ratios and may revise this ratio 
lower as appropriate depending on what we learn.
    Note that manufacturers may not use the calculated ratio (or any 
element thereof), or any other indication of monitor frequency, as a 
monitoring condition for a monitor. For example, the manufacturer would 
not be allowed to use a low ratio to enable more frequent monitoring 
through diagnostic executive priority or modification of other 
monitoring conditions, or to use a high ratio to enable less frequent 
monitoring.
4. Determining the Proper OBD Malfunction Criteria
    For determining the malfunction criteria for diesel engine monitors 
associated with an emissions threshold (see sections II.B and II.C for 
more on emissions thresholds), we are proposing that manufacturers be 
required to determine the appropriate emissions test cycle such that 
the most stringent monitor would result. In general, we believe that 
manufacturers can make this determination based on engineering 
judgement, but there may be situations where testing would be required 
to make the determination. We do not necessarily anticipate challenging 
a manufacturer's determination of which test cycle to use. Nonetheless, 
the manufacturer should be prepared, perhaps with test data, to justify 
their determination.
    We are also proposing that, for engines equipped with emission 
controls that experience infrequent regeneration events (e.g., a DPF 
and/or a NOX adsorber), a manufacturer must adjust the 
emission test results for monitors that are required to indicate a 
malfunction before emissions exceed a certain emission threshold.\17\ 
For each such monitor, the manufacturer would have to adjust the 
emission result as done in accordance with the provisions of section 
86.004-28(i) with the component for which the malfunction criteria are 
being established having been deteriorated to the malfunction 
threshold. As proposed, the adjusted emission value must be used for 
purposes of determining whether or not the applicable emission 
threshold is exceeded.
---------------------------------------------------------------------------

    \17\ See proposed Sec.  86.010-18(f).
---------------------------------------------------------------------------

    While we believe that this adjustment process for monitors of 
systems that experience infrequent regeneration events makes sense and 
would result in robust monitors, we also believe that it could prove to 
be overly burdensome for manufacturers. For example, a NOX 
adsorber threshold being evaluated by running an FTP using a 
``threshold'' part (i.e., a NOX adsorber deteriorated such 
that tailpipe emissions are at the applicable thresholds) may be 
considered acceptable provided the NOX adsorber does not 
regenerate during the test, but it may be considered unacceptable if 
the NOX adsorber does happen to regenerate during the test. 
This could happen because emissions would be expected to increase 
slightly during the regeneration event thereby causing emissions to be 
slightly above the applicable threshold. This would require the 
manufacturer to recalibrate the NOX adsorber monitor to 
detect at a lower level of deterioration to ensure that a regeneration 
event would not cause an exceedance of the threshold during an 
emissions test. After such a recalibration, the emissions occurring 
during the regeneration event would be lower than before because the 
new ``threshold'' NOX adsorber would have a slightly higher 
conversion efficiency. We are concerned that manufacturers may find 
themselves in a difficult iterative process calibrating such monitors 
that, in the end, will not be correspondingly more effective.
    For this reason, we request comment regarding the burden associated 
with the need to consider regeneration events in determining compliance 
with emissions thresholds. We also request comment on how to address 
any environmental concern versus the burden. Would it perhaps be best 
to simply use the emissions adjustments that are determined in 
accordance with section 86.004-28(i)? Is it necessary to even consider 
regeneration emissions when determining emission threshold compliance 
or is it perhaps best to ignore regeneration events in determining 
threshold calibrations?

B. Monitoring Requirements and Timelines for Diesel-Fueled/Compression-
Ignition Engines

    Table II.B-1 summarizes the proposed diesel fueled compression 
ignition emissions thresholds at which point a component or system has 
failed to the point of requiring an illuminated MIL and a stored DTC. 
More detail regarding the specific monitoring requirements, 
implementation schedules, and liabilities can be found in the sections 
that follow.

[[Page 3212]]



          Table II.B-1.--Proposed Emissions Thresholds for Diesel Fueled CI Engines over 14,000 Pounds
----------------------------------------------------------------------------------------------------------------
                     Component/monitor                           MY         NMHC      CO      NOX         PM
----------------------------------------------------------------------------------------------------------------
NMHC catalyst system......................................     2010-2012     2.5x  .......  .......  ...........
                                                                   2013+       2x  .......  .......  ...........
NOX catalyst system.......................................         2010+  .......  .......     +0.3  ...........
DPF system................................................     2010-2012     2.5x  .......  .......   0.05/+0.04
                                                                   2013+       2x  .......  .......   0.05/+0.04
Air-fuel ratio sensors upstream...........................     2010-2012     2.5x     2.5x     +0.3   0.03/+0.02
                                                                   2013+       2x       2x     +0.3   0.03/+0.02
Air-fuel ratio sensors downstream.........................     2010-2012     2.5x  .......     +0.3   0.05/+0.04
                                                                   2013+       2x  .......     +0.3   0.05/+0.04
NOX sensors...............................................         2010+  .......  .......     +0.3   0.05/+0.04
``Other monitors'' with emissions thresholds (see section      2010-2012     2.5x     2.5x     +0.3   0.03/+0.02
 II.B)....................................................
                                                                   2013+       2x       2x     +0.3   0.03/+0.02
----------------------------------------------------------------------------------------------------------------
Notes: MY=Model Year; 2.5x means a multiple of 2.5 times the applicable emissions standard or family emissions
  limit (FEL); +0.3 means the standard or FEL plus 0.3; 0.05/+0.04 means an absolute level of 0.05 or an
  additive level of the standard or FEL plus 0.04, whichever level is higher; not all proposed monitors have
  emissions thresholds but instead rely on functionality and rationality checks as described in section II.D.4.

    There are exceptions to the emissions thresholds shown in Table 
II.B-1 whereby a manufacturer can demonstrate that emissions do not 
exceed the threshold even when the component or system is non-
functional at which point a functional check would be allowed.
    Note that, in general, the monitoring strategies designed to meet 
the requirements discussed below should not involve the alteration of 
the engine control system or the emissions control system such that 
tailpipe emissions would increase. We do not want emissions to 
increase, even for short durations, for the sole purpose of monitoring 
the systems intended to control emissions. The Administrator would 
consider such monitoring strategies on a case-by-case basis taking into 
consideration the emissions impact and duration of the monitoring 
event. However, much effort has been expended in recent years to 
minimize engine operation that results in increased emissions and we 
encourage manufacturers to develop monitoring strategies that do not 
require alteration of the basic control system.
1. Fuel System Monitoring
a. Background
    The fuel system of a diesel engine is an essential component of the 
engine's emissions control system. Proper delivery of fuel--quantity, 
pressure, and timing--can play a crucial role in maintaining low 
engine-out emissions. The performance of the fuel system is also 
critical for aftertreatment device control strategies. As such, 
thorough monitoring of the fuel system is an essential element in an 
OBD system. The fuel system is primarily comprised of a fuel pump, fuel 
pressure control device, and fuel injectors. Additionally, the fuel 
system generally has sophisticated control strategies that utilize one 
or more feedback sensors to ensure the proper amount of fuel is being 
delivered to the cylinders. While gasoline engines have undergone 
relatively minor hardware changes (but substantial fine-tuning in the 
control strategy and feedback inputs), diesel engines have more 
recently undergone substantial changes to the fuel system hardware and 
now incorporate more refined control strategies and feedback inputs.
    For diesel engines, a substantial change has occurred in recent 
years as manufacturers have transitioned to new high-pressure fuel 
systems. One of the most widely used is a high-pressure common-rail 
fuel injection system, which is generally comprised of a high-pressure 
fuel pump, a fuel rail pressure sensor, a common fuel rail that feeds 
all injectors, individual fuel injectors that directly control fuel 
injection quantity and timing for each cylinder, and a closed-loop 
feedback system that uses the fuel rail pressure sensor to achieve the 
commanded fuel rail pressure. Unlike older style fuel systems where 
fuel pressure was mechanically linked to engine speed (and thus, varied 
from low to high as engine speed increased), common-rail systems are 
capable of controlling fuel pressure independent of engine speed. This 
increase in fuel pressure control allows greater flexibility in 
optimizing the performance and emission characteristics of the engine. 
The ability of the system to generate high pressure independent of 
engine speed also improves fuel delivery at low engine speeds.
    Precise control of the fuel injection timing is crucial for optimal 
engine and emission performance. As injection timing is advanced (i.e., 
fuel injection occurs earlier), hydrocarbon (HC) emissions and fuel 
consumption are decreased but oxides of nitrogen (NOX) 
emissions are increased. As injection timing is retarded (i.e., fuel 
injection occurs later), NOX emissions can be reduced but HC 
emissions, particulate matter (PM) emissions, and fuel consumption 
increase. Most modern diesel fuel systems even provide engine 
manufacturers with the ability to separate a single fuel injection 
event into discrete events such as pilot (or pre) injection, main 
injection, and post injection.
    Given the important role that modern diesel fuel systems play in 
emissions control, malfunctions or deterioration that would affect the 
fuel pressure control, injection timing, pilot/main/post injection 
timing or quantity, or ability to accurately perform rate-shaping could 
lead to substantial increases in emissions (primarily NOX or 
PM), often times with an associated change in fuel consumption.
b. Fuel System Monitoring Requirements
    We are proposing that the OBD system monitor the fuel delivery 
system to verify that it is functioning properly. The fuel system 
monitor would be required to monitor for malfunctions in the injection 
pressure control, injection quantity, injection timing, and feedback 
control (if equipped). The individual electronic components (e.g., 
actuators, valves, sensors, pumps) that are used in the fuel system and 
not specifically addressed in this section shall be monitored in 
accordance with the comprehensive component requirements in section 
II.D.4.
i. Fuel System Pressure Control
    We are proposing that the OBD system continuously monitor the fuel 
system's ability to control to the desired fuel pressure. The OBD 
system would have to detect a malfunction of the fuel system's pressure 
control system when

[[Page 3213]]

the pressure control system is unable to maintain an engine's emissions 
at or below the emissions thresholds for ``other monitors'' as shown in 
Table II.B-1. For engines in which no failure or deterioration of the 
fuel system pressure control could result in an engine's emissions 
exceeding the applicable emissions thresholds, the OBD system would be 
required to detect a malfunction when the system has reached its 
control limits such that the commanded fuel system pressure cannot be 
delivered.
ii. Fuel System Injection Quantity
    We are proposing that the OBD system detect a malfunction of the 
fuel injection system when the system is unable to deliver the 
commanded quantity of fuel necessary to maintain an engine's emissions 
at or below the emissions thresholds for ``other monitors'' as shown in 
Table II.B-1. For engines in which no failure or deterioration of the 
fuel injection quantity could result in an engine's emissions exceeding 
the applicable emissions thresholds, the OBD system would be required 
to detect a malfunction when the system has reached its control limits 
such that the commanded fuel quantity cannot be delivered.
iii. Fuel System Injection Timing
    We are proposing that the OBD system detect a malfunction of the 
fuel injection system when the system is unable to deliver fuel at the 
proper crank angle/timing (e.g., injection timing too advanced or too 
retarded) necessary to maintain an engine's emissions at or below the 
emissions thresholds for ``other monitors'' as shown in Table II.B-1. 
For engines in which no failure or deterioration of the fuel injection 
timing could result in an engine's emissions exceeding the applicable 
emissions thresholds, the OBD system would be required to detect a 
malfunction when the system has reached its control limits such that 
the commanded fuel injection timing cannot be achieved.
iv. Fuel System Feedback Control
    If the engine is equipped with feedback control of the fuel system 
(e.g., feedback control of pressure or pilot injection quantity), we 
are proposing that the OBD system detect a malfunction when and if:
     The system fails to begin feedback control within a 
manufacturer specified time interval;
     A failure or deterioration causes open loop or default 
operation; or
     Feedback control has used up all of the adjustment allowed 
by the manufacturer.
    A manufacturer may temporarily disable monitoring for malfunctions 
where the feedback control has used up all of the adjustment allowed by 
the manufacturer during conditions that the monitor cannot distinguish 
robustly between a malfunctioning system and a properly operating 
system. To do so, the manufacturer would be required to submit data 
and/or engineering analyses demonstrating that the control system, when 
operating as designed on an engine with all emission controls working 
properly, routinely operates during these conditions with all of the 
adjustment allowed by the manufacturer used up. In lieu of detecting, 
with a fuel system specific monitor, when the system fails to begin 
feedback control within a manufacturer specified time interval and/or 
when a failure or deterioration causes open loop or default operation, 
the OBD system may monitor the individual parameters or components that 
are used as inputs for fuel system feedback control provided that the 
monitors detect all malfunctions related to feedback control.
c. Fuel System Monitoring Conditions
    The OBD system would be required to monitor continuously for 
malfunctions of the fuel pressure control and feedback control. 
Manufacturers would be required to define the monitoring conditions for 
malfunctions of the injection quantity and injection timing such that 
the minimum performance ratio requirements discussed in section II.E 
would be met.
d. Fuel System MIL Illumination and DTC Storage
    We are proposing the general MIL illumination and DTC storage 
requirements as discussed in section II.A.2.
2. Engine Misfire Monitoring
a. Background
    Misfire, the lack of combustion in the cylinder, causes increased 
engine-out hydrocarbon emissions. On gasoline engines, misfire results 
from the absence of spark, poor fuel metering, and poor compression. 
Further, misfire can be intermittent on gasoline engines (e.g., the 
misfire only occurs under certain engine speeds or loads). 
Consequently, our existing under 14,000 pound OBD regulation requires 
continuous monitoring for misfire malfunctions on gasoline engines.
    In contrast, manufacturers have historically maintained that a 
diesel engine with traditional diesel technology misfires only due to 
poor compression (e.g., worn valves or piston rings, improper injector 
or glow plug seating). They have also maintained that, when poor 
compression results in a misfiring cylinder, the cylinder will misfire 
under all operating conditions rather than only some operating 
conditions. For that reason, our existing under 14,000 pound OBD 
regulation has not required continuous monitoring for misfire 
malfunctions on diesel engines.
    However, with the increased use of EGR and its use to varying 
degrees at different speeds and load, and with emerging technologies 
such as homogeneous charge compression ignition (HCCI), we believe that 
the conventional wisdom regarding diesel engines and misfires no longer 
holds true. These newer technologies may indeed result in misfires that 
are intermittent, spread out among various cylinders, and that only 
happen at certain speeds and loads.
b. Misfire Monitoring Requirements
    We are proposing that the OBD system monitor the engine for misfire 
causing excess emissions. The OBD system must be capable of detecting 
misfire occurring in one or more cylinders. To the extent possible 
without adding hardware for this specific purpose, the OBD system must 
also identify the specific misfiring cylinder. If more than one 
cylinder is continuously misfiring, a separate DTC must be stored 
indicating that multiple cylinders are misfiring. When identifying 
multiple cylinder misfire, the OBD system is not required to also 
identify each of the continuously misfiring cylinders individually 
through separate DTCs.
    For 2013 and subsequent model year engines, we are proposing a more 
stringent requirement that the OBD system detect a misfire malfunction 
causing emissions to exceed the emissions thresholds for ``other 
monitors'' as shown in Table II.B-1. This requirement to detect engine 
misfire prior to exceeding an emissions threshold would apply only to 
those engines equipped with sensors capable of detecting combustion or 
combustion quality (e.g., cylinder pressure sensors used in homogeneous 
charge compression ignition (HCCI) control systems). Engines without 
such sensors would have to detect only when one or more cylinders are 
continually misfiring.
    To determine what level of misfire would cause emissions to exceed 
the applicable emissions thresholds, we are proposing that 
manufacturers determine

[[Page 3214]]

the percentage of misfire evaluated in 1000 revolution increments that 
would cause emissions from an emission durability demonstration engine 
to exceed the emissions thresholds if the percentage of misfire were 
present from the beginning of the test. To establish this percentage of 
misfire, the manufacturer would utilize misfire events occurring at 
equally spaced, complete engine cycle intervals, across randomly 
selected cylinders throughout each 1000-revolution increment. If this 
percentage of misfire is determined to be lower than one percent, the 
manufacturer may set the malfunction criteria at one percent. Any 
malfunction should be detected if the percentage of misfire established 
via this testing is exceeded regardless of the pattern of misfire 
events (e.g., random, equally spaced, continuous).
    The manufacturer may employ other revolution increments besides the 
1000 revolution increment being proposed. To do so, the manufacturer 
would need to demonstrate that the strategy would be equally effective 
and timely in detecting misfire.
c. Engine Misfire Monitoring Conditions
    For engines without combustion sensors, we are proposing that the 
OBD system monitor for misfire during engine idle conditions at least 
once per drive cycle in which the monitoring conditions for misfire are 
met. The manufacturer would be required to define monitoring 
conditions, supported by manufacturer-submitted data and/or engineering 
analyses, that demonstrate that the monitoring conditions: are 
technically necessary to ensure robust detection of malfunctions (e.g., 
avoid false passes and false detection of malfunctions); require no 
more than 1000 cumulative engine revolutions; and, do not require any 
single continuous idle operation of more than 15 seconds to make a 
determination that a malfunction is present (e.g., a decision can be 
made with data gathered during several idle operations of 15 seconds or 
less).
    For 2013 and subsequent model year engines with combustion sensors, 
we are proposing that the OBD system continuously monitor for misfire 
under all positive torque engine speeds and load conditions. If a 
monitoring system cannot detect all misfire patterns under all positive 
torque engine speeds and load conditions, the manufacturer may request 
that the Administrator approve the monitoring system nonetheless. In 
evaluating the manufacturer's request, the Administrator would consider 
the following factors: the magnitude of the region(s) in which misfire 
detection is limited; the degree to which misfire detection is limited 
in the region(s) (i.e., the probability of detection of misfire 
events); the frequency with which said region(s) are expected to be 
encountered in-use; the type of misfire patterns for which misfire 
detection is troublesome; and demonstration that the monitoring 
technology employed is not inherently incapable of detecting misfire 
under required conditions (i.e., compliance can be achieved on other 
engines). The evaluation would be based on the following misfire 
patterns: equally spaced misfire occurring on randomly selected 
cylinders; single cylinder continuous misfire; and, paired cylinder 
(cylinders firing at the same crank angle) continuous misfire.
d. Engine Misfire MIL Illumination and DTC Storage
    For engines without combustion sensors, we are proposing the 
general MIL illumination and DTC storage requirements as discussed in 
section II.A.2.
    For 2013 and subsequent model year engines with combustion sensors, 
we are proposing that, after four detections of the percentage of 
misfire that would cause emissions to exceed the applicable emissions 
thresholds during a single driving cycle, a pending DTC would be 
stored. If a pending DTC is stored, the OBD system would be required to 
illuminate the MIL and store a MIL--on DTC if the percentage of misfire 
is again exceeded four times during either: the driving cycle 
immediately following the storage of the pending DTC, regardless of the 
conditions encountered during the driving cycle; or, the next driving 
cycle in which similar conditions are encountered to the engine 
conditions that occurred when the pending DTC was stored.\18\ For 
erasure of the pending DTC, we are proposing if, by the end of the next 
driving cycle in which similar conditions have been encountered to the 
engine conditions that occurred when the pending DTC was stored without 
an exceedance of the specified percentage of misfire, the pending DTC 
may be erased. The pending DTC may also be erased if similar conditions 
are not encountered during the next 80 driving cycles immediately 
following initial detection of the malfunction.
---------------------------------------------------------------------------

    \18\ ``Similar conditions,'' as used in conjunction with misfire 
and fuel system monitoring, means engine conditions having an engine 
speed within 375 rpm, load conditions within 20 percent, and the 
same warm up status (i.e., cold or hot) as existing during the 
applicable previous problem detection. The Administrator may approve 
other definitions of similar conditions based on comparable 
timeliness and reliability in detecting similar engine operation.
---------------------------------------------------------------------------

    We are proposing some specific items with respect to freeze frame 
storage associated with engine misfire. The OBD system shall store and 
erase freeze frame conditions either in conjunction with storing and 
erasing a pending DTC or in conjunction with storing a MIL--on DTC and 
erasing a MIL--on DTC. In addition to those proposed requirements 
discussed in section II.A.2, we are proposing that, if freeze frame 
conditions are stored for a malfunction other than a misfire 
malfunction when a DTC is stored, the previously stored freeze frame 
information shall be replaced with freeze frame information regarding 
the misfire malfunction (i.e., the misfire's freeze frame information 
should take precedence over freeze frames for other malfunctions). 
Further, we are proposing that, upon detection of misfire, the OBD 
system store the following engine conditions: engine speed, load, and 
warm up status of the first misfire event that resulted in the storage 
of the pending DTC.
    Lastly, we are proposing that the MIL may be extinguished after 
three sequential driving cycles in which similar conditions have been 
encountered without an exceedance of the specified percentage of 
misfire.
3. Exhaust Gas Recirculation (EGR) System Monitoring
a. Background
    Exhaust gas recirculation (EGR) systems are currently being used by 
many heavy-duty engine manufacturers to meet the 2.5 g/bhp-hr 
NOX+NMHC standard for 2004 and later model year engines. (65 
FR 59896) EGR reduces NOX emissions in several ways. First, 
the recirculated exhaust gases dilute the intake air--i.e., oxygen in 
the fresh air is displaced with relatively non-reactive exhaust gases--
which, in turn, results in less oxygen to form NOX. Second, 
EGR absorbs heat from the combustion process which reduces combustion 
chamber temperatures which, in turn, reduces NOX formation. 
The amount of heat absorbed from the combustion process is a function 
of EGR flow rate and recirculated gas temperature, both of which are 
controlled to minimize NOX emissions. An EGR cooler can be 
added to the EGR system to lower the recirculated gas temperature which 
further enhances NOX control. We fully expect that 2007 and 
later model year engines will continue to make use of cooled EGR 
systems.
    While in theory the EGR system simply routes some exhaust gas back 
to the intake, production systems can be complex and involve many 
components to ensure accurate control of EGR flow

[[Page 3215]]

to maintain acceptable PM and NOX emissions while minimizing 
effects on fuel economy. To control EGR flow rates, EGR systems 
normally use the following components: an EGR valve, valve position 
sensor, boost pressure sensor, intake temperature sensor, intake 
(fresh) airflow sensor, and tubing or piping to connect the various 
components of the system. EGR temperature sensors and exhaust 
backpressure sensors can also be used. Additionally, some systems use a 
variable geometry turbocharger to provide the backpressure necessary to 
drive the EGR flow. Therefore, EGR is not a stand alone emission 
control device. Rather, it is carefully integrated with the air 
handling system (turbocharging and intake cooling) to control 
NOX while not adversely affecting PM emissions and fuel 
economy.
b. EGR System Monitoring Requirements
    We are proposing that the OBD system monitor the EGR system on 
engines so equipped for low EGR flow rate, high EGR flow rate, and slow 
EGR flow response malfunctions. For engines so equipped, we are 
proposing that the EGR feedback control be monitored. Also, for engines 
equipped with EGR coolers (e.g., heat exchangers), the OBD system would 
have to monitor the cooler for malfunctions associated with 
insufficient EGR cooling. The individual electronic components (e.g., 
actuators, valves, sensors) that are used in the EGR system would be 
monitored in accordance with the comprehensive component requirements 
presented in section II.D.4.
i. EGR Low Flow Malfunctions
    We are proposing that the OBD system detect a malfunction prior to 
a decrease from the manufacturer's specified EGR flow rate that would 
cause an engine's emissions to exceed the emissions thresholds for 
``other monitors'' as shown in Table II.B-1. For engines in which no 
failure or deterioration of the EGR system that causes a decrease in 
flow could result in an engine's emissions exceeding the applicable 
emissions thresholds, the OBD system would have to detect a malfunction 
when the system has reached its control limits such that it cannot 
increase EGR flow to achieve the commanded flow rate.
ii. EGR High Flow Malfunctions
    We are proposing that the OBD system detect a malfunction of the 
EGR system, including a leaking EGR valve--i.e., exhaust gas flowing 
through the valve when the valve is commanded closed--prior to an 
increase from the manufacturer's specified EGR flow rate that would 
cause an engine's emissions to exceed the emissions thresholds for 
``other monitors'' as shown in Table II.B-1. For engines in which no 
failure or deterioration of the EGR system that causes an increase in 
flow could result in an engine's emissions exceeding the applicable 
emissions thresholds, the OBD system would have to detect a malfunction 
when the system has reached its control limits such that it cannot 
reduce EGR flow to achieve the commanded flow rate.
iii. EGR Slow Response Malfunctions
    We are proposing that the OBD system detect a malfunction of the 
EGR system prior to any failure or deterioration in the capability of 
the EGR system to achieve the commanded flow rate within a 
manufacturer-specified time that would cause an engine's emissions to 
exceed the emissions thresholds for ``other monitors'' as shown in 
Table II.B-1. The OBD system would have to monitor both the capability 
of the EGR system to respond to a commanded increase in flow and the 
capability of the EGR system to respond to a commanded decrease in 
flow.
iv. EGR Feedback Control
    We are proposing that the OBD system on any engine equipped with 
feedback control of the EGR system (e.g., feedback control of flow, 
valve position, pressure differential across the valve via intake 
throttle or exhaust backpressure), detect a malfunction when and if:
     The system fails to begin feedback control within a 
manufacturer specified time interval;
     A failure or deterioration causes open loop or default 
operation; or
     Feedback control has used up all of the adjustment allowed 
by the manufacturer.
v. EGR Cooler Performance
    We are proposing that the OBD system detect a malfunction of the 
EGR cooler prior to a reduction from the manufacturer's specified 
cooling performance that would cause an engine's emissions to exceed 
the emissions thresholds for ``other monitors'' as shown in Table II.B-
1. For engines in which no failure or deterioration of the EGR cooler 
could result in an engine's emissions exceeding the applicable 
emissions thresholds, the OBD system would have to detect a malfunction 
when the system has no detectable amount of EGR cooling.
c. EGR System Monitoring Conditions
    We are proposing that the OBD system monitor continuously for low 
EGR flow, high EGR flow, and feedback control malfunctions. 
Manufacturers would be required to define the monitoring conditions for 
EGR slow response malfunctions such that the minimum performance ratio 
requirements discussed in section II.E would be met with the exception 
that monitoring must occur every time the monitoring conditions are met 
during the driving cycle in lieu of once per driving cycle as required 
for most monitors. For purposes of tracking and reporting as required 
in section II.E, all monitors used to detect EGR slow response 
malfunctions must be tracked separately but reported as a single set of 
values as specified in section II.E.\19\
---------------------------------------------------------------------------

    \19\ For specific components or systems that have multiple 
monitors that are required to be reported (e.g., exhaust gas sensor 
bank 1 may have multiple monitors for sensor response or other 
sensor characteristics), the OBD system must separately track 
numerators and denominators for each of the specific monitors and 
report only the corresponding numerator and denominator for the 
specific monitor that has the lowest numerical ratio. If two or more 
specific monitors have identical ratios, the corresponding numerator 
and denominator for the specific monitor that has the highest 
denominator shall be reported for the specific component.
---------------------------------------------------------------------------

    Manufacturersmay temporarily disable the EGR system check under 
specific conditions (e.g., when freezing may affect performance of the 
system). To do so, the manufacturer would be required to submit data 
and/or engineering analyses that demonstrate that a reliable check 
cannot be made when these specific conditions exist.
d. EGR System MIL Illumination and DTC Storage
    We are proposing the general requirements for MIL illumination and 
DTC storage as discussed in section II.A.2.
4. Turbo Boost Control System Monitoring
a. Background
    Turbochargers are used on internal combustion engines to enhance 
performance by increasing the density of the intake air. Some of the 
benefits of turbocharging include increased horsepower, improved fuel 
economy, and decreased exhaust smoke. Most modern diesel engines take 
advantage of these benefits and are equipped with turbocharging 
systems. Moreover, smaller turbocharged diesel engines can be used in 
place of larger non-turbocharged engines to achieve the desired engine 
performance characteristics.

[[Page 3216]]

    Exhaust gases passing through the turbine cause it to spin which, 
in turn, causes an adjacent centrifugal pump on the same rotating shaft 
to spin. The spinning pump serves to compress the intake air thereby 
increasing its density. Typically, a boost pressure sensor is located 
in the intake manifold to provide a feedback signal of the current 
intake manifold pressure. As turbo speed (boost) increases, the 
pressure in the intake manifold also increases.
    Proper boost control is essential to optimize emission levels. Even 
short periods of over-or under-boost can result in undesired air-fuel 
ratio excursions and corresponding emission increases. Additionally, 
the boost control system directly affects exhaust and intake manifold 
pressures. Another critical emission control system, EGR, is very 
dependent on these two pressures and generally uses the differential 
between them to force exhaust gas into the intake manifold. If the 
boost control system is not operating correctly, the exhaust or intake 
pressures may not be as expected and the EGR system may not function as 
designed. In high-pressure EGR systems, higher exhaust pressures will 
generate more EGR flow and, conversely, lower pressures will reduce EGR 
flow. A malfunction that causes excessive exhaust pressures (e.g., 
wastegate stuck closed at high engine speed) can produce higher EGR 
flowrates at high load conditions and have a negative impact on 
emissions.
    Manufacturers commonly use charge air coolers to maximize the 
benefits of turbocharging and to control NOX emissions. As 
the turbocharger compresses the intake air, the temperature of that 
intake air increases. This increasing air temperature causes the air to 
expand, which conflicts with one of the goals of turbocharging which is 
to increase charge air density. Charge air coolers are used to exchange 
heat between the compressed air and ambient air (or coolant) and cool 
the compressed air. Accordingly, a decrease in charge air cooler 
performance can affect emissions by causing higher intake air 
temperatures that can lead to higher combustion temperatures and higher 
NOX emissions.
    One drawback of turbocharging is known as turbo lag. Turbo lag 
occurs when the driver attempts to accelerate quickly from a low engine 
speed. Since the turbocharger is a mechanical device, a delay exists 
from the driver demand for more boost until the exhaust flow can 
physically speed up the turbocharger enough to deliver that boost. In 
addition to a negative effect on driveability and performance, improper 
fueling (e.g., over-fueling) during this lag can cause emission 
increases (typically PM).
    To decrease the effects of turbo lag, manufacturers design turbos 
that spool up quickly at low engine speeds and low exhaust flowrates. 
However, designing a turbo that will accelerate quickly from a low 
engine speed but will not result in an over-speed/over-boost condition 
at higher engine speeds is challenging. That is, as the engine speed 
and exhaust flowrates near their maximum, the turbo speed increases to 
levels that cause excessive boost pressures and heat that could lead to 
engine or turbo damage. To prevent excessive turbine speeds and boost 
pressures at higher engine speeds, a wastegate is often used to bypass 
part of the exhaust stream around the turbocharger. The wastegate valve 
is typically closed at lower engine speeds so that all exhaust is 
directed through the turbocharger, thus providing quick response from 
the turbocharger when the driver accelerates quickly from low engine 
speeds. The wastegate is then opened at higher engine speeds to prevent 
engine or turbo damage from an over-speed condition.
    An alternative to a wastegate is the variable geometry 
turborcharger (VGT). To prevent over-boost conditions and to decrease 
turbo lag, VGTs are designed such that the geometry of the turbocharger 
changes with engine speed. While various physical mechanisms are used 
to achieve the variable geometry, the overall result is essentially the 
same. At low engine speeds, the exhaust gas into the turbo is 
restricted in a manner that maximizes the use of the available energy 
to spin the turbo. This allows the turbo to spool up quickly and 
provide good acceleration response. At higher engine speeds, the turbo 
geometry changes such that exhaust gas flow into the turbo is not as 
restricted. In this configuration, more exhaust can flow through the 
turbocharger without causing an over-speed condition. The advantage 
that VGTs offer compared to a waste-gated turbocharger is that all 
exhaust flow is directed through the turbocharger under all operating 
conditions. This can be viewed as maximizing the use of the available 
exhaust energy.
b. Turbo Boost Control System Monitoring Requirements
    We are proposing that the OBD system monitor the boost pressure 
control system on engines so equipped for under and over boost 
malfunctions. For engines equipped with variable geometry turbochargers 
(VGT), the OBD system would have to monitor the VGT system for slow 
response malfunctions. For engines equipped with charge air cooler 
systems, the OBD system would have to monitor the charge air cooler 
system for cooling system performance malfunctions. The individual 
electronic components (e.g., actuators, valves, sensors) that are used 
in the boost pressure control system shall be monitored in accordance 
with the comprehensive component requirements in section II.D.4.
i. Turbo Underboost Malfunctions
    We are proposing that the OBD system detect a malfunction of the 
boost pressure control system prior to a decrease from the 
manufacturer's commanded boost pressure that would cause an engine's 
emissions to exceed the emissions thresholds for ``other monitors'' as 
shown in Table II.B-1. For engines in which no failure or deterioration 
of the boost pressure control system that causes a decrease in boost 
could result in an engine's emissions exceeding the applicable 
emissions thresholds, the OBD system must detect a malfunction when the 
system has reached its control limits such that it cannot increase 
boost to achieve the commanded boost pressure.
ii. Turbo Overboost Malfunctions
    We are proposing that the OBD system detect a malfunction of the 
boost pressure control system prior to an increase from the 
manufacturer's commanded boost pressure that would cause an engine's 
emissions to exceed the emissions thresholds for ``other monitors'' as 
shown in Table II.B-1. For engines in which no failure or deterioration 
of the boost pressure control system that causes an increase in boost 
could result in an engine's emissions exceeding the applicable 
emissions thresholds, the OBD system must detect a malfunction when the 
system has reached its control limits such that it cannot decrease 
boost to achieve the commanded boost pressure.
iii. VGT Slow Response Malfunctions
    We are proposing that the OBD system detect a malfunction prior to 
any failure or deterioration in the capability of the VGT system to 
achieve the commanded turbocharger geometry within a manufacturer-
specified time that would cause an engine's emissions to exceed the 
emissions thresholds for ``other monitors'' as shown in Table II.B-1. 
For engines in which no failure or deterioration of the VGT system 
response could result in an engine's emissions exceeding the applicable 
emissions thresholds, the OBD system must detect a malfunction of the 
VGT system when proper functional response

[[Page 3217]]

of the system to computer commands does not occur.
iv. Turbo Boost Feedback Control Malfunctions
    We are proposing that, for engines equipped with feedback control 
of the boost pressure system--e.g., control of VGT position, turbine 
speed, manifold pressure--the OBD system shall detect a malfunction 
when and if:
     The system fails to begin feedback control within a 
manufacturer specified time interval;
     A failure or deterioration causes open loop or default 
operation; or
     Feedback control has used up all of the adjustment allowed 
by the manufacturer.
v. Charge Air Undercooling Malfunctions
    We are proposing that the OBD system detect a malfunction of the 
charge air cooling system prior to a decrease from the manufacturer's 
specified cooling rate that would cause an engine's emissions to exceed 
the emissions thresholds for ``other monitors'' as shown in Table II.B-
1. For engines in which no failure or deterioration of the charge air 
cooling system that causes a decrease in cooling performance could 
result in an engine's emissions exceeding the applicable emissions 
thresholds, the OBD system must detect a malfunction when the system 
has no detectable amount of charge air cooling.
c. Turbo Boost Control System Monitoring Conditions
    We are proposing that the OBD system monitor continuously for 
underboost and overboost malfunctions and for boost feedback control 
malfunctions. Manufacturers would be required to define the monitoring 
conditions for VGT slow response malfunctions such that the minimum 
performance ratio requirements discussed in section II.E would be met 
with the exception that monitoring must occur every time the monitoring 
conditions are met during the driving cycle in lieu of once per driving 
cycle as required for most monitors. For purposes of tracking and 
reporting as required in section II.E, all monitors used to detect VGT 
slow response malfunctions malfunctions must be tracked separately but 
reported as a single set of values as discussed in section II.E.\20\
---------------------------------------------------------------------------

    \20\ For specific components or systems that have multiple 
monitors that are required to be reported (e.g., exhaust gas sensor 
bank 1 may have multiple monitors for sensor response or other 
sensor characteristics), the OBD system must separately track 
numerators and denominators for each of the specific monitors and 
report only the corresponding numerator and denominator for the 
specific monitor that has the lowest numerical ratio. If two or more 
specific monitors have identical ratios, the corresponding numerator 
and denominator for the specific monitor that has the highest 
denominator shall be reported for the specific component.
---------------------------------------------------------------------------

d. Turbo Boost MIL Illumination and DTC Storage
    We are proposing the general MIL illumination and DTC storage 
requirements as discussed in section II.A.2.
5. Non-Methane Hydrocarbon (NMHC) Converting Catalyst Monitoring
a. Background
    Diesel oxidation catalysts (DOCs) have been used on some nonroad 
diesel engines since the 1960s and on some diesel trucks and buses in 
the U.S. since the early 1990s. DOCs are generally used for converting 
HC and carbon monoxide (CO) emissions to water and CO2 via 
an oxidation process. Current DOCs can also be used to convert PM 
emissions. DOCs may also be used in conjunction with other 
aftertreatment emission controls--such as NOX adsorber 
systems, selective catalytic reduction (SCR) systems, and PM filters--
to improve their performance and/or clean up certain reducing agents 
that might slip through the system (e.g., the urea used in urea SCR 
systems).
b. NMHC Converting Catalyst Monitoring Requirements
    We are proposing that the OBD system monitor the NMHC converting 
catalyst(s) for proper NMHC conversion capability. We are also 
proposing that each catalyst that converts NMHC be monitored either 
individually or in combination with others. For engines equipped with 
catalyzed diesel particulate filters (CDPFs) that convert NMHC 
emissions, the catalyst function of the CDPF must be monitored in 
accordance with the CDPF monitoring requirements in section II.B.8.
i. NMHC Converting Catalyst Conversion Efficiency
    We are proposing that the OBD system detect an NMHC catalyst 
malfunction when the catalyst conversion capability decreases to the 
point that NMHC emissions exceed the emissions thresholds for ``NMHC 
catalysts'' as shown in Table II.B-1. If no failure or deterioration of 
the catalyst NMHC conversion capability could result in an engine's 
NMHC emissions exceeding the applicable emissions thresholds, the OBD 
system would have to detect a malfunction when the catalyst has no 
detectable amount of NMHC conversion capability.
ii. Other Aftertreatment Assistance Functions
    For catalysts used to generate an exotherm to assist CDPF 
regeneration, we are proposing that the OBD system detect a malfunction 
when the catalyst is unable to generate a sufficient exotherm to 
achieve that regeneration. For catalysts used to generate a feedgas 
constituency to assist SCR systems (e.g., to increase NO2 
concentration upstream of an SCR system), the OBD system would have to 
detect a malfunction when the catalyst is unable to generate the 
necessary feedgas constituents for proper SCR system operation. For 
catalysts located downstream of a CDPF and used to convert NMHC 
emissions during a CDPF regeneration event, the OBD system would be 
required to detect a malfunction when the catalyst has no detectable 
amount of NMHC conversion capability.
c. NMHC Converting Catalyst Monitoring Conditions
    Manufacturers would be required to define the monitoring conditions 
for NMHC converting catalyst malfunctions such that the minimum 
performance ratio requirements discussed in section II.E would be met. 
For purposes of tracking and reporting as discussed in section II.E, 
all monitors used to detect NMHC converting catalyst malfunctions must 
be tracked separately but reported as a single set of values as 
discussed in section II.E.\21\
---------------------------------------------------------------------------

    \21\ For specific components or systems that have multiple 
monitors that are required to be reported (e.g., exhaust gas sensor 
bank 1 may have multiple monitors for sensor response or other 
sensor characteristics), the OBD system must separately track 
numerators and denominators for each of the specific monitors and 
report only the corresponding numerator and denominator for the 
specific monitor that has the lowest numerical ratio. If two or more 
specific monitors have identical ratios, the corresponding numerator 
and denominator for the specific monitor that has the highest 
denominator shall be reported for the specific component.
---------------------------------------------------------------------------

d. NMHC Converting Catalyst MIL Illumination and DTC Storage
    We are proposing the general requirements for MIL illumination and 
DTC storage discussed in section II.A.2. Note that the monitoring 
method for the catalyst(s) must be capable of detecting all instances, 
except diagnostic self-clearing, when a catalyst DTC has been cleared 
but the catalyst has not been replaced (e.g., catalyst over temperature 
histogram approaches are not acceptable).\22\
---------------------------------------------------------------------------

    \22\ For gasoline catalyst monitoring, manufacturers generally 
use what is called an exponentially weighted moving average (EWMA) 
approach to making decisions about the catalyst's pass/fail status. 
This approach monitors the catalyst and ``saves'' that information. 
The next time it monitors the catalyst, it saves that information 
along with the previous information, placing a higher weighting on 
the most recent information. This is done every time the OBD system 
monitors the catalyst and the EWMA saves six or seven monitoring 
events before making a decision. Importantly, once there exists six 
or seven pieces of information, every monitoring event can result in 
a decision because the EWMA is always using the previous six or 
seven events. Unfortunately, if a service technician clears the data 
with a scan tool, it is going to take six or seven monitoring events 
before the catalyst monitor can make a decision on the pass/fail 
status of the catalyst. So, we want to be sure that, in addition to 
the EWMA aspect of the catalyst monitor, there exists a way of 
determining quickly that someone has cleared the data but perhaps 
did not actually repair the catalyst. This is required to help 
prevent against DTC clearing without fixing a failed catalyst as a 
means of passing an inspection & maintenance test.

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[[Page 3218]]

6. Selective Catalytic Reduction (SCR) and Lean NOX Catalyst 
Monitoring
a. Background
    Selective Catalytic Reduction (SCR) catalysts that use ammonia as a 
NOX reductant have been used for stationary source 
NOX control for a number of years. Frequently, urea is used 
as the source of ammonia for SCR catalysts, and such systems are 
commonly referred to as Urea SCR systems. In recent years, considerable 
effort has been invested in developing urea SCR systems that could be 
applied to heavy-duty diesel vehicles with low sulfur diesel fuel. We 
now expect that urea SCR systems will be introduced in Europe to comply 
with the EURO IV heavy-duty diesel emission standards. Such systems 
have been introduced in the past year by some heavy-duty diesel engine 
manufacturers both in Europe and in Japan.
    SCR catalyst systems require an accurate urea control system to 
inject precise amounts of reductant. An injection rate that is too low 
may result in lower NOX conversions while an injection that 
is too high may release unwanted ammonia emissions--referred to as 
ammonia slip--to the atmosphere. In general, ammonia to NOX 
ratios of around 1:1 are used to provide the highest NOX 
conversion rates with minimal ammonia slip. Therefore, injecting just 
the right amount of ammonia appropriate for the amount of 
NOX in the exhaust is very important. This can be 
challenging in a highway application because on-road diesel engines 
operate over a variety of speeds and loads. This makes the use of 
closed-loop feedback systems for reductant metering very attractive. 
This can be achieved, for example, with a dedicated NOX 
sensor in the exhaust so that the NOX concentration can be 
accurately known. With an accurate fast response NOX sensor, 
closed-loop control of the ammonia injection can be used to achieve and 
maintain the desired ammonia/NOX ratios in the SCR catalyst 
for the high NOX conversion efficiencies necessary to 
achieve the 2010 emission standards under various engine operating 
conditions.
    Some have estimated that achieving the 2010 NOX emission 
standards with SCR systems will require NOX sensors that can 
measure NOX levels accurately in the 20 to 40 ppm range with 
little cross sensitivity to ammonia. Some in industry have even stated 
a desire for accuracy in the two to three ppm range. Suppliers have 
been developing NOX sensors capable of measuring 
NOX in the 0 to 100 ppm range with +/-5 ppm accuracy which 
we believe will be available by 2010.\23\ Regarding cross-sensitivity 
to ammonia, work has been done that indicates ammonia and 
NOX measurements can be independently measured by 
conditioning the output signal.\24\ This signal conditioning method 
resulted in a linear output for both ammonia and NOX from 
the NOX sensor downstream of the catalyst.
---------------------------------------------------------------------------

    \23\ Draft Technical Support Document, HDOBD NPRM, EPA420-D-06-
006, Docket ID EPA-HQ-OAR-2005-0047-0008.
    \24\ Schaer, C. M., Onder, C. H., Geering, H. P., and Elsener, 
M., ``Control of a Urea SCR Catalytic Converter System for a Mobile 
Heavy-Duty Diesel Engine,'' SAE Paper 2003-01-0776 which may be 
obtained from Society of Automotive Engineers International, 400 
Commonwealth Dr., Warrendale, PA, 15096-0001.
---------------------------------------------------------------------------

    For SCR systems, closed-loop control of the reductant injection may 
require the use of two NOX sensors. The first NOX 
sensor would be located upstream of the catalyst and the reductant 
injection point would be used for measuring the engine-out 
NOX emissions and determining the amount of reductant 
injection needed to reduce emissions. The second NOX sensor 
located downstream of the catalyst would be used for measuring the 
amount of ammonia and NOX emissions exiting the catalyst and 
providing feedback to the reductant injection control system. If the 
downstream NOX sensor detects too much NOX 
emissions exiting the catalyst, the control system can inject higher 
quantities of reductant. Conversely, if the downstream NOX 
sensor detects too much ammonia slip exiting the catalyst, the control 
system can decrease the amount of reductant injection.
    In addition to exhaust NOX levels, another important 
parameter for achieving high NOX conversion rates with 
minimum ammonia slip is catalyst temperature. SCR catalysts have a 
defined temperature range where they are most effective. For example, 
platinum catalysts are effective between 175 and 250 degrees Celsius, 
vanadium catalysts are effective between 300 and 450 degrees Celsius, 
and zeolite catalysts are most effective between 350 and 600 degrees 
Celsius. To determine exhaust catalyst temperature for reductant 
control purposes, manufacturers are likely to use temperature sensors 
placed in the exhaust system. We project that only one temperature 
sensor positioned just downstream of the SCR system will be utilized 
for reductant injection control purposes.
    Production SCR catalyst systems may also contain auxiliary 
catalysts to improve the overall emissions control capability of the 
system. An oxidation catalyst is often positioned downstream of the SCR 
catalyst to help control ammonia slip on systems without closed-loop 
control of ammonia injection. The use of a ``guard'' catalyst could 
allow higher ammonia injection levels, thereby increasing the 
NOX conversion efficiency without releasing un-reacted 
ammonia into the exhaust. The guard catalyst can also reduce HC and CO 
emission levels and diesel odors. However, increased N2O emissions may 
occur and NOX emission levels may actually increase if too 
much ammonia is oxidized in the catalyst. Some SCR systems may also 
include an oxidation catalyst upstream of the SCR catalyst and urea 
injection point to generate NO2 for lowering the effective operating 
temperature and/or volume of the SCR catalyst. Studies have indicated 
that increasing the NO2 content in the exhaust stream can reduce the 
SCR temperature requirements by about 100 degrees Celsius.\25\ This 
``pre-oxidation'' catalyst also has the added benefit of reducing HC 
emissions.
---------------------------------------------------------------------------

    \25\ Walker, A. P., Chandler, G. R., Cooper, B. J., et al., ``An 
Integrated SCR and Continuously Regenerating Trap System to Meet 
Future NOX and PM Legislation,'' SAE Paper 2000-01-0188 
which may be obtained from Society of Automotive Engineers 
International, 400 Commonwealth Dr., Warrendale, PA, 15096-0001.
---------------------------------------------------------------------------

b. SCR and Lean NOX Catalyst Monitoring Requirements
    We are proposing that the OBD system monitor SCR catalysts and lean 
NOX catalysts for proper conversion capability. We are also 
proposing that each catalyst that converts NOX be monitored 
either individually or in combination with others. For engines equipped 
with SCR systems or other catalyst systems that utilize an active/
intrusive reductant injection (e.g., active lean NOX 
catalysts utilizing diesel fuel

[[Page 3219]]

injection), the OBD system would be required to monitor the active/
intrusive reductant injection system for proper performance. The 
individual electronic components (e.g., actuators, valves, sensors, 
heaters, pumps) in the active/intrusive reductant injection system must 
be monitored in accordance with the comprehensive component 
requirements in section II.D.4.
i. Catalyst Conversion Efficiency Malfunctions
    We are proposing that the OBD system detect a catalyst malfunction 
when the catalyst conversion capability decreases to the point that 
would cause an engine's NOX emissions to exceed any of the 
applicable emissions thresholds for ``NOX Catalyst Systems'' 
as shown in Table II.B-1. If no failure or deterioration of the 
catalyst NOX conversion capability could result in an 
engine's NOX emissions exceeding any of the applicable 
emissions thresholds, the OBD system would have to detect a malfunction 
when the catalyst has no detectable amount of NOX conversion 
capability.
ii. Active/Intrusive Reductant Injection System Malfunctions
    Specific to SCR and other active/intrusive reductant injection 
system performance, we are proposing that the OBD system detect a 
malfunction prior to any failure or deterioration of the system to 
regulate reductant delivery properly (e.g., urea injection, separate 
injector fuel injection, post injection of fuel, air assisted 
injection/mixing) that would cause an engine's NOX emissions 
to exceed any of the applicable emissions thresholds for 
``NOX Catalyst Systems'' as shown in Table II.B-1. As above, 
if no failure or deterioration of the reductant delivery system could 
result in an engine's NOX emissions exceeding the applicable 
emissions thresholds, the OBD system would have to detect a malfunction 
when the system has reached its control limits such that it is no 
longer able to deliver the desired quantity of reductant.
    If the system uses a reductant other than the fuel used for the 
engine or uses a reservoir/tank for the reductant that is separate from 
the fuel tank used for the engine, the OBD system must detect a 
malfunction when there is no longer sufficient reductant available 
(e.g., the reductant tank is empty). If the system uses a reservoir/
tank for the reductant that is separate from the fuel tank used for the 
engine, the OBD system must detect a malfunction when an improper 
reductant is used in the reductant reservoir/tank (e.g., the reductant 
tank is filled with something other than the proper reductant).
iii. SCR and Lean NOX Catalyst Feedback Control System 
Malfunctions
    If the engine is equipped with feedback control of the reductant 
injection, we are proposing that the OBD system detect a malfunction 
when and if:
     The system fails to begin feedback control within a 
manufacturer specified time interval;
     A failure or deterioration causes open loop or default 
operation; or
     Feedback control has used up all of the adjustment allowed 
by the manufacturer.
c. SCR and Lean NOX Catalyst Monitoring Conditions
    Manufacturers would be required to define the monitoring conditions 
for catalyst conversion efficiency malfunctions such that the minimum 
performance ratio requirements discussed in section II.E would be met. 
For purposes of tracking and reporting as required in section II.E, all 
monitors used to detect catalyst conversion efficiency malfunctions 
must be tracked separately but reported as a single set of values as 
specified in section II.E.\26\ We are also proposing that the OBD 
system monitor continuously for active/intrusive reductant injection 
system malfunctions. Manufacturers would be required to monitor 
continuously the active/intrusive reductant delivery system.
---------------------------------------------------------------------------

    \26\ For specific components or systems that have multiple 
monitors that are required to be reported (e.g., exhaust gas sensor 
bank 1 may have multiple monitors for sensor response or other 
sensor characteristics), the OBD system must separately track 
numerators and denominators for each of the specific monitors and 
report only the corresponding numerator and denominator for the 
specific monitor that has the lowest numerical ratio. If two or more 
specific monitors have identical ratios, the corresponding numerator 
and denominator for the specific monitor that has the highest 
denominator shall be reported for the specific component.
---------------------------------------------------------------------------

d. SCR and Lean NOX Catalyst MIL Illumination and DTC 
Storage
    We are proposing the general MIL illumination and DTC storage 
requirements presented in section II.A.2 with the exception of active/
intrusive reductant injection related malfunctions. If the OBD system 
is capable of discerning that a system malfunction is being caused by 
an empty reductant tank, the manufacturer may delay illumination of the 
MIL if the vehicle is equipped with an alternative indicator for 
notifying the vehicle operator of the malfunction. The manufacturer 
would be required to demonstrate that: The alternative indicator is of 
sufficient illumination and location to be readily visible to the 
operator under all lighting conditions; and the alternative indicator 
provides equivalent assurance that a vehicle operator will be promptly 
notified; and, that corrective action would be undertaken. If the 
vehicle is not equipped with an alternative indicator and the MIL 
illuminates, the MIL may be immediately extinguished and the 
corresponding DTC erased once the OBD system has verified that the 
reductant tank has been properly refilled and the MIL has not been 
illuminated for any other type of malfunction. The Administrator may 
approve other strategies that provide equivalent assurance that a 
vehicle operator will be promptly notified and that corrective action 
will be undertaken.
    The monitoring method for the catalyst(s) would have to be capable 
of detecting all instances, except diagnostic self-clearing, when a 
catalyst DTC has been cleared but the catalyst has not been replaced 
(e.g., catalyst over temperature histogram approaches are not 
acceptable).
7. NOX Adsorber System Monitoring
a. Background
    NOX adsorbers, or lean NOX traps (LNT), work 
to control NOX emissions by storing NOX on the 
surface of the catalyst during the lean engine operation typical of 
diesel engines and then by undergoing subsequent brief rich 
regeneration events where the NOX is released and reduced 
across a precious metal catalyst.
    NOX adsorber systems generally consist of a conventional 
three-way catalyst function (e.g., platinum) with NOX 
storage components (i.e., adsorbents) incorporated into the washcoat. 
Three-way catalysts convert NOX emissions as well as HC and 
CO emissions (hence the name three-way) by promoting oxidation of HC 
and CO to H2O and CO2 using the oxidation 
potential of the NOX pollutant and, in the process, reducing 
the NOX emissions to nitrogen, N2. Said another 
way, three-way catalysts work with exhaust conditions where the net 
oxidizing and reducing chemistry of the exhaust is approximately equal, 
allowing the catalyst to promote complete oxidation/reduction reactions 
to the desired exhaust components of CO2, H2O, 
and N2. The oxidizing potential in the exhaust comes from 
NOX emissions and any feedgas oxygen (O2) not 
consumed during combustion. The reducing potential in the exhaust

[[Page 3220]]

comes from HC and CO emissions, which represent products of incomplete 
combustion. Operation of the engine to ensure that the oxidizing and 
reducing potential of the combustion and exhaust conditions is 
precisely balanced is referred to as stoichiometric engine operation.
    Because diesel engines run lean of stoichiometric operation, the 
NOX emissions are stored, or absorbed--via chemical reaction 
with alkaline earth metals such as barium nitrate in the washcoat--and 
then released during rich operation for conversion to N2. 
This NOX release during rich operation is referred to as a 
regeneration event. The rich operating conditions required for 
NOX regeneration, which generally last for several seconds, 
are typically achieved using a combination of intake air throttling (to 
reduce the amount of intake air), exhaust gas recirculation, and post-
combustion fuel injection.
    NOX adsorber systems have demonstrated NOX 
reduction efficiencies from 50 percent to in excess of 90 percent. This 
efficiency has been found to be highly dependent on the fuel sulfur 
content because NOX adsorbers are extremely sensitive to 
sulfur. The NOX adsorption material has an even greater 
affinity for sulfur compounds than NOX. Thus, sulfur 
compounds can saturate the adsorber and limit the number of active 
sites for NOX adsorption, thereby lowering the 
NOX reduction efficiency. Accordingly, low sulfur fuel is 
required to achieve the greatest NOX reduction efficiencies. 
Although new adsorber washcoat materials are being developed with a 
higher resistance to sulfur poisoning and ultra-low sulfur fuel will be 
the norm by 2010, NOX adsorber systems will still need to 
purge the stored sulfur from the storage bed by a process referred to 
as desulfation. Because the desulfation process takes longer (e.g., 
several minutes) and requires more fuel and heat than the 
NOX regeneration step, permanent thermal degradation of the 
NOX adsorber and fuel economy penalties may result from 
desulfation events happening with excessive frequency. However, if 
desulfation is not done frequently enough, NOX storage 
capacity would be compromised and fuel economy penalties would be 
incurred from excessive attempts at NOX regeneration.
    In order to achieve and maintain high NOX conversion 
efficiencies while limiting negative impacts on fuel economy and 
driveability, vehicles with NOX adsorber systems will 
require precise air/fuel control in the engine and in the exhaust 
stream. Diesel manufacturers are expected to utilize NOX 
sensors and temperature sensors to provide the most precise closed-loop 
control for the NOX adsorber system. If NOX 
sensors are not used to control the NOX adsorber system, 
manufacturers could use wide-range air-fuel (A/F) sensors located 
upstream and downstream of the adsorber as a substitute. However, A/F 
sensors cannot provide an instantaneous indication of tailpipe 
NOX levels, which would allow the control system to 
precisely determine when the adsorber system is filled to capacity and 
regeneration should be initiated. If A/F sensors are used in lieu of 
NOX sensors, an estimation of engine-out NOX 
emissions and their subsequent storage in the NOX adsorber 
can be achieved indirectly through modeling.
b. NOX Adsorber System Monitoring Requirements
    We are proposing that the OBD system monitor the NOX 
adsorber on engines so equipped for proper performance. For engines 
equipped with active/intrusive injection (e.g., in-exhaust fuel and/or 
air injection) to achieve NOX regeneration, the OBD system 
would have to monitor the active/intrusive injection system for proper 
performance. The individual electronic components (e.g., injectors, 
valves, sensors) that are used in the active/intrusive injection system 
would have to be monitored in accordance with the comprehensive 
component requirements in section II.D.4.
i. NOX Adsorber Capability Malfunctions
    We are proposing that the OBD system detect a NOX 
adsorber malfunction when its capability--i.e., its combined adsorption 
and conversion capability--decreases to the point that would cause an 
engine's NOX emissions to exceed the applicable emissions 
thresholds for ``NOX Catalyst Systems'' as shown in Table 
II.B-1. If no failure or deterioration of the NOX adsorber 
capability could result in an engine's NOX emissions 
exceeding the applicable emissions thresholds, the OBD system would 
have to detect a malfunction when the system has no detectable amount 
of NOX adsorber capability.
ii. Active/Intrusive Reductant Injection System Malfunctions
    For NOX adsorber systems that use active/intrusive 
injection (e.g., in-cylinder post fuel injection, in-exhaust air-
assisted fuel injection) to achieve desorption of the NOX 
adsorber, the OBD system would have to detect a malfunction if any 
failure or deterioration of the injection system's ability to properly 
regulate injection causes the system to be unable to achieve desorption 
of the NOX adsorber.
iii. NOX Adsorber Feedback Control System Malfunctions
    If the engine is equipped with feedback control of the reductant 
injection (e.g., feedback control of injection quantity, time), we are 
proposing that the OBD system detect a malfunction when and if:
     The system fails to begin feedback control within a 
manufacturer specified time interval;
     A failure or deterioration causes open loop or default 
operation; or
     Feedback control has used up all of the adjustment allowed 
by the manufacturer.
c. NOX Adsorber System Monitoring Conditions
    We are proposing that manufacturers define the monitoring 
conditions for NOX adsorber capability malfunctions such 
that the minimum performance ratio requirements discussed in section 
II.E would be met. For purposes of tracking and reporting as required 
in section II.E, all monitors used to detect NOX adsorber 
capability malfunctions must be tracked separately but reported as a 
single set of values as specified in section II.E.\27\ We are also 
proposing that the OBD system monitor continuously for active/intrusive 
reductant injection and feedback control system malfunctions.
---------------------------------------------------------------------------

    \27\ For specific components or systems that have multiple 
monitors that are required to be reported (e.g., exhaust gas sensor 
bank 1 may have multiple monitors for sensor response or other 
sensor characteristics), the OBD system must separately track 
numerators and denominators for each of the specific monitors and 
report only the corresponding numerator and denominator for the 
specific monitor that has the lowest numerical ratio. If two or more 
specific monitors have identical ratios, the corresponding numerator 
and denominator for the specific monitor that has the highest 
denominator shall be reported for the specific component.
---------------------------------------------------------------------------

d. NOX Adsorber System MIL Illumination and DTC Storage
    We are proposing the general requirements for MIL illumination and 
DTC storage discussed in section II.A.2.
8. Diesel Particulate Filter (DPF) System Monitoring
a. Background
    Diesel particulate filters control diesel PM by capturing the soot 
(solid carbon) portion of PM in a filter media, typically a ceramic 
wall flow substrate, and then by oxidizing (burning) it in the oxygen-
rich atmosphere of diesel exhaust.\28\ In aggregate over a driving 
cycle, the PM must be burned at a rate equal to or

[[Page 3221]]

greater than its accumulation rate, or the DPF will clog. Given low 
sulfur diesel fuel (diesel fuel with a sulfur content of 15 ppm or 
lower), highly active catalytic metals (e.g., platinum) can be used to 
promote soot oxidation. This method of PM filter regeneration, called 
passive regeneration, is the primary means of soot oxidation that we 
project industry will use in 2007/2010.
---------------------------------------------------------------------------

    \28\ See ``Regulatory Impact Analysis: Heavy-Duty Engine and 
Vehicle Standards and Highway Diesel Fuel Sulfur Control 
Requirements;'' EPA420-R-00-026; December 2000 at Chapter III for a 
more complete description of DPFs.
---------------------------------------------------------------------------

    The DPF technology has proven itself in tens of thousands of 
retrofit applications where low sulfur diesel fuel is already 
available. More than a million light-duty passenger cars in Europe now 
have diesel particulate filters. DPFs are considered the most effective 
control technology for the reduction of particulate emissions and can 
typically achieve PM reductions in excess of 90 percent.
    In order to maintain the performance of the DPF and the engine, the 
trapped PM must be periodically removed before too much particulate is 
accumulated and exhaust backpressure reaches unacceptable levels. The 
process of periodically removing accumulated PM from the DPF is known 
as ``regeneration'' and is very important for maintaining low PM 
emission levels. DPF regeneration can be passive (i.e., occur 
continuously during regular operation of the filter), active (i.e., 
occur on a controlled, periodic basis after a predetermined quantity of 
particulates have been accumulated), or a combination of the two. With 
passive regeneration, the oxidizing catalyst material on the DPF 
substrate serves to lower the temperature for oxidizing PM. This allows 
the DPF to continuously oxidize trapped PM material during normal 
driving. In contrast, active systems utilize an external heat source--
such as an electric heater or fuel burner--to facilitate DPF 
regeneration. We are projecting that virtually all DPF systems will 
have some sort of active regeneration mechanism as a backup mechanism 
should operating conditions not be conducive for passive regeneration.
    One of the key considerations for a DPF regeneration control system 
is the amount of soot quantity that is stored in the DPF (often called 
soot loading). If too much soot is stored when regeneration is 
activated, the soot can burn uncontrollably and DPF substrate could be 
damaged via melting or cracking. Conversely, activating regeneration 
when there is too little trapped soot will not ensure good combustion 
propagation which would effectively waste the energy (fuel) used to 
initiate the regeneration. Another important consideration in the 
control system design is the fuel economy penalty involved with DPF 
regeneration. Prolonged operation with high backpressures in the 
exhaust and regenerations occurring too frequently are both detrimental 
to fuel economy and DPF durability. Therefore, DPF system designers 
will need to carefully balance the regeneration frequency with various 
conflicting factors. To optimize the trap regeneration for these design 
factors, the DPF regeneration control system is projected to 
incorporate both pressure sensors and temperature sensors to model soot 
loading and other phenomena.\29\ Through the information provided by 
these sensors, designers can optimize the DPF for high effectiveness 
and maximum durability while minimizing fuel economy and performance 
penalties.
---------------------------------------------------------------------------

    \29\ Salvat, O., Marez, P., and Belot, G., ``Passenger Car 
Serial Application of a Particulate Filter System on a Common Rail 
Direct Injection Diesel Engine,'' SAE Paper 2000-01-0473 which may 
be obtained from Society of Automotive Engineers International, 400 
Commonwealth Dr., Warrendale, PA, 15096-0001.
---------------------------------------------------------------------------

b. DPF System Monitoring Requirements
    We are proposing that the OBD system monitor the DPF on engines so-
equipped for proper performance.\30\ For engines equipped with active 
regeneration systems that utilize an active/intrusive injection (e.g., 
in-exhaust fuel injection, in-exhaust fuel/air burner), the OBD system 
would have to monitor the active/intrusive injection system for proper 
performance. The individual electronic components (e.g., injectors, 
valves, sensors) that are used in the active/intrusive injection system 
must be monitored in accordance with the comprehensive component 
requirements in section II.D.4.
---------------------------------------------------------------------------

    \30\ Note that these requirements would also apply to a 
catalyzed diesel particulate filter (CDPF). We use the more common 
term DPF throughout this discussion.
---------------------------------------------------------------------------

i. PM Filtering Performance
    We are proposing that the OBD system detect a malfunction prior to 
a decrease in the filtering capability of the DPF (e.g., cracking, 
melting, etc.) that would cause an engine's PM emissions to exceed the 
applicable emissions thresholds for ``DPF Systems'' as shown in Table 
II.B-1. If no failure or deterioration of the PM filtering performance 
could result in an engine's PM emissions exceeding the applicable 
emissions thresholds, the OBD system would have to detect a malfunction 
when no detectable amount of PM filtering occurs.
ii. DPF Regeneration Frequency Malfunctions--Too Frequent
    We are proposing that the OBD system detect a malfunction when the 
DPF regeneration frequency increases from--i.e., occurs more often 
than--the manufacturer's specified regeneration frequency to a level 
such that it would cause an engine's NMHC emissions to exceed the 
applicable emissions threshold for ``DPF Systems'' as shown in Table 
II.B-1. If no such regeneration frequency exists that could cause NMHC 
emissions to exceed the applicable emission threshold, the OBD system 
would have to detect a malfunction when the PM filter regeneration 
frequency exceeds the manufacturer's specified design limits for 
allowable regeneration frequency.
iii. DPF Incomplete Regeneration Malfunctions
    We are proposing that the OBD system detect a regeneration 
malfunction when the DPF does not properly regenerate under 
manufacturer-defined conditions where regeneration is designed to 
occur.
iv. DPF NMHC Conversion Efficiency Malfunctions
    We are proposing that, for any DPF that serves to convert NMHC 
emissions, the OBD system must monitor the NMHC converting function of 
the DPF and detect a malfunction when the NMHC conversion capability 
decreases to the point that NMHC emissions exceed the NMHC threshold 
for ``DPF Systems'' as shown in Table II.B-1. If no failure or 
deterioration of the NMHC conversion capability could result in NMHC 
emissions exceeding the applicable NMHC threshold, the OBD system would 
have to detect a malfunction when the system has no detectable amount 
of NMHC conversion capability.
v. DPF Missing Substrate Malfunctions
    We are proposing that the OBD system detect a malfunction if either 
the DPF substrate is completely destroyed, removed, or missing, or if 
the DPF assembly has been replaced with a muffler or straight pipe.
vi. DPF Active/Intrusive Injection System Malfunctions
    We are proposing that, for systems that utilize active/intrusive 
injection (e.g., in-cylinder post fuel injection, in-exhaust air-
assisted fuel injection) to achieve DPF regeneration, the OBD system 
detect a malfunction if any

[[Page 3222]]

failure or deterioration of the injection system's ability to properly 
regulate injection causes the system to be unable to achieve DPF 
regeneration.
vii. DPF Regeneration Feedback Control System Malfunctions
    We are proposing that, if the engine is equipped with feedback 
control of the DPF regeneration (e.g., feedback control of oxidation 
catalyst inlet temperature, PM filter inlet or outlet temperature, in-
cylinder or in-exhaust fuel injection), the OBD system must detect a 
malfunction when and if:
     The system fails to begin feedback control within a 
manufacturer specified time interval;
     A failure or deterioration causes open loop or default 
operation; or
     Feedback control has used up all of the adjustment allowed 
by the manufacturer.
c. DPF System Monitoring Conditions
    We are proposing that manufacturers define the monitoring 
conditions for all DPF related malfunctions such that the minimum 
performance ratio requirements discussed in section II.E would be met 
with the exception that monitoring must occur every time the monitoring 
conditions are met during the driving cycle rather than once per 
driving cycle as required for most monitors. For purposes of tracking 
and reporting as required in section II.E, all monitors used to detect 
all DPF related malfunctions would have to be tracked separately but 
reported as a single set of values as specified in section II.E.\31\
---------------------------------------------------------------------------

    \31\ For specific components or systems that have multiple 
monitors that are required to be reported (e.g., exhaust gas sensor 
bank 1 may have multiple monitors for sensor response or other 
sensor characteristics), the OBD system must separately track 
numerators and denominators for each of the specific monitors and 
report only the corresponding numerator and denominator for the 
specific monitor that has the lowest numerical ratio. If two or more 
specific monitors have identical ratios, the corresponding numerator 
and denominator for the specific monitor that has the highest 
denominator shall be reported for the specific component.
---------------------------------------------------------------------------

d. DPF System MIL Illumination and DTC Storage
    We are proposing the general requirements for MIL illumination and 
DTC storage as discussed in section II.A.2.
9. Exhaust Gas Sensor Monitoring
a. Background
    Exhaust gas sensors (e.g., oxygen sensors, wide-range air-fuel (A/
F) sensors, NOX sensors) are important to the emission 
control system of vehicles. These sensors are used for enhancing the 
performance of several emission control technologies (e.g., catalysts, 
EGR systems). We expect that both oxygen sensors and wide range A/F 
sensors may be used by heavy-duty manufacturers to optimize their 
emission control technologies. We would expect that, in addition to 
their emissions control functions, these sensors will also be used to 
satisfy many of the proposed HDOBD monitoring requirements, such as 
fuel system monitoring, catalyst monitoring, and EGR system monitoring. 
NOX sensors may also be used for optimization of several 
diesel emission control technologies, such as NOX adsorbers 
and selective catalytic reduction (SCR) systems. Since an exhaust gas 
sensor can be a critical component of a vehicle's fuel and emission 
control system, the proper performance of this component needs to be 
assured to maintain low emissions. The reliance on these sensors for 
emissions control and OBD monitoring makes it important that any 
malfunction that adversely affects the performance of any of these 
sensors be detected by the OBD system.
b. Exhaust Gas Sensor Monitoring Requirements
    We are proposing that the OBD system monitor all exhaust gas 
sensors (e.g., oxygen, air-fuel ratio, NOX) used either for 
emission control system feedback (e.g., EGR control/feedback, SCR 
control/feedback, NOX adsorber control/feedback), or as a 
monitoring device, for proper output signal, activity, response rate, 
and any other parameter that can affect emissions. For engines equipped 
with heated exhaust gas sensors, the OBD system would have to monitor 
the heater for proper performance.
i. Air/Fuel Ratio Sensor Malfunctions
    For all air/fuel ratio sensors, we are proposing the following:
     Circuit malfunctions: The OBD system must detect 
malfunctions of the sensor caused by either a lack of circuit 
continuity or out-of-range values.
     Feedback malfunctions: The OBD system must detect a 
malfunction of the sensor when a sensor failure or deterioration causes 
an emissions control system--e.g., the EGR, SCR, or NOX 
adsorber systems--to stop using that sensor as a feedback input (e.g., 
causes default or open-loop operation).
     Monitoring capability: To the extent feasible, the OBD 
system must detect a malfunction of the sensor when the sensor output 
voltage, resistance, impedance, current, amplitude, activity, offset, 
or other characteristics are no longer sufficient for use as an OBD 
system monitoring device (e.g., for catalyst, EGR, SCR, or 
NOX adsorber monitoring).
    Specifically for sensors located upstream of an aftertreatment 
device, we are proposing the following:
     Sensor performance malfunctions: The OBD system must 
detect a malfunction prior to any failure or deterioration of the 
sensor voltage, resistance, impedance, current, response rate, 
amplitude, offset, or other characteristic(s) that would cause an 
engine's emissions to exceed the applicable emissions thresholds for 
``Other Monitors'' as shown in Table II.B-1.
    Specifically for sensors located downstream of an aftertreatment 
device, we are proposing the following:
     Sensor performance malfunctions: The OBD system must 
detect a malfunction prior to any failure or deterioration of the 
sensor voltage, resistance, impedance, current, response rate, 
amplitude, offset, or other characteristic(s) that would cause an 
engine's emissions to exceed the applicable emissions thresholds for 
``Air-fuel ratio sensors downstream of aftertreatment devices'' as 
shown in Table II.B-1.
ii. NOX Sensor Malfunctions
    For NOX sensors, we are proposing the following:
     Sensor performance malfunctions: The OBD system must 
detect a malfunction prior to any failure or deterioration of the 
sensor voltage, resistance, impedance, current, response rate, 
amplitude, offset, or other characteristic(s) that would cause an 
engine's emissions to exceed the applicable emissions thresholds for 
``NOX sensors'' as shown in Table II.B-1.
     Circuit malfunctions: The OBD system must detect 
malfunctions of the sensor caused by either a lack of circuit 
continuity or out-of-range values.
     Feedback malfunctions: The OBD system shall detect a 
malfunction of the sensor when a sensor failure or deterioration causes 
an emission control--e.g., the EGR, SCR, or NOX adsorber 
systems--to stop using that sensor as a feedback input (e.g., causes 
default or open-loop operation).
     Monitoring capability: To the extent feasible, the OBD 
system must detect a malfunction of the sensor when the sensor output 
voltage, resistance, impedance, current, amplitude, activity, offset, 
or other characteristics are no longer sufficient for use as an OBD 
system monitoring device (e.g., for catalyst, EGR, SCR, or 
NOX adsorber monitoring).

[[Page 3223]]

iii. Other Exhaust Gas Sensor Malfunctions
    For other exhaust gas sensors, we are proposing that the 
manufacturer submit a monitoring plan to the Administrator for 
approval. The Administrator would approve the request upon determining 
that the manufacturer has submitted data and an engineering evaluation 
that demonstrate that the monitoring plan is as reliable and effective 
as the monitoring plan required for air/fuel ratio sensors and 
NOX sensors.
iv. Exhaust Gas Sensor Heater Malfunctions
    We are proposing that the OBD system detect a malfunction of the 
heater performance when the current or voltage drop in the heater 
circuit is no longer within the manufacturer's specified limits for 
normal operation (i.e., within the criteria required to be met by the 
component vendor for heater circuit performance at high mileage). The 
manufacturer may use other malfunction criteria for heater performance 
malfunctions. To do so, the manufacturer would be required to submit 
data and/or engineering analyses that demonstrate that the monitoring 
reliability and timeliness would be equivalent to the criteria stated 
here. Further, the OBD system would be required to detect malfunctions 
of the heater circuit including open or short circuits that conflict 
with the commanded state of the heater (e.g., shorted to 12 Volts when 
commanded to 0 Volts (ground)).
c. Exhaust Gas Sensor Monitoring Conditions
    For exhaust gas sensor performance malfunctions, we are proposing 
that manufacturers define the monitoring conditions such that the 
minimum performance ratio requirements discussed in section II.E would 
be met. For purposes of tracking and reporting as required in section 
II.E, all monitors used to detect sensor performance malfunctions would 
have to be tracked separately but reported as a single set of values as 
specified in section II.E.\32\
---------------------------------------------------------------------------

    \32\ For specific components or systems that have multiple 
monitors that are required to be reported (e.g., exhaust gas sensor 
bank 1 may have multiple monitors for sensor response or other 
sensor characteristics), the OBD system must separately track 
numerators and denominators for each of the specific monitors and 
report only the corresponding numerator and denominator for the 
specific monitor that has the lowest numerical ratio. If two or more 
specific monitors have identical ratios, the corresponding numerator 
and denominator for the specific monitor that has the highest 
denominator shall be reported for the specific component.
---------------------------------------------------------------------------

    For exhaust gas sensor monitoring capability malfunctions, 
manufacturers would have to define the monitoring conditions such that 
the minimum performance ratio requirements discussed in section II.E 
would be met with the exception that monitoring must occur every time 
the monitoring conditions are met during the driving cycle rather than 
once per driving cycle as required for most monitors.
    For exhaust gas sensor circuit malfunctions and feedback 
malfunctions, monitoring must be conducted continuously.
    The manufacturer may disable continuous exhaust gas sensor 
monitoring when an exhaust gas sensor malfunction cannot be 
distinguished from other effects (e.g., disable ``out-of-range low'' 
monitoring during fuel cut conditions). To do so, the manufacturer 
would be required to submit test data and/or engineering analyses that 
demonstrate that a properly functioning sensor cannot be distinguished 
from a malfunctioning sensor and that the disablement interval is 
limited only to that necessary for avoiding a false detection.
    For exhaust gas sensor heater malfunctions, manufacturers must 
define monitoring conditions such that the minimum performance ratio 
requirements discussed in section II.E would be met. Monitoring for 
sensor heater circuit malfunctions must be conducted continuously.
d. Exhaust Gas Sensor MIL Illumination and DTC Storage
    We are proposing the general requirements for MIL illumination and 
DTC storage as discussed in section II.A.2.

C. Monitoring Requirements and Timelines for Gasoline/Spark-Ignition 
Engines

    Table II.C-1 summarizes the proposed gasoline fueled spark ignition 
emissions thresholds at which point a component or system has failed to 
the point of requiring an illuminated MIL and a stored DTC. Table II.C-
2 summarizes the proposed implementation schedule for these 
thresholds--i.e., the proposed certification requirements and in-use 
liabilities. More detail regarding the specific monitoring 
requirements, implementation schedules, and liabilities can be found in 
the sections that follow.

         Table II.C-1.--Proposed Emissions Thresholds for Gasoline Fueled SI Engines Over 14,000 Pounds
----------------------------------------------------------------------------------------------------------------
        Component/Monitor                  MY                 NMHC                 CO                 NOX
----------------------------------------------------------------------------------------------------------------
Catalytic converter system.......  2010+.............  1.75x.............  ..................  1.75x
``Other monitors'' with emissions  2010+.............  1.5x..............  1.5x..............  1.5x
 thresholds (see section II.C).
Evaporative emissions control      2010+.............  0.150 inch leak ..
 system.
----------------------------------------------------------------------------------------------------------------
Notes: MY=Model Year; 1.75x means a multiple of 1.75 times the applicable emissions standard; not all proposed
  monitors have emissions thresholds but instead rely on functionality and rationality checks as described in
  section II.D.4. The evaporative emissions control system threshold is not, technically, an emissions threshold
  but rather a leak size that must be detected; nonetheless, for ease we refer to this as the threshold.

    There are exceptions to the emissions thresholds shown in Table 
II.C-1 whereby a manufacturer can demonstrate that emissions do not 
exceed the threshold even when the component or system is non-
functional at which point a functional check would be allowed.
    The monitoring requirements described below for gasoline engines 
mirror those that are already in place for gasoline engines used in 
vehicles under 14,000 pounds. The HD gasoline industry--General Motors 
and Ford, as of today \33\--have told us that their preference is to 
use essentially the same OBD system on their engines used in both under 
and over 14,000 pound vehicles.\34\ In general, we agree with the

[[Page 3224]]

HD gasoline industry on this issue for three reasons:
---------------------------------------------------------------------------

    \33\ This is true according to our certification database for 
both he 2004 and 2005 model years. Other manufacturers certify 
engines that use the Otto cycle, but those engines do not burn 
gasoline and instead burn various alternative fuels.
    \34\ ``EMA Comments on Proposed HDOBD Requirements for HDGE,'' 
bullet items 3 and 4; April 28, 2005, Docket ID EPA-HQ-OAR-
2005-0047-0003.
---------------------------------------------------------------------------

     The engines used in vehicles above and below 14,000 pounds 
are the same which makes it easy for industry to use the same OBD 
monitors.
     The existing OBD requirements for engines used in vehicles 
below 14,000 pounds have proven effective; and,
     The industry members have more than 10 years experience 
complying with the OBD requirements for engines used in vehicles below 
14,000 pounds.
    As a result, we are proposing requirements that should allow for 
OBD system consistency in vehicles under and over 14,000 pounds rather 
than proposing requirements that mirror the proposed HD diesel 
requirements discussed in section II.B. Nonetheless, the requirements 
proposed below are for engine-based OBD monitors only rather than 
monitors for the entire powertrain (which would include the 
transmission). We are doing this for the same reasons as done for the 
proposed diesel OBD requirements in that certification of gasoline 
applications over 14,000 pounds, like their diesel counterparts, is 
done on an engine basis and not a vehicle basis.
1. Fuel System Monitoring
a. Background
    As with diesel engines, the fuel system of a gasoline engine is an 
essential component of the engine's emissions control system. Proper 
delivery of fuel is essential to maintain stoichiometric operation and 
minimize engine out emissions. Proper stoichiometric control is also 
critical to maximize catalyst conversion efficiency and reach low 
tailpipe emission levels. As such, thorough monitoring of the fuel 
system is an essential element in an OBD system.
    For gasoline engines, the fuel system generally includes a fuel 
pump, fuel pressure regulator, fuel rail, individual injectors for each 
cylinder, and a closed-loop feedback control system using oxygen 
sensor(s) or air-fuel ratio (A/F) sensor(s). The feedback sensors are 
located in the exhaust system and are used to regulate the fuel 
injection quantity to achieve a stoichiometric mixture in the exhaust. 
If the sensor indicates a rich (or lean) mixture, the system reduces 
(or increases) the amount of fuel being injected by applying a short 
term correction to the fuel injection quantity calculated for the 
current engine operating condition. To account for aging or 
deterioration in the system such as reduced injector flow, more 
permanent long term corrections are also learned and applied to the 
fuel injection quantity for more precise fueling.
    For gasoline engines, fuel system monitoring has been implemented 
on light-duty vehicles since the 1996 model year and on heavy-duty 
vehicles less than 14,000 pounds and the engines used in those vehicles 
since the 2004/2005 model year. For heavy-duty gasoline engines used in 
vehicles over 14,000 pounds (many of which are the same engine as is 
used in vehicles less than 14,000 pounds), the system components and 
control strategies are identical to those used in the light-duty and 
under 14,000 pound categories. As such, the monitoring requirements 
established for engines used in vehicles less than 14,000 pounds can be 
directly applied to engines used in vehicles over 14,000 pounds.
b. Fuel System Monitoring Requirements
    We are proposing that the fuel system be continuously monitored for 
its ability to maintain engine emissions below the applicable emissions 
thresholds. Manufacturers would also be required to verify that the 
fuel system is in closed-loop operation--e.g., that it is using the 
oxygen sensor for feedback control. The individual components of the 
fuel system would also be covered by separate monitoring requirements 
for oxygen sensors, misfire (for the fuel injectors), and comprehensive 
components (in systems such as those with electronically-controlled 
variable speed fuel pumps or electronically-controlled fuel pressure 
regulators).
i. Fuel System Performance
    We are proposing that the OBD system be required to detect a 
malfunction of the fuel delivery system (including feedback control 
based on a secondary oxygen sensor) when the fuel delivery system is 
unable to maintain the engine's emissions at or below the applicable 
emissions thresholds for ``Other monitors'' as shown in Table II.C-1.
ii. Fuel System Feedback Control
    If the engine is equipped with adaptive feedback control, we are 
proposing that the OBD system be required to detect a malfunction when 
the adaptive feedback control has used up all of the adjustment allowed 
by the manufacturer. However, if the engine is equipped with feedback 
control that is based on a secondary oxygen (or equivalent) sensor, the 
OBD system would not be required to detect a malfunction of the fuel 
system solely when the feedback control based on that secondary oxygen 
sensor has used up all of the adjustment allowed by the manufacturer. 
For such systems, the OBD system would be required to meet the fuel 
system performance requirements presented above.
    Additionally, we are proposing that the OBD system be required to 
detect a malfunction whenever the fuel control system fails to enter 
closed loop operation within a time interval after engine startup. The 
manufacturer would be required to submit data and/or engineering 
analyses that support their chosen time interval.
    Lastly, manufacturers would be allowed to adjust the malfunction 
criteria and/or monitoring conditions to compensate for changes in 
altitude, temporary introduction of large amounts of purge vapor, or 
for other similar identifiable operating conditions when they occur.
c. Fuel System Monitoring Conditions
    We are proposing that the OBD system monitor continuously for 
malfunctions of the fuel system.
d. Fuel System MIL Illumination and DTC Storage
    We are proposing that a pending DTC be stored immediately upon 
detecting a malfunction according to the fuel system monitoring 
requirements presented in section II.C.1.b (i.e., rather than waiting 
until the end of the drive cycle to store the pending DTC). Once a 
pending DTC is stored, the OBD system would be required to illuminate 
the MIL immediately and store a MIL-on DTC if a malfunction is again 
detected during either of the following two events: (1) The drive cycle 
immediately following the drive cycle during which the pending DTC was 
stored, regardless of the conditions encountered during the drive 
cycle; or, (2) on the next drive cycle during which similar conditions 
are encountered to those that occurred when the pending DTC was 
stored.\35\
---------------------------------------------------------------------------

    \35\ ``Similar conditions,'' as used in conjunction with misfire 
and fuel system monitoring, means engine conditions having an engine 
speed within 375 rpm, load conditions within 20 percent, and the 
same warm up status (i.e., cold or hot) as existing during the 
applicable previous problem detection. The Administrator may approve 
other definitions of similar conditions based on comparable 
timeliness and reliability in detecting similar engine operation.
---------------------------------------------------------------------------

    We are also proposing that the pending DTC may be erased at the end 
of the next drive cycle in which similar conditions have been 
encountered without detecting a malfunction according to the fuel 
system monitoring requirements. The pending DTC may also be erased if 
similar conditions are not encountered during the 80 drive cycles 
immediately after the initial

[[Page 3225]]

detection of a malfunction for which the pending DTC was set.
    We are proposing some specific requirements with respect to storage 
of freeze frame information associated with fuel system malfunctions. 
First, the OBD system must store and erase freeze frame information 
either in conjunction with storing and erasing a pending DTC or in 
conjunction with storing and erasing a MIL-on DTC. Second, if freeze 
frame information is already stored for a malfunction other than an 
engine misfire or fuel system malfunction at the time that a fuel 
system DTC is stored, the preexisting freeze frame information must be 
replaced with freeze frame information regarding the fuel system 
malfunction.
    The OBD system would also be required to store the engine speed, 
load, and warm up status present when the first fuel system malfunction 
is detected that resulted in the storage of the pending DTC. The MIL 
may be extinguished after three sequential drive cycles in which 
similar conditions have been encountered without detecting a 
malfunction of the fuel system.
2. Engine Misfire Monitoring
a. Background
    Detecting engine misfire on a gasoline spark ignition engine is 
important for two reasons: Its impact on the emissions performance of 
the engine and its impact on the durability of the catalytic converter. 
Engine misfire has two primary causes: Lack of spark and poor fuel 
metering (delivery). When misfire occurs, unburned fuel and air are 
pumped out of the engine and into the exhaust system and into the 
catalyst. This can increase dramatically the operating temperature of 
the catalyst where temperatures can soar to above 900 degrees Celsius. 
This problem is usually most severe under high load/high speed engine 
operating conditions and can cause irreversible damage to the catalyst. 
Though the durability of catalysts has been improving, most are unable 
to sustain continuous operation at such high temperatures. Engine 
misfire also contributes to poor emissions performance, especially when 
the misfire occurs during engine warm-up and the catalyst itself has 
not yet reached its operating temperature.
b. Engine Misfire Monitoring Requirements
    We are proposing that the OBD system detect both engine misfire 
capable of causing catalyst damage and engine misfire capable of 
causing poor emissions performance. Additionally, the OBD system would 
be required to identify the specific cylinder in which misfire is 
occurring and/or if there exists a condition in which more than one 
cylinder is misfiring; when identifying a multiple cylinder misfire 
condition, the OBD system would not be required to identify 
individually each of the misfiring cylinders. We are proposing an 
exception to this whereby if more than 90 percent of the detected 
misfires are occurring in a single cylinder, the manufacturer may elect 
to consider it a single cylinder misfire condition rather than a 
multiple cylinder misfire condition. However, we are proposing that, if 
two or more cylinders individually have more than 10 percent of the 
total number of detected misfires, the manufacturer must consider it a 
multiple cylinder misfire condition.
i. Engine Misfire Capable of Causing Catalyst Damage
    We are proposing that the manufacturer be required to detect the 
percentage of misfire--evaluated in 200 revolution increments--for each 
engine speed and load condition that would result in a temperature 
capable of damaging the catalyst. For every engine speed and load 
condition at which this percentage is determined to be less than five 
percent, the manufacturer may set the malfunction criteria at five 
percent. The manufacturer may use a longer interval than a 200 
revolution increment but only for determining, on a given drive cycle, 
the first misfire exceedance; upon detecting the first such exceedance, 
the 200 revolution increment must be used. The manufacturer may use a 
longer initial interval by submitting data and/or engineering analyses 
that demonstrate that catalyst damage would not occur due to 
unacceptably high catalyst temperatures before the interval has 
elapsed.
    Further, we are proposing that, for the purpose of establishing the 
temperature at which catalyst damage would occur, manufacturers not be 
allowed to define the catalyst damaging temperature at a temperature 
more severe than what the catalyst system could be operated at for 10 
consecutive hours and still meet the applicable standards.
ii. Engine Misfire Causing Poor Emissions Performance
    We are proposing that the manufacturer be required to detect the 
percentage of misfire--evaluated in 1000 revolution increments--that 
would cause emissions to exceed the emissions thresholds for ``Other 
monitors'' as shown in Table II.C-1 if that percentage of misfire were 
present from the beginning of the test procedure. To establish this 
percentage of misfire, the manufacturer would be required to use 
misfire events occurring at equally spaced, complete engine cycle 
intervals, across randomly selected cylinders throughout each 1000 
revolution increment. If this percentage of misfire is determined to be 
lower than one percent, the manufacturer may set the malfunction 
criteria at one percent. The manufacturer may use a different interval 
than a 1000 revolution increment. To do so, the manufacturer would be 
required to submit data and/or engineering analyses demonstrating that 
the strategy would be equally effective and timely at detecting 
misfire. A malfunction must be detected if the percentage of misfire is 
exceeded regardless of the pattern of misfire events (e.g., random, 
equally spaced, continuous).
c. Engine Misfire Monitoring Conditions
    We are proposing that the OBD system monitor continuously to detect 
engine misfire under all of the following conditions:
     From no later than the end of the second crankshaft 
revolution after engine start;
     During the rise time and settling time as the engine 
reaches the desired idle speed immediately following engine start-up 
(i.e., ``flare-up'' and ``flare-down''); and,
     Under all positive torque conditions except within the 
engine operating region bound by lines connecting the following three 
points: An engine speed of 3000 rpm with the engine load at the 
positive torque line (i.e., engine load with the transmission in 
neutral), an engine speed at the redline rpm with the engine load at 
the positive torque line, and an engine speed at the redline rpm with 
an engine load at which intake manifold vacuum is four inches of 
mercury lower than that at the positive torque line (this would be an 
engine load somewhat greater than the engine load at the positive 
torque line).\36\
---------------------------------------------------------------------------

    \36\ ``Redline engine speed'' is actually defined by the 
manufacturer as either the recommended maximum engine speed as 
normally displayed on instrument panel tachometers or the engine 
speed at which fuel shutoff occurs.
---------------------------------------------------------------------------

    If a monitoring system cannot detect all misfire patterns under the 
required engine speed and load conditions, the manufacturer may request 
approval of the system nonetheless. In evaluating the manufacturer's 
request, the Administrator would consider:
     The magnitude of the region(s) in which misfire detection 
is limited;
     The degree to which misfire detection is limited in those 
region(s)

[[Page 3226]]

(i.e., the probability of detection of misfire events);
     The frequency with which said region(s) are expected to be 
encountered in-use;
     The type of misfire patterns for which misfire detection 
is troublesome; and,
     Demonstration that the monitoring technology being used is 
not inherently incapable of detecting misfire under the required 
conditions (i.e., compliance can be achieved by other manufacturers on 
their engines).
    The Administrator's evaluation would be based on the following 
misfire patterns:
     Equally spaced misfire occurring on randomly selected 
cylinders;
     Single cylinder continuous misfire; and,
     Paired cylinder (cylinders firing at the same crank angle) 
continuous misfire.
    Further, a manufacturer may use a monitoring system that has 
reduced misfire detection capability during the portion of the first 
1000 revolutions after engine start during which a cold start emission 
reduction strategy is active that reduces engine torque (e.g., spark 
retard strategies). To do so, the manufacturer would be required to 
submit data and/or engineering analyses demonstrating that the 
probability of detection is greater than or equal to 75 percent during 
the worst case condition (i.e., lowest generated torque) for a vehicle 
operated continuously at idle (park/neutral idle) on a cold start 
between 50 and 86 degrees Fahrenheit and that the technology cannot 
reliably detect a higher percentage of the misfire events during these 
conditions.
    A manufacturer may disable misfire monitoring or use an alternative 
malfunction criterion when misfire cannot be distinguished from other 
effects. To do so, the manufacturer would be required to submit data 
and/or engineering analyses demonstrating that the disablement interval 
or period of use of an alternative malfunction criterion is limited 
only to that necessary for avoiding a false detection (errors of 
commission). Such disablements would be allowed for conditions 
involving:
     Rough road;
     Fuel cut;
     Gear changes for manual transmission vehicles;
     Traction control or other vehicle stability control 
activation such as anti-lock braking or other engine torque 
modifications to enhance vehicle stability;
     Off-board control or intrusive activation of vehicle 
components or diagnostics during service or assembly plant testing;
     Portions of intrusive evaporative system or EGR 
diagnostics that can significantly affect engine stability (i.e., while 
the purge valve is open during the vacuum pull-down of a evaporative 
system leak check but not while the purge valve is closed and the 
evaporative system is sealed or while an EGR diagnostic causes the EGR 
valve to be intrusively cycled on and off during positive torque 
conditions); or,
     Engine speed, load, or torque transients due to throttle 
movements more rapid than occurs over the FTP cycle for the worst case 
engine within each engine family.
    Additionally, the manufacturer may disable misfire monitoring when 
the fuel level is 15 percent or less of the nominal capacity of the 
fuel tank, when PTO units are active, or while engine coolant 
temperature is below 20 degrees Fahrenheit. For the latter case, the 
manufacturer may continue the misfire monitoring disablement until 
engine coolant temperature exceeds 70 degrees Fahrenheit provided the 
manufacturer can demonstrate that it is necessary.
    In general, the Administrator would not approve misfire monitoring 
disablement for conditions involving normal air conditioning compressor 
cycling from on-to-off or off-to-on, automatic transmission gear shifts 
(except for shifts occurring during wide open throttle operation), 
transitions from idle to off-idle, normal engine speed or load changes 
that occur during the engine speed rise time and settling time (i.e., 
``flare-up'' and ``flare-down'') immediately after engine starting 
without any vehicle operator-induced actions (e.g., throttle stabs), or 
excess acceleration (except for acceleration rates that exceed the 
maximum acceleration rate obtainable at wide open throttle while the 
vehicle is in gear due to abnormal conditions such as slipping of a 
clutch).
    Further, the manufacturer may request approval of other misfire 
monitoring disablements or use of alternative malfunction criteria for 
any other condition. The Administrator would consider such requests on 
a case by case basis and will consider whether or not the manufacturer 
has demonstrated that the request is based on an unusual or unforeseen 
circumstance and that it is applying the best available computer and 
monitoring technology.
    For engines with more than eight cylinders that cannot meet the 
continuous monitoring and detection requirements listed above, a 
manufacturer may use alternative misfire monitoring conditions. Any 
manufacturer wishing to use alternative misfire monitoring conditions 
must submit data and/or an engineering evaluation that demonstrate that 
misfire detection throughout the required operating region cannot be 
achieved when using proven monitoring technology (i.e., a technology 
that provides for compliance with these requirements on other engines) 
and provided misfire is detected to the fullest extent permitted by the 
technology. However, the misfire detection system would still be 
required to monitor during all positive torque operating conditions 
encountered during an FTP transient cycle.
d. Engine Misfire MIL Illumination and DTC Storage
    Manufacturers may store a general misfire DTC instead of a cylinder 
specific DTC under certain operating conditions. Do so shall depend on 
the manufacturer submitting data and/or an engineering evaluation that 
demonstrate that the specific misfiring cylinder cannot be reliably 
identified when the certain operating conditions occur.
i. Engine Misfire Capable of Causing Catalyst Damage
    We are proposing that a pending DTC shall be stored immediately if, 
during a single drive cycle, the percentage of misfire determined by 
the manufacturer as being capable of causing catalyst damage is 
exceeded three times when operating in the positive torque region 
encountered during an FTP transient cycle or is exceeded on a single 
occasion when operating at any other engine speed and load condition in 
the positive torque region defined above. Immediately after a pending 
DTC is stored, the MIL shall blink once per second at all times while 
misfire is occurring during the drive cycle (i.e., the MIL may be 
extinguished during those times when misfire is not occurring during 
the drive cycle). If, at the time such a catalyst damaging engine 
misfire is occurring, the MIL is already illuminated for a malfunction 
other than engine misfire, the MIL shall blink similarly while the 
engine misfire is occurring and, if the misfire ceases, the MIL shall 
stop blinking but shall remain illuminated as commanded by the other 
malfunction.
    If a pending DTC is stored as described above, the OBD system shall 
immediately store a MIL-on DTC if the percentage of misfire determined 
by the manufacturer as being capable of causing catalyst damage is 
again exceeded one or more times during either: (a) the drive cycle 
immediately

[[Page 3227]]

following the storage of the pending DTC, regardless of the conditions 
encountered during the drive cycle; or, (b) on the next drive cycle in 
which similar conditions are encountered to those that existed when the 
pending DTC was stored.
    If, during a previous drive cycle, a pending DTC has been stored 
associated with detection of an engine misfire capable of causing poor 
emissions performance, the OBD system shall immediately store a MIL-on 
DTC if the percentage of misfire determined by the manufacturer as 
capable of causing catalyst damage is exceeded, regardless of the 
conditions encountered.
    Upon storage of a MIL-on DTC associated with engine misfire capable 
of causing catalyst damage, the MIL shall blink as described above 
while the engine misfire is occurring and then shall remain 
continuously illuminated if the engine misfire ceases. This MIL 
illumination logic shall continue until the requirements for 
extinguishing the MIL are met, as described below.
    If the engine misfire is not again detected by the end of the next 
drive cycle in which similar conditions are encountered to those that 
existed when the pending DTC was stored then the pending DTC shall be 
erased. The pending DTC may also be erased if similar conditions are 
not encountered during the 80 drive cycles subsequent to the initial 
malfunction detection.
    We are also proposing that engines with fuel shutoff and default 
fuel control--that are used to prevent catalyst damage should engine 
misfire capable of causing catalyst damage be detected--shall have some 
exemptions from these MIL illumination requirements. Most notably, the 
MIL is not required to blink while the catalyst damaging misfire is 
occurring. Instead, the MIL may simply illuminate in a steady fashion 
while the misfire is occurring provided that the fuel shutoff and 
default fuel control are activated as soon as the misfire is detected. 
Fuel shutoff and default fuel control may be deactivated only to permit 
fueling outside of the misfire range. Manufacturers may also 
periodically, but not more than once every 30 seconds, deactivate fuel 
shutoff and default fuel control to determine if the catalyst damaging 
misfire is still occurring. Normal fueling and fuel control may be 
resumed if the catalyst damaging misfire is no longer being detected.
    Manufacturers may also use a MIL illumination strategy that 
continuously illuminates the MIL in lieu of blinking the MIL during 
extreme misfire conditions capable of causing catalyst damage (i.e., 
misfire capable of causing catalyst damage that is occurring at all 
engine speeds and loads). Manufacturers would be allowed to use such a 
strategy only when catalyst damaging misfire levels cannot be avoided 
during reasonable driving conditions and the manufacturer can 
demonstrate that the strategy will encourage operation of the vehicle 
in conditions that will minimize catalyst damage (e.g., at low engine 
speeds and loads).
ii. Engine Misfire Causing Poor Emissions Performance
    We are proposing that, for a misfire detected within the first 1000 
revolutions after engine start during which misfire detection is 
active, a pending DTC shall be stored after the first exceedance of the 
percentage of misfire determined by the manufacturer as capable of 
causing poor emissions performance. If a pending DTC is stored, the OBD 
system shall illuminate the MIL and store a MIL-on DTC within 10 
seconds if an exceedance of the percentage of misfire is again detected 
in the first 1000 revolutions during any subsequent drive cycle, 
regardless of the conditions encountered during the driving cycle. The 
pending DTC shall be erased at the end of the next drive cycle in which 
similar conditions are encountered to those that existed when the 
pending DTC was stored provided the specified percentage of misfire is 
not again detected. The pending DTC may also be erased if similar 
conditions are not encountered during the 80 drive cycles subsequent to 
the initial malfunction detection.
    For a misfire detected after the first 1000 revolutions following 
engine start, a pending DTC shall be stored no later than after the 
fourth exceedance--during a single drive cycle--of the percentage of 
misfire determined by the manufacturer as being capable of causing poor 
emissions performance. If a pending DTC is stored, the OBD system shall 
illuminate the MIL and store a MIL-on DTC within 10 seconds if an 
exceedance of the percentage of misfire is again detected four times 
during: (a) the drive cycle immediately following the storage of the 
pending DTC, regardless of the conditions encountered during the drive 
cycle; or, (b) on the next drive cycle in which similar conditions are 
encountered to those that existed when the pending DTC was stored. The 
pending DTC shall be erased at the end of the next drive cycle in which 
similar conditions are encountered to those that existed when the 
pending DTC was stored provided the specified percentage of misfire is 
not again detected. The pending DTC may also be erased if similar 
conditions are not encountered during the 80 drive cycles subsequent to 
the initial malfunction detection.
    We are proposing some specific items with respect to freeze frame 
storage associated with engine misfire. The OBD system shall store and 
erase freeze frame conditions either in conjunction with storing and 
erasing a pending DTC or in conjunction with storing a MIL-on DTC and 
erasing a MIL-on DTC. In addition to those proposed requirements 
discussed in section II.A.2, we are proposing that, if freeze frame 
conditions are stored for a malfunction other than a misfire 
malfunction when a DTC is stored, the previously stored freeze frame 
information shall be replaced with freeze frame information regarding 
the misfire malfunction (i.e., the misfire's freeze frame information 
should take precedence over freeze frames for other malfunctions). 
Further, we are proposing that, upon detection of misfire, the OBD 
system store the following engine conditions: engine speed, load, and 
warm up status of the first misfire event that resulted in the storage 
of the pending DTC.
    Lastly, we are proposing that the MIL may be extinguished after 
three sequential driving cycles in which similar conditions have been 
encountered without an exceedance of the specified percentage of 
misfire.
3. Exhaust Gas Recirculation (EGR) Monitoring
a. Background
    EGR works to reduce NOX emissions the same way in 
gasoline engines as described earlier for diesel engines. First, the 
recirculated exhaust gases dilute the intake air--i.e., oxygen in the 
fresh air is displaced with relatively non-reactive exhaust gases--
which, in turn, results in less oxygen to form NOX. Second, 
EGR absorbs heat from the combustion process which reduces combustion 
chamber temperatures which, in turn, reduces NOX formation. 
The amount of heat absorbed from the combustion process is a function 
of EGR flow rate and recirculated gas temperature, both of which are 
controlled to minimize NOX emissions. EGR systems can 
involve many components to ensure accurate control of EGR flow, 
including valves, valve position sensors, and actuators.
b. EGR System Monitoring Requirements
    We are proposing that the OBD system monitor the EGR system on 
engines so equipped for low and high

[[Page 3228]]

flow rate malfunctions. The individual electronic components (e.g., 
actuators, valves, sensors) that are used in the EGR system must be 
monitored in accordance with the comprehensive component requirements 
in section II.D.4.
i. EGR Low Flow Malfunctions
    We are proposing that the OBD system detect a malfunction prior to 
a decrease from the manufacturer's specified EGR flow rate that would 
cause an engine's emissions to exceed the emissions thresholds for 
``other monitors'' as shown in Table II.C-1. For engines in which no 
failure or deterioration of the EGR system that causes a decrease in 
flow could result in an engine's emissions exceeding the applicable 
emissions thresholds, the OBD system would have to detect a malfunction 
when the system has reached its control limits such that it cannot 
increase EGR flow to achieve the commanded flow rate.
ii. EGR High Flow Malfunctions
    We are proposing that the OBD system detect a malfunction of the 
EGR system, including a leaking EGR valve--i.e., exhaust gas flowing 
through the valve when the valve is commanded closed--prior to an 
increase from the manufacturer's specified EGR flow rate that would 
cause an engine's emissions to exceed the emissions thresholds for 
``other monitors'' as shown in Table II.C-1. For engines in which no 
failure or deterioration of the EGR system that causes an increase in 
flow could result in an engine's emissions exceeding the applicable 
emissions thresholds, the OBD system would have to detect a malfunction 
when the system has reached its control limits such that it cannot 
reduce EGR flow to achieve the commanded flow rate.
c. EGR System Monitoring Conditions
    We are proposing that manufacturers define the monitoring 
conditions for EGR system malfunctions such that the minimum 
performance ratio requirements discussed in section II.E would be met. 
For purposes of tracking and reporting as required in section II.E, all 
monitors used to detect EGR low flow and high flow malfunctions must be 
tracked separately but reported as a single set of values as specified 
in section II.E.\37\
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    \37\ For specific components or systems that have multiple 
monitors that are required to be reported (e.g., exhaust gas sensor 
bank 1 may have multiple monitors for sensor response or other 
sensor characteristics), the OBD system must separately track 
numerators and denominators for each of the specific monitors and 
report only the corresponding numerator and denominator for the 
specific monitor that has the lowest numerical ratio. If two or more 
specific monitors have identical ratios, the corresponding numerator 
and denominator for the specific monitor that has the highest 
denominator shall be reported for the specific component.
---------------------------------------------------------------------------

    Manufacturers may temporarily disable the EGR system monitor under 
conditions when monitoring may not be reliable (e.g., when freezing may 
affect performance of the system). Such temporary disablement would be 
allowed provided the manufacturer has submitted data and/or an 
engineering evaluation that demonstrate that the EGR monitor cannot be 
done reliably when these specific conditions exist.
d. EGR System MIL Illumination and DTC Storage
    We are proposing the general requirements for MIL illumination and 
DTC storage as discussed in section II.A.2.
4. Cold Start Emission Reduction Strategy Monitoring
a. Background
    The largest portion of exhaust emissions from gasoline engines is 
generated during the brief period following startup before the engine 
and catalyst have warmed up to their normal operating temperatures. To 
meet increasingly stringent emissions standards, manufacturers are 
developing hardware and associated control strategies to reduce these 
``cold start'' emissions. Most efforts center on reducing catalyst 
warm-up time.
    A cold catalyst is heated mainly by two mechanisms: heat 
transferred from the exhaust gases to the catalyst; and, heat generated 
in the catalyst as a result of the exothermic catalytic reactions. Most 
manufacturers use substantial spark retard and/or increased idle speed 
following a cold engine start, both of which maximize the heat 
available in the exhaust gases which, in turn, increases the heat 
transfer to the catalyst. Vehicle drivability and engine idle quality 
concerns tend to limit the amount of spark retard and/or increased idle 
speed that a manufacturer can use to accelerate catalyst warm up. These 
strategies or, more correctly, the systems used to employ these 
strategies--the ignition system for spark retard and the idle control 
system for control of engine speed--are normally monitored only after 
engine warm-up. Therefore, any malfunctions that might occur during the 
cold start event may not be detected by the OBD system. This could have 
significant emissions consequences due to the unknown loss of emissions 
control during the time following engine startup.
    This concern is exacerbated by the high cost of precious metals--
the platinum group metals (PGM) platinum, palladium, and rhodium--which 
motivates industry to minimize their use in catalysts. To compensate 
for the resultant reduction in overall catalyst performance, 
manufacturers will likely use increasingly more aggressive cold start 
emission reduction strategies in an attempt to further reduce cold 
start emissions. These strategies must be successful--and be properly 
monitored--to meet the more stringent 2008 emissions standards and to 
maintain low emissions in-use.
b. Cold Start Emission Reduction Strategy Monitoring Requirements
    We are proposing that, if an engine incorporates an engine control 
strategy specifically to reduce cold start emissions, the OBD system 
must monitor the key components (e.g., idle air control valve), other 
than the secondary air system, while the control strategy is active to 
ensure that the control strategy is operating properly. Secondary air 
systems would have to be monitored separately as discussed in section 
II.C.5.
    The OBD system would be required to detect a malfunction prior to 
any failure or deterioration of the individual components associated 
with the cold start emissions reduction control strategy that would 
cause an engine's emissions to exceed the emissions thresholds for 
``other monitors'' as shown in Table II.C-1. For components where no 
failure or deterioration of the component used by the cold start 
emission reduction strategy could result in an engine's emissions 
exceeding the applicable emissions thresholds, the individual 
components would have to be monitored for proper functional response as 
described in section II.D.4 while the control strategy is active.
    Manufacturers would be required to establish the appropriate 
malfunction criteria based on data from one or more representative 
engine(s). Further, manufacturers would be required to provide an 
engineering evaluation for establishing the malfunction criteria for 
the remainder of the manufacturer's product line. An annual evaluation 
of these criteria by the Administrator may not be necessary provided 
the manufacturer can demonstrate that any technological changes from 
one year to the next do not affect the previously approved malfunction 
criteria.
c. Cold Start Emission Reduction Strategy Monitoring Conditions
    We are proposing that manufacturers define the monitoring 
conditions for

[[Page 3229]]

malfunctions of the cold start emissions reduction strategy such that 
the minimum performance ratio requirements discussed in section II.E 
would be met.
d. Cold Start Emission Reduction Strategy MIL Illumination and DTC 
Storage
    We are proposing the general requirements for MIL illumination and 
DTC storage as discussed in section II.A.2.
5. Secondary Air System Monitoring
a. Background
    Secondary air systems--expected to be used on gasoline engines 
only--are used to reduce cold start emissions of hydrocarbons and 
carbon monoxide. Many of today's engines operate near stoichiometry 
after a cold engine start. However, the future more stringent emission 
standards may require the addition of a secondary air system in 
combination with a richer than stoichiometric cold start mixture. Such 
an approach could quickly warm up the catalyst for improved cold start 
emissions performance.
    Secondary air systems typically consist of an electric air pump, 
various hoses, and check valves to deliver outside air to the exhaust 
system upstream of the catalytic converter(s). This system usually 
operates only after a cold engine start and usually for only a brief 
period of time. When the electric air pump is operating, fresh air is 
delivered into the exhaust where it mixes with and ignites any unburned 
fuel. This serves to warm up the catalyst far more rapidly than would 
otherwise occur. Any problems that might occur in the field--corroded 
check valves, damaged tubing and hoses, malfunctioning air switching 
valves--could cause cold start emissions performance to suffer. 
Therefore, monitoring is needed given the importance of a properly 
functioning secondary air system to emissions performance.
b. Secondary Air System Monitoring Requirements
    We are proposing that the OBD system on engines equipped with any 
form of secondary air delivery system be required to monitor the proper 
functioning of the secondary air delivery system, including all air 
switching valve(s). The individual electronic components (e.g., 
actuators, valves, sensors) in the secondary air system would have to 
be monitored in accordance with the comprehensive component 
requirements discussed in section II.D.4.
i. Secondary Air System Low Flow Malfunctions
    We are proposing that the OBD system detect a secondary air system 
malfunction prior to a decrease from the manufacturer's specified air 
flow during normal operation that would cause an engine's emissions to 
exceed the emissions thresholds for ``other monitors'' as shown in 
Table II.C-1.\38\ For engines in which no deterioration or failure of 
the secondary air system would result in an engine's emissions 
exceeding any of the applicable emissions thresholds, the OBD system 
would have to detect a malfunction when no detectable amount of air 
flow is delivered during normal operation of the secondary air system.
---------------------------------------------------------------------------

    \38\ For purposes of secondary air system malfunctions, ``air 
flow'' is defined as the air flow delivered by the secondary air 
system to the exhaust system. For engines using secondary air 
systems with multiple air flow paths/distribution points, the air 
flow to each bank (i.e., a group of cylinders that share a common 
exhaust manifold, catalyst, and control sensor) must be monitored in 
accordance with these malfunction criteria. Also, ``normal 
operation'' is defined as the condition where the secondary air 
system is activated during catalyst and/or engine warm-up following 
engine start. ``Normal operation'' does not include the condition 
where the secondary air system is intrusively turned on solely for 
the purpose of monitoring.
---------------------------------------------------------------------------

ii. Secondary Air System High Flow Malfunctions
    We are proposing that the OBD system detect a secondary air system 
malfunction prior to an increase from the manufacturer's specified air 
flow during normal operation that would cause an engine's emissions to 
exceed the emissions thresholds for ``other monitors'' as shown in 
Table II.C-1.\39\ For engines in which no deterioration or failure of 
the secondary air system would result in an engine's emissions 
exceeding any of the applicable emissions thresholds, the OBD system 
would have to detect a malfunction when no detectable amount of air 
flow is delivered during normal operation of the secondary air system.
---------------------------------------------------------------------------

    \39\ Ibid.
---------------------------------------------------------------------------

c. Secondary Air System Monitoring Conditions
    We are proposing that manufacturers define the monitoring 
conditions for malfunctions of the secondary air system such that the 
minimum performance ratio requirements discussed in section II.E would 
be met. For purposes of tracking and reporting as required in section 
II.E, all monitors used to detect malfunctions of the secondary air 
system during its normal operation must be tracked separately but 
reported as a single set of values as specified in section II.E
d. Secondary Air System MIL Illumination and DTC Storage
    We are proposing the general requirements for MIL illumination and 
DTC storage as discussed in section II.A.2.
6. Catalytic Converter Monitoring
a. Background
    Three-way catalysts are one of the most important emission-control 
components on gasoline engines. They consist of ceramic or metal 
substrates coated with the one or more of the platinum group metals 
(PGM) platinum, palladium, and rhodium. These PGMs are dispersed within 
an alumina washcoat containing ceria, and the substrates are mounted in 
a stainless steel container in the vehicle exhaust system. Three-way 
catalysts are capable of oxidizing HC emissions, oxidizing CO 
emissions, and reducing NOX emissions, hence the term three-
way.
    While continuous improvements to catalysts have increased their 
durability, their performance still deteriorates, especially when 
subjected to very high temperatures. Such high temperatures can be 
caused by, among other factors, engine misfire which results in 
unburned fuel and air entering and igniting in the catalyst. Exposure 
to such high temperatures will result in reduced catalyst conversion 
efficiency. Catalyst efficiency can also deteriorate via poisoning if 
exposed to lead, phosphorus, or high sulfur levels. Catalysts can also 
fail by mechanical means such as excessive vibration. Given its 
importance to emissions control and the many factors that can reduce 
its effectiveness, the catalyst is one of the most important components 
to be monitored.
b. Catalytic Converter Monitoring Requirements
    We are proposing that the OBD system monitor the catalyst system 
for proper conversion capability. Specifically, the OBD system would be 
required to detect a catalyst system malfunction when the catalyst 
system's conversion capability decreases to the point that any of the 
following occurs:
     NMHC and/or NOX emissions exceed the emissions 
thresholds for the ``catalytic converter system'' as shown in Table 
II.C-1.
    For purposes of determining the catalyst system malfunction 
criteria the manufacturer would be required to use a catalyst system 
deteriorated to the malfunction criteria using methods established by 
the manufacturer to

[[Page 3230]]

represent real world catalyst deterioration under normal and 
malfunctioning operating conditions. The malfunction criteria must be 
established by using a catalyst system with all monitored and 
unmonitored catalysts simultaneously deteriorated to the malfunction 
criteria.\40\ For engines using fuel shutoff to prevent over-fueling 
during misfire conditions (see section II.C.2), the malfunction 
criteria could be established using a catalyst system with all 
monitored catalysts simultaneously deteriorated to the malfunction 
criteria and all unmonitored catalysts deteriorated to the end of the 
engine's useful life.
---------------------------------------------------------------------------

    \40\ The unmonitored portion of the catalyst system would be 
that portion downstream of the sensor(s) used for catalyst 
monitoring.
---------------------------------------------------------------------------

c. Catalytic Converter Monitoring Conditions
    We are proposing that manufacturers define the monitoring 
conditions for malfunctions of the catalytic converter system such that 
the minimum performance ratio requirements discussed in section II.E 
would be met. For purposes of tracking and reporting as required in 
section II.E, all monitors used to detect malfunctions of the catalytic 
converter system during its normal operation must be tracked separately 
but reported as a single set of values as specified in section II.E.
d. Catalytic Converter MIL Illumination and DTC Storage
    We are proposing the general requirements for MIL illumination and 
DTC storage as discussed in section II.A.2. Note that the monitoring 
method for the catalyst(s) would have to be capable of detecting all 
instances, except diagnostic self-clearing, when a catalyst DTC has 
been cleared but the catalyst has not been replaced (e.g., catalyst 
over temperature histogram approaches are not acceptable).
7. Evaporative Emission Control System Monitoring
a. Background
    The evaporative emission control system controls HC emissions that 
would otherwise evaporate from the vehicle's fuel tank and fuel lines. 
Should any leak develop in the evaporative emission control system--
e.g., a disconnected hose--the HC emissions can be quite high and well 
over the evaporative emissions standards. Additionally, evaporative 
purge system defects--e.g., deteriorated vacuum lines, damaged 
canisters, non-functioning purge control valves--may occur which could 
also result in very high evaporative emissions.
b. Evaporative System Monitoring Requirements
    We are proposing that the OBD system verify purge flow from the 
evaporative system and detect any vapor leaks from the complete 
evaporative system, excluding the tubing and connections between the 
purge valve and the intake manifold. Individual components of the 
evaporative system (e.g. valves, sensors) must be monitored in 
accordance with the comprehensive components requirements discussed in 
section II.D.4.
    The OBD system would be required to detect an evaporative system 
malfunction when any of the following conditions exist:
     No purge flow from the evaporative system to the engine 
can be detected by the OBD system (i.e., the ``purge flow'' 
requirement); or
     For the 2010 and later model years, the complete 
evaporative system contains a leak or leaks that cumulatively are 
greater than or equal to a leak caused by a 0.150 inch diameter orifice 
(i.e., the ``system leak'' requirement).\41\
---------------------------------------------------------------------------

    \41\ In their HDOBD regulation, 13 CCR 1971.1, CARB defines 
``orifice'' as an O'Keefe Controls Co. precision metal ``Type B'' 
orifice with NPT connections with a diameter of the specified 
dimension (e.g., part number B-31-SS for a stainless steel 0.031 
inch diameter orifice).
---------------------------------------------------------------------------

    If the most reliable monitoring method available cannot reliably 
detect a system leak as specified above, a manufacturer may design 
their system to detect a larger leak. The manufacturer would be 
required to provide data and/or engineering analyses that demonstrate 
the inability of the monitor to reliably detect the required leak and 
their justification for detecting at their proposed orifice size. 
Further, if the manufacturer can demonstrate that leaks of the required 
size cannot cause evaporative or running loss emissions to exceed 1.5 
times the applicable evaporative emissions standards, the Administrator 
would revise upward the required leak size to the size demonstrated by 
the manufacturer that would result in emissions exceeding 1.5 times the 
standards.
c. Evaporative System Monitoring Conditions
    We are proposing that manufacturers define the monitoring 
conditions for both purge flow and system leak malfunctions such that 
the minimum performance ratio requirements discussed in section II.E 
would be met. For purposes of tracking and reporting as required in 
section II.E, all monitors used to detect system leak malfunctions must 
be tracked separately but reported as a single set of values as 
specified in section II.E.
    Manufacturers may disable or abort an evaporative emission control 
system monitor when the fuel tank level is over 85 percent of nominal 
tank capacity or during a refueling event. Manufacturers may design 
their evaporative emission control system monitor such that it executes 
only during drive cycles determined by the manufacturer to be cold 
starts if such a condition is needed to ensure reliable monitoring. The 
manufacturer would have to provide data and/or an engineering 
evaluation demonstrating that a reliable check can only be made on 
drive cycles when the cold start criteria are satisfied. However, the 
manufacturer may not determine a cold start solely on the basis that 
ambient temperature is higher than engine coolant temperature at engine 
start. Lastly, manufacturers would be allowed to disable temporarily 
the evaporative purge system to perform an evaporative system leak 
check.
d. Evaporative System MIL Illumination and DTC Storage
    We are proposing the general requirements for MIL illumination and 
DTC storage as discussed in section II.A.2, with an exception for leaks 
associated with the fuel filler cap. If the OBD system is capable of 
discerning that a system leak is being caused by a missing or 
improperly secured fuel filler cap, the manufacturer is not required to 
illuminate the MIL or store a DTC provided the vehicle is equipped with 
an alternative indicator for notifying the vehicle operator of the fuel 
filler cap ``malfunction.'' The alternative indicator would have to be 
of sufficient illumination and location to be readily visible to the 
vehicle operator under all lighting conditions. However, if the vehicle 
is not equipped with an alternative indicator and, instead, the MIL is 
illuminated to inform the operator of the ``malfunction,'' the MIL may 
be extinguished and the corresponding DTC(s) erased once the OBD system 
has verified that the fuel filler cap has been securely fastened and 
the MIL has not been commanded ON for any other type of malfunction. 
The Administrator may approve other strategies provided the 
manufacturer was able to demonstrate that the vehicle operator would be 
promptly notified of the missing or improperly secured fuel filler cap 
and that the notification would reasonably result in corrective action 
being undertaken.

[[Page 3231]]

8. Exhaust Gas Sensor Monitoring
a. Background
    Exhaust gas sensors (e.g., oxygen sensors, air-fuel ratio (A/F) 
sensors) are a critical element of the emissions control system on 
gasoline engines. In addition to maintaining a stoichiometric air-fuel 
mixture and, thus, helping to achieve the lowest possible emissions, 
these sensors are also used for enhancing the performance of several 
emission control technologies--e.g., catalysts, EGR systems). Many 
modern vehicles control the fuel supply with an oxygen sensor feedback 
system to maintain stoichiometry. Oxygen sensors are located typically 
in the exhaust system upstream and downstream of the catalytic 
converters. The front, or upstream, oxygen sensor is used generally for 
fuel control. The rear, or downstream, oxygen sensor is used generally 
for adjusting the front oxygen sensor signal as it drifts slightly with 
age related deterioration--often referred to as fuel trimming--and for 
onboard monitoring the catalyst system. Many vehicles use A/F sensors 
in lieu of the more conventional oxygen sensors since A/F sensors 
provide a precise reading of the actual air-fuel ratio.
    We expect that heavy-duty gasoline manufacturers will use both of 
these types of sensors to optimize their emissions control strategies 
and to satisfy many of the proposed heavy-duty OBD monitoring 
requirements--fuel system monitoring, catalyst monitoring, EGR system 
monitoring. Since exhaust gas sensors can be a critical component of an 
engine's fuel and emissions control system, their proper performance 
needs to be assured to maintain low emissions. Thus, any malfunction 
that adversely affects the performance of any of these exhaust gas 
sensors should be detected by the OBD system.
b. Exhaust Gas Sensor Monitoring Requirements
    We are proposing that the OBD system monitor the output signal, 
response rate, and any other parameter that could affect emissions of 
all primary (i.e., fuel control) exhaust gas sensors for malfunction. 
Both the lean to rich and rich to lean response rates must be 
monitored. In addition, we are proposing that the OBD system monitor 
all secondary exhaust gas sensors (i.e., those used for fuel trimming 
or as a monitoring device for another system) for proper output signal, 
activity, and response rate. For engines equipped with heated exhaust 
gas sensors, the OBD system would be required to monitor the sensor 
heater for proper performance.
i. Primary Exhaust Gas Sensors
    We are proposing that the OBD system detect a malfunction prior to 
any failure or deterioration of the exhaust gas sensor output voltage, 
resistance, impedance, current, response rate, amplitude, offset, or 
other characteristic(s) (including drift or bias corrected for by 
secondary sensors) that would cause an engine's emissions to exceed the 
emissions thresholds for ``other monitors'' as shown in Table II.C-1. 
The OBD system would also be required to detect the following exhaust 
gas sensor malfunctions:
     Those caused by either a lack of circuit continuity or 
out-of-range values.
     Those where a sensor failure or deterioration causes the 
fuel system to stop using that sensor as a feedback input (e.g., causes 
default or open-loop operation).
     Those where the sensor output voltage, resistance, 
impedance, current, amplitude, activity, or other characteristics are 
no longer sufficient for use as an OBD system monitoring device (e.g., 
for catalyst monitoring).
ii. Secondary Exhaust Gas Sensors
    We are proposing that the OBD system detect a malfunction prior to 
any failure or deterioration of the exhaust gas sensor voltage, 
resistance, impedance, current, response rate, amplitude, offset, or 
other characteristic(s) that would cause an engine's emissions to 
exceed the emissions thresholds for ``other monitors'' as shown in 
Table II.C-1. The OBD system would also be required to detect the 
following exhaust gas sensor malfunctions:
     Those caused by either a lack of circuit continuity or 
out-of-range values.
     Those where a sensor failure or deterioration causes the 
fuel system to stop using that sensor as a feedback input (e.g., causes 
default or open-loop operation).
     Those where the sensor output voltage, resistance, 
impedance, current, amplitude, activity, or other characteristics are 
no longer sufficient for use as an OBD system monitoring device (e.g., 
for catalyst monitoring).
iii. Exhaust Gas Sensor Heaters
    We are proposing that the OBD system detect a malfunction of the 
sensor heater performance when the current or voltage drop in the 
heater circuit is no longer within the manufacturer's specified limits 
for normal operation (i.e., within the criteria required by the 
component vendor for heater circuit performance at high mileage). The 
manufacturer may use other malfunction criteria for heater performance 
malfunctions. To do so, the manufacturer would be required to submit 
data and/or engineering analyses that demonstrate that the monitoring 
reliability and timeliness would be equivalent to the criteria stated 
here.
    In addition, the OBD system would be required to detect 
malfunctions of the heater circuit including open or short circuits 
that conflict with the commanded state of the heater (e.g., shorted to 
12 Volts when commanded to 0 Volts (ground)).
c. Exhaust Gas Sensor Monitoring Conditions
i. Primary Exhaust Gas Sensors
    We are proposing that manufacturers define the monitoring 
conditions for primary exhaust gas sensor malfunctions causing 
exceedance of the applicable thresholds and/or inability to perform as 
an OBD monitoring device such that the minimum performance ratio 
requirements discussed in section II.E would be met. For purposes of 
tracking and reporting as required in section II.E, all such monitors 
must be tracked separately but reported as a single set of values as 
specified in section II.E.
    Monitoring for primary exhaust gas sensor malfunctions related to 
circuit continuity, out-of-range, and open-loop operation must be done 
continuously with the exception that manufacturers may disable 
continuous exhaust gas sensor monitoring when an exhaust gas sensor 
malfunction cannot be distinguished from other effects. As an example, 
a manufacturer may disable monitoring for out-of-range on the low side 
during conditions where fuel has been cut (i.e., shut off temporarily). 
To do so, the manufacturer would have to submit data and/or engineering 
analyses that demonstrate that a properly functioning sensor cannot be 
distinguished from a malfunctioning sensor and that the disablement 
interval is limited only to that necessary for avoiding a false 
detection.
ii. Secondary Exhaust Gas Sensors
    We are proposing that manufacturers define the monitoring 
conditions for secondary exhaust gas sensor malfunctions causing 
exceedance of the applicable emissions thresholds, lack of circuit 
continuity, and/or inability to perform as an OBD monitoring device 
such that the minimum performance ratio requirements discussed in 
section II.E would be met.
    Monitoring for secondary exhaust gas sensor malfunctions related to 
out-of-

[[Page 3232]]

range and open loop operation must be done continuously with the 
exception that manufacturers may disable continuous exhaust gas sensor 
monitoring when an exhaust gas sensor malfunction cannot be 
distinguished from other effects. As an example, a manufacturer may 
disable monitoring for out-of-range on the low side during conditions 
where fuel has been cut (i.e., shut off temporarily). To do so, the 
manufacturer would have to submit data and/or engineering analyses that 
demonstrate that a properly functioning sensor cannot be distinguished 
from a malfunctioning sensor and that the disablement interval is 
limited only to that necessary for avoiding a false detection.
iii. Sensor Heaters
    We are proposing that manufacturers define monitoring conditions 
for sensor heater performance malfunctions such that the minimum 
performance ratio requirements discussed in section II.E would be met. 
Monitoring for sensor heater circuit malfunctions must be done 
continuously.
d. Exhaust Gas Sensor MIL Illumination and DTC Storage
    We are proposing the general requirements for MIL illumination and 
DTC storage as discussed in section II.A.2.

D. Monitoring Requirements and Timelines for Other Diesel and Gasoline 
Systems

1. Variable Valve Timing and/or Control (VVT) System Monitoring
a. Background
    Variable valve timing (VVT) and/or control systems are used 
primarily to optimize engine performance and have many advantages over 
conventional valve control. Instead of opening and closing the valves 
by fixed amounts and at fixed times, VVT controls can vary the timing 
of valve opening/closing and vary the effective size of the valve 
opening itself (in some systems) depending on the driving conditions 
(e.g., high engine speed and load). This feature permits a better 
compromise between performance, driveability, and emissions than 
conventional systems. With more stringent NOX emission 
standards being phased in, more vehicles are anticipated to use VVT. By 
doing so, some exhaust gas can be retained in the combustion chamber 
thereby reducing peak combustion temperatures and, hence, 
NOX emissions (known as ``internal EGR'').
b. VVT and/or Control System Monitoring Requirements
    We are proposing that the OBD system monitor the VVT system on 
engines so equipped for target error and slow response malfunctions. 
The individual electronic components (e.g., actuators, valves, sensors) 
that are used in the VVT system must be monitored in accordance with 
the comprehensive components requirements in section II.D.4.
i. VVT Target Error Malfunctions
    We are proposing that the OBD system detect a malfunction prior to 
any failure or deterioration in the capability of the VVT system to 
achieve the commanded valve timing and/or control within a crank angle 
and/or lift tolerance that would cause an engine's emissions to exceed 
the emissions thresholds for ``other monitors'' as shown in Table II.B-
1 for diesel engines or Table II.C-1 for gasoline engines. For engines 
in which no failure or deterioration of the VVT system could result in 
an engine's emissions exceeding the applicable emissions thresholds, 
the OBD system would have to detect a malfunction of the VVT system 
when proper functional response of the system to computer commands does 
not occur.
ii. VVT Slow Response Malfunctions
    We are proposing that the OBD system detect a malfunction prior to 
any failure or deterioration in the capability of the VVT system to 
achieve the commanded valve timing and/or control within a 
manufacturer-specified time that would cause an engine's emissions to 
exceed the emissions thresholds for ``other monitors'' as shown in 
Table II.B-1 for diesel engines or Table II.C-1 for gasoline engines. 
For engines in which no failure or deterioration of the VVT system 
could result in an engine's emissions exceeding the applicable 
emissions thresholds, the OBD system would have to detect a malfunction 
of the VVT system when proper functional response of the system to 
computer commands does not occur.
c. VVT and/or Control System Monitoring Conditions
    We are proposing that manufacturers define the monitoring 
conditions for VVT target error or slow response malfunctions such that 
the minimum performance ratio requirements discussed in section II.E 
would be met with the exception that monitoring shall occur every time 
the monitoring conditions are met during the driving cycle rather than 
once per driving cycle as required for most monitors. For purposes of 
tracking and reporting as required in section II.E, all monitors used 
to detect all VVT related malfunctions would have to be tracked 
separately but reported as a single set of values as specified in 
section II.E.\42\
---------------------------------------------------------------------------

    \42\ For specific components or systems that have multiple 
monitors that are required to be reported (e.g., exhaust gas sensor 
bank 1 may have multiple monitors for sensor response or other 
sensor characteristics), the OBD system must separately track 
numerators and denominators for each of the specific monitors and 
report only the corresponding numerator and denominator for the 
specific monitor that has the lowest numerical ratio. If two or more 
specific monitors have identical ratios, the corresponding numerator 
and denominator for the specific monitor that has the highest 
denominator shall be reported for the specific component.
---------------------------------------------------------------------------

d. VVT and/or Control System MIL Illumination and DTC Storage
    We are proposing the general requirements for MIL illumination and 
DTC storage as discussed in section II.A.2.
2. Engine Cooling System Monitoring
a. Background
    We are concerned about two elements of the engine cooling system. 
These elements are the thermostat and the engine coolant temperature 
sensor. Manufacturers typically use a thermostat to control the flow of 
coolant through the radiator and around the engine. During a cold 
engine start, the thermostat is closed typically which prevents the 
flow of coolant and serves to promote more rapid warm-up of the engine. 
As the coolant approaches a specific temperature, the thermostat begins 
to open allowing circulation of coolant through the radiator and around 
the engine. The thermostat then acts to regulate the coolant to the 
specified temperature. If the temperature rises above the regulated 
temperature, the thermostat opens further to allow more coolant to 
circulate, thus reducing the temperature. If the temperature drops 
below the regulated temperature, the thermostat partially closes to 
reduce the amount of coolant circulating, thereby increasing the 
temperature. If a thermostat malfunctions in such a manner that it does 
not adequately restrict coolant flow during vehicle warm-up, an 
increase in emissions could occur due to prolonged operation of the 
vehicle at temperatures below the stabilized, warmed-up value. This is 
particularly true at lower ambient temperatures--50 degrees Fahrenheit 
and below--but not so low that they are rare in the U.S. Equally 
important is that the engine coolant temperature is often used as an 
enable criterion for many OBD monitors. If the engine's coolant 
temperature does not reach the

[[Page 3233]]

manufacturer-specified warmed-up value, such monitors would be 
effectively disabled, perhaps indefinitely, and would, therefore, never 
detect malfunctions.
    Closely linked with the thermostat is the engine coolant 
temperature (ECT) sensor. Manufacturers typically use an ECT sensor as 
an input for many of the emission-related engine control systems. For 
gasoline engines, the ECT sensor is often one of the most important 
factors in determining when to begin closed-loop fuel control. If the 
engine coolant does not warm-up sufficiently, closed-loop fuel control 
is usually not engaged and the vehicle remains in open-loop fuel 
control. Since open-loop fuel control does not provide the precision of 
closed-loop control, the result is increased emissions levels. For 
diesel engines, the ECT sensor is often used to engage closed-loop 
control of the EGR system. Similar to closed-loop fuel control on 
gasoline engines, if the coolant temperature does not warm up, closed-
loop control of the EGR system would not engage which would result in 
increased emissions levels. In addition, for both gasoline and diesel 
engines, the ECT sensor may be used to enable many of the monitors that 
are being proposed. Such monitors would be effectively disabled and 
incapable of detecting malfunctions should the ECT sensor itself 
malfunction.
b. Engine Cooling System Monitoring Requirements
    We are proposing that the OBD system monitor the thermostat on 
engines so equipped for proper operation. We are also proposing that 
the OBD system monitor the ECT sensor for circuit continuity, out-of-
range values, and rationality faults. For engines that use an approach 
other than the cooling system and ECT sensor--e.g., oil temperature, 
cylinder head temperature--for an indication of engine operating 
temperature for emission control purposes (e.g., to modify spark or 
fuel injection timing or quantity), the manufacturer may forego cooling 
system monitoring in favor of monitoring the components or systems used 
in their approach. To do so, the manufacturer would be required to 
submit data and/or engineering analyses that demonstrate that their 
monitoring plan is as reliable and effective as the monitoring required 
for the engine cooling system.
i. Thermostat Monitoring Requirements
    We are proposing that the OBD system detect a thermostat 
malfunction if, within the manufacturer specified time interval 
following engine start, any of the following conditions occur:
     The coolant temperature does not reach the highest 
temperature required by the OBD system to enable other diagnostics;
     The coolant temperature does not reach a warmed-up 
temperature within 20 degrees Fahrenheit of the manufacturer's nominal 
thermostat regulating temperature. The manufacturer may use a lower 
temperature for this criterion provided the manufacturer can 
demonstrate that the fuel, spark timing, and/or other coolant 
temperature-based modification to the engine control strategies would 
not cause an emissions increase greater than or equal to 50 percent of 
any of the applicable emissions standards.
    The time interval specified by the manufacturer would have to be 
supported by the manufacturer via data and/or engineering analyses 
demonstrating that it provides robust monitoring and minimizes the 
likelihood of other OBD monitors being disabled. The manufacturer may 
use alternative malfunction criteria that are a function of temperature 
at engine start on engines that do not reach the temperatures specified 
in the malfunction criteria when the thermostat is functioning 
properly. To do so, the manufacturer would be required to submit data 
and/or engineering analyses that demonstrate that a properly operating 
system does not reach the specified temperatures and that the 
possibility is minimized for cooling system malfunctions to go 
undetected and disable other OBD monitors. In some cases, a 
manufacturer may forgo thermostat monitoring if the manufacturer can 
demonstrate that a malfunctioning thermostat cannot cause a measurable 
increase in emissions during any reasonable driving condition nor cause 
any disablement of other OBD monitors.
ii. Engine Coolant Temperature Sensor Monitoring Requirements
    We are proposing that the OBD system detect an ECT sensor 
malfunction when a lack of circuit continuity or an out-of-range value 
occurs. We are also proposing that the OBD system detect if, within the 
manufacturer specified time interval following engine start, the ECT 
sensor does not achieve the highest stabilized minimum temperature that 
is needed to initiate closed-loop/feedback control of all affected 
emission control systems (e.g., fuel system, EGR system). The 
manufacturer specified time interval would have to be a function of the 
engine coolant temperature and/or intake air temperature at startup. 
The manufacturer time interval would also have to be supported by the 
manufacturer via data and/or engineering analyses demonstrating that it 
provides robust monitoring and minimizes the likelihood of other OBD 
monitors being disabled. Manufacturers may forego the requirement to 
detect the ``time to closed loop/feedback enable temperature'' 
malfunction if the manufacturer does not use engine coolant temperature 
or the ECT sensor to enable closed-loop/feedback control of any 
emission control systems.
    We are also proposing that, to the extent feasible when using all 
available information, the OBD system must detect a malfunction if the 
ECT sensor inappropriately indicates a temperature below the highest 
minimum enable temperature required by the OBD system to enable other 
monitors. For example, an OBD system that requires an engine coolant 
temperature greater than 140 degrees Fahrenheit prior to enabling an 
OBD monitor must detect malfunctions that cause the ECT sensor to 
indicate inappropriately a temperature below 140 degrees Fahrenheit. 
Manufacturers may forego such monitoring within temperature regions in 
which the thermostat monitor or the ECT sensor ``time to reach closed-
loop/feedback enable temperature'' monitor would detect this ``stuck in 
a range below the highest minimum enable temperature'' ECT sensor 
malfunction.
    Lastly, we are proposing that, to the extent feasible when using 
all available information, the OBD system must detect a malfunction if 
the ECT sensor inappropriately indicates a temperature above the lowest 
maximum enable temperature required by the OBD system to enable other 
monitors. For example, an OBD system that requires an engine coolant 
temperature less than 90 degrees Fahrenheit at startup prior to 
enabling an OBD monitor must detect malfunctions that cause the ECT 
sensor to indicate inappropriately a temperature above 90 degrees 
Fahrenheit. Manufacturers may forego such monitoring within temperature 
regions in which the thermostat monitor, the ECT sensor ``time to reach 
closed-loop/feedback enable temperature'' monitor, or the ECT sensor 
``stuck in a range below the highest minimum enable temperature'' 
monitor would detect this ECT sensor ``stuck in a range above the 
lowest maximum enable temperature'' ECT sensor malfunction. The 
manufacturer may also forego such monitoring if the MIL would be 
illuminated for entering a ``limp home'' or default mode of

[[Page 3234]]

operation--e.g., for an over temperature protection strategy--as 
discussed in section II.A.2. Manufacturers may also forego this 
monitoring within temperature regions where the temperature gauge 
indicates a temperature in the engine overheating ``red zone'' should 
the vehicle have a temperature gauge on the instrument panel that 
displays the same temperature information as used by the OBD system 
(note that a temperature gauge would be required, not a temperature 
warning light).
c. Engine Cooling System Monitoring Conditions
i. Thermostat Monitoring Conditions
    We are proposing that manufacturers define the monitoring 
conditions for thermostat malfunctions in accordance with the general 
monitoring conditions for all engines described in section II.A.3. 
Additionally, monitoring for thermostat malfunctions would have to be 
done once per drive cycle on every drive cycle in which the ECT sensor 
indicates, at engine start, a temperature lower than the temperature 
established as the malfunction criteria in section II.D.2.b.i. 
Manufacturers would be allowed to disable thermostat monitoring at 
ambient engine start temperatures below 20 degrees Fahrenheit. 
Manufacturers may suspend or disable thermostat monitoring if the 
engine is subjected to conditions that could lead to false diagnosis 
(e.g., engine operation at idle for more than 50 percent of the warm-up 
time and/or hot restart conditions). To do so, the manufacturer must 
submit data and/or engineering analyses that demonstrate that the 
suspension or disablement is necessary. In general, the manufacturer 
would not be allowed to suspend or disable the thermostat monitor on 
engine starts where the engine coolant temperature at engine start is 
more than 35 degrees Fahrenheit lower than the thermostat malfunction 
threshold temperature.
ii. Engine Coolant Temperature Sensor Monitoring Conditions
    We are proposing that monitoring for ECT sensor circuit continuity 
and out-of-range malfunctions be done continuously. Manufacturers would 
be allowed to disable continuous ECT sensor monitoring when an ECT 
sensor malfunction cannot be distinguished from other effects. To do 
so, the manufacturer would have to submit test data and/or engineering 
evaluation that demonstrate that a properly functioning sensor cannot 
be distinguished from a malfunctioning sensor and that the disablement 
interval is limited only to that necessary for avoiding false 
detection.
    We are also proposing that manufacturers define the monitoring 
conditions for ``time to reach closed-loop/feedback enable 
temperature'' malfunctions in accordance with the general monitoring 
conditions for all engines described in section II.A.3. Additionally, 
monitoring for ``time to reach closed-loop/feedback enable 
temperature'' malfunctions would have to be conducted once per drive 
cycle on every drive cycle in which the ECT sensor at engine start 
indicates a temperature lower than the closed-loop enable temperature 
(i.e., all engine start temperatures greater than the ECT sensor out-
of-range low temperature and less than the closed-loop enable 
temperature). Manufacturers would be allowed to suspend or delay the 
``time to reach closed-loop/feedback enable temperature'' monitor if 
the engine is subjected to conditions that could lead to false 
diagnosis (e.g., vehicle operation at idle for more than 50 to 75 
percent of the warm-up time).
    We are also proposing that manufacturers define the monitoring 
conditions for ECT sensor ``stuck in a range below the highest minimum 
enable temperature'' and ``stuck in a range above the lowest maximum 
enable temperature'' malfunctions in accordance with the general 
monitoring conditions for all engines described in section II.A.3 and 
in accordance with the minimum performance ratio requirements discussed 
in section II.E.
d. Engine Cooling System MIL Illumination and DTC Storage
    We are proposing the general requirements for MIL illumination and 
DTC storage as discussed in section II.A.2.
3. Crankcase Ventilation System Monitoring
a. Background
    Crankcase emissions are the pollutants emitted in the gases that 
are vented from an engine's crankcase. These gases are also referred to 
as ``blowby gases'' because they result from engine exhaust from the 
combustion chamber ``blowing by'' the piston rings into the crankcase. 
These gases are vented to prevent high pressures from occurring in the 
crankcase. Our emission standards have historically prohibited 
crankcase emissions from all highway engines except turbocharged heavy-
duty diesel engines. The most common way to eliminate crankcase 
emissions has been to vent the blowby gases into the engine air intake 
system, so that the gases can be recombusted. We made the exception for 
turbocharged heavy-duty diesel engines in the past because of concerns 
about fouling that could occur by routing the diesel particulates 
(including engine oil) into the turbocharger and aftercooler. Newly 
developed closed crankcase filtration systems specifically designed for 
turbocharged heavy-duty diesel engines now allow the crankcase gases to 
be captured.
    In general, the crankcase ventilation system consists of a fresh 
air inlet hose, a crankcase vapor outlet hose, and a crankcase 
ventilation valve to control the flow through the system. Fresh air is 
introduced to the crankcase via the inlet (typically a connection from 
the intake air cleaner assembly). On the opposite side of the 
crankcase, vapors are vented from the crankcase through the valve by 
way of the outlet hose and then to the intake manifold. On gasoline 
engines, the intake manifold provides the vacuum that is needed to 
accomplish the circulation while the engine is running.
    For gasoline engines, the valve is used to regulate the amount of 
flow based on engine speed. During low engine load operation (e.g., 
idle), the valve is nearly closed allowing only a small portion of air 
to flow through the system. With open throttle conditions, the valve 
opens to allow more air into the system. At high engine load operation 
(i.e., hard accelerations), the valve begins to close again, limiting 
air flow to a small amount. For most systems, a mechanical valve is all 
that is necessary to adequately regulate crankcase ventilation system 
air flow. The crankcase ventilation system on diesel engines, while 
slightly different than that for gasoline engines, has essentially the 
same purpose and function.
    We do not believe that failures involving cracked or deteriorated 
hoses have a significant impact on crankcase emissions because vapors 
are drawn into the engine by intake manifold vacuum which suggests that 
fresh air would be drawn into the cracked hose rather than dirty 
exhaust being blown out of the cracked hose. The more likely cause of 
crankcase ventilation system malfunctions and excess emissions is 
improper service or tampering of the system. Such failures include 
misrouted or disconnected hoses and missing valves. Of these failures, 
hose disconnections on the vapor vent side of the system and/or missing 
valves can cause harmful crankcase emissions to be vented directly to 
the atmosphere.

[[Page 3235]]

b. Crankcase Ventilation System Monitoring Requirements
    We are proposing that the OBD system monitor the crankcase 
ventilation system on engines so equipped for system integrity. Engines 
not equipped with crankcase ventilation systems would be exempt from 
monitoring the crankcase ventilation system.
    Specifically for diesel engines, the manufacturer would be required 
to submit a plan for the monitoring strategy, malfunction criteria, and 
monitoring conditions prior to OBD certification. The plan would have 
to demonstrate the effectiveness of the strategy to monitor the 
performance of the crankcase ventilation system to the extent feasible 
with respect to the malfunction criteria below and the monitoring 
conditions required by the monitor.
    We are proposing that the OBD system detect a malfunction of the 
crankcase ventilation system when a disconnection of the system occurs 
between either the crankcase and the crankcase ventilation valve, or 
between the crankcase ventilation valve and the intake manifold. 
Manufacturers may forego detecting a disconnection between the 
crankcase and the crankcase ventilation valve provided the manufacturer 
can demonstrate that the crankcase ventilation system is designed such 
that the crankcase ventilation valve is fastened directly to the 
crankcase in a manner that makes it significantly more difficult to 
remove the valve from the crankcase than to disconnect the line between 
the valve and the intake manifold (aging effects must be taken into 
consideration). Manufacturers may also forego detecting a disconnection 
between the crankcase and the crankcase ventilation valve for system 
designs that use tubing between the valve and the crankcase provided 
the manufacturer can demonstrate that the connections between the valve 
and the crankcase are: (1) Resistant to deterioration or accidental 
disconnection; (2) significantly more difficult to disconnect than the 
line between the valve and the intake manifold; and, (3) not subject to 
disconnection per the manufacturer's repair procedures for non-
crankcase ventilation system repair work. Lastly, manufacturers may 
forego detecting a disconnection between the crankcase ventilation 
valve and the intake manifold upon determining that the disconnection: 
(1) Causes the vehicle to stall immediately during idle operation; or, 
(2) is unlikely to occur due to a crankcase ventilation system design 
that is integral to the induction system (e.g., machined passages 
rather than tubing or hoses).
c. Crankcase Ventilation System Monitoring Conditions
    We are proposing that manufacturers define the monitoring 
conditions for crankcase ventilation system malfunctions in accordance 
with the general monitoring conditions for all engines described in 
section II.A.3, and the minimum performance ratio requirements 
discussed in section II.E.
d. Crankcase Ventilation System MIL Illumination and DTC Storage
    We are proposing the general requirements for MIL illumination and 
DTC storage as discussed in section II.A.2. The stored DTC need not 
specifically identify the crankcase ventilation system (e.g., a DTC for 
idle speed control or fuel system monitoring can be stored) if the 
manufacturer can demonstrate that additional monitoring hardware would 
be necessary to make this identification, and provided the 
manufacturer's diagnostic and repair procedures for the detected 
malfunction include directions to check the integrity of the crankcase 
ventilation system.
4. Comprehensive Component Monitors
a. Background
    Comprehensive components is a term meant to capture essentially 
every other emissions related component not discussed above. 
Specifically, it covers all other electronic engine components or 
systems not mentioned above that either can affect vehicle emissions or 
are used as part of the OBD diagnostic strategy for another monitored 
component or system. Comprehensive components are generally identified 
as input components--i.e., those that provide input directly or 
indirectly to the onboard computer--or as output components and/or 
systems--i.e., those that receive commands from the onboard computer. 
Typical examples of input components include temperature sensors and 
pressure sensors, while examples of output components and/or systems 
include the idle control system, glow plugs, and wait-to-start lamps.
    While a malfunctioning comprehensive component may not have as much 
impact on emissions as a malfunctioning major emissions-related 
component, it still could result in a measurable increase in emissions. 
The proper performance of these components can be critical to both the 
proper functioning of major emissions-related components, and to the 
accurate monitoring of those components or systems. Malfunctions of 
comprehensive components that go undetected by the OBD system may 
disable or adversely affect the robustness of other OBD monitors 
without any awareness by the operator that a problem exists. Due to the 
vital role these components play, monitoring them properly is extremely 
important.
b. Comprehensive Component Monitoring Requirements
    We are proposing that the OBD system monitor for malfunction any 
electronic engine components/systems not otherwise described in 
sections above that either provides input to (directly or indirectly) 
or receives commands from the onboard computer(s), and: (1) Can affect 
emissions during any reasonable in-use driving condition; or, (2) is 
used as part of the diagnostic strategy for any other monitored system 
or component.\43\
---------------------------------------------------------------------------

    \43\ When referring to ``comprehensive components'' and their 
monitors, ``electronic engine components/systems'' is not meant to 
include components/systems that are driven by the engine yet are not 
related to the control of the fueling, air handling, or emissions of 
the engine (e.g., PTO components, air conditioning system 
components, and power steering components are not included).
---------------------------------------------------------------------------

    Input components required to be monitored may include the crank 
angle sensor, knock sensor, throttle position sensor, cam position 
sensor, intake air temperature sensor, boost pressure sensor, manifold 
pressure sensor, mass air flow sensor, exhaust temperature sensor, 
exhaust pressure sensor, fuel pressure sensor, and fuel composition 
sensor (e.g., flexible fuel vehicles). Output components/systems 
required to be monitored may include the idle speed control system, 
glow plug system, variable length intake manifold runner systems, 
supercharger or turbocharger electronic components, heated fuel 
preparation systems, the wait-to-start lamp on diesel applications, and 
the MIL. The manufacturer would be responsible for determining which 
input and output components/systems could affect emissions during any 
reasonable in-use driving condition. The manufacturer would be allowed 
to make this determination based on data or engineering judgment. 
However, if the Administrator reasonably believes that a manufacturer 
has incorrectly determined that a component/system cannot affect 
emissions, the manufacturer may be required to provide emissions data 
showing that the component/system, when malfunctioning and installed in 
a suitable test engine, does not have an emissions effect. Such 
emissions data may be requested for any reasonable driving condition.

[[Page 3236]]

i. Input Components
    We are proposing that the OBD system detect malfunctions of input 
components caused by a lack of circuit continuity, out-of-range values, 
and, where feasible, improper rationality. To the extent feasible, the 
rationality diagnostics should verify that a sensor's input to the 
onboard computer is neither inappropriately high nor inappropriately 
low (i.e., ``two-sided'' diagnostics should be used). Also to the 
extent feasible, the OBD system should detect and store different DTCs 
that distinguish rationality malfunctions from lack of circuit 
continuity malfunctions and out-of-range values. For lack of circuit 
continuity malfunctions and out-of-range values, the OBD system should 
detect and store different DTCs for each distinct malfunction (e.g., 
out-of-range low, out-of-range high, open circuit). The OBD system is 
not required to store separate DTCs for lack of circuit continuity 
malfunctions that cannot be distinguished from malfunctions associated 
with out-of-range values.
    For input components that are used to activate alternative 
strategies that can affect emissions (e.g., AECDs, engine shutdown 
systems), the OBD system would be required to detect rationality 
malfunctions that cause the system to erroneously activate or 
deactivate the alternative strategy. To the extent feasible when using 
all available information, the rationality diagnostics should detect a 
malfunction if the input component inappropriately indicates a value 
that activates or deactivates the alternative strategy. For example, if 
an alternative strategy requires an intake air temperature greater than 
120 degrees Fahrenheit prior to activating, the OBD system should 
detect malfunctions that cause the intake air temperature sensor to 
inappropriately indicate a temperature above 120 degrees Fahrenheit.
    For engines that require precise alignment between the camshaft and 
the crankshaft, the OBD system would be required to monitor the 
crankshaft position sensor(s) and camshaft position sensor(s) to verify 
proper alignment between the camshaft and crankshaft. The OBD system 
would also have to monitor the sensors for circuit continuity and 
rationality malfunctions. Such monitoring for proper alignment between 
a camshaft and a crankshaft would only be required in cases where both 
are equipped with position sensors.
    For engines equipped with VVT systems and a timing belt or chain, 
the OBD system must detect a malfunction if the alignment between the 
camshaft and crankshaft is off by one or more cam/crank sprocket cogs 
(e.g., the timing belt/chain has slipped by one or more teeth/cogs). If 
a manufacturer demonstrates that a single tooth/cog misalignment cannot 
cause a measurable increase in emissions during any reasonable driving 
condition, the OBD system would be required to detect a malfunction 
when the minimum number of teeth/cogs misalignment needed to cause a 
measurable emission increase has occurred.
ii. Output Components/Systems
    We are proposing that the OBD system detect a malfunction of an 
output component/system when proper functional response of the 
component/system to computer commands does not occur. If a functional 
check is not feasible, the OBD system would be required to detect 
malfunctions caused by a lack of circuit continuity (e.g., short to 
ground or high voltage). For output component malfunctions associated 
with the lack of circuit continuity, the OBD system is not required to 
store different DTCs for each distinct malfunction (e.g., open circuit, 
shorted low). Further, manufacturers would not be required to activate 
an output component/system when it would not normally be active for the 
exclusive purpose of performing functional monitoring of output 
components/systems.
    Additionally, the idle control system would have to be monitored 
for proper functional response to computer commands. For gasoline 
engines that use monitoring strategies based on deviation from target 
idle speed, a malfunction would have to be detected when either of the 
following conditions occur: (a) The idle speed control system cannot 
achieve the target idle speed within 200 revolutions per minute (rpm) 
above the target speed or 100 rpm below the target speed--the OBD 
system could use larger engine speed tolerances provided the 
manufacturer is able to demonstrate via data and/or engineering 
analyses that the tolerances can be exceeded without a malfunction 
being present; or, (b) the idle speed control system cannot achieve the 
target idle speed within the smallest engine speed tolerance range 
required by the OBD system to enable any other OBD monitors. For diesel 
engines, a malfunction would have to be detected when either of the 
following conditions occur: (a) The idle fuel control system cannot 
achieve the target idle speed or fuel injection quantity within +/-50 
percent of the manufacturer-specified fuel quantity and engine speed 
tolerances; or, (b) the idle fuel control system cannot achieve the 
target idle speed or fueling quantity within the smallest engine speed 
or fueling quantity tolerance range required by the OBD system to 
enable any other OBD monitors.
    Glow plugs and intake air heater systems would also have to be 
monitored for proper functional response to computer commands and for 
malfunctions associated with circuit continuity. The glow plug and 
intake air heater circuit(s) would have to be monitored for proper 
current and voltage drop. The manufacturer may use other monitoring 
strategies by submitting data and/or engineering analyses that 
demonstrate that the strategy provides equally reliable and timely 
detection of malfunctions. In general, the OBD system would have to 
detect a malfunction when a single glow plug no longer operates within 
the manufacturer's specified limits for normal operation. If a 
manufacturer demonstrates that a single glow plug malfunction cannot 
cause a measurable increase in emissions during any reasonable driving 
condition, the OBD system must detect a malfunction for the minimum 
number of glow plugs needed to cause an emissions increase. Further, to 
the extent feasible without adding additional hardware for this 
purpose, the stored DTC must identify the specific malfunctioning glow 
plug(s).
    Lastly, the wait-to-start lamp circuit and the MIL circuit would 
have to be monitored for malfunctions that cause either lamp to fail to 
illuminate when commanded on (e.g., burned out bulb).
c. Comprehensive Component Monitoring Conditions
i. Input Components
    We are proposing that input components be monitored continuously 
for circuit continuity and for providing values within the proper 
range. For rationality monitoring, where applicable, manufacturers 
would define the monitoring conditions for detecting malfunctions in 
accordance with the general monitoring conditions for all engines 
described in section II.A.3 and the minimum performance ratio 
requirements described in section II.E except that rationality 
monitoring would have to occur every time the monitoring conditions are 
met during the drive cycle rather than once per drive cycle as required 
in section II.A.3.
    A manufacturer may disable continuous monitoring for circuit 
continuity, and for providing values within the proper range, when a

[[Page 3237]]

malfunction cannot be distinguished from other effects. To do so, the 
manufacturer would have to submit data and/or engineering analyses that 
demonstrate that a properly functioning input component cannot be 
distinguished from a malfunctioning input component and that the 
disablement interval is limited only to that necessary for avoiding 
false detection.
ii. Output Components/Systems
    We are proposing that output components/systems be monitored 
continuously for circuit continuity. For functional monitoring, 
manufacturers would define the monitoring conditions for detecting 
malfunctions in accordance with the general monitoring conditions for 
all engines described in section II.A.3 and the minimum performance 
ratio requirements described in section II.E.
    For the idle control system, we are proposing that manufacturers 
define the monitoring conditions for functional monitoring in 
accordance with the general monitoring conditions for all engines 
described in section II.A.3 and the minimum performance ratio 
requirements described in section II.E except that functional 
monitoring would have to occur every time the monitoring conditions are 
met during the drive cycle rather than once per drive cycle as required 
in section II.A.3.
    A manufacturer may disable continuous monitoring for circuit 
continuity when a malfunction cannot be distinguished from other 
effects. To do so, the manufacturer would have to submit data and/or 
engineering analyses that demonstrate that a properly functioning 
output component cannot be distinguished from a malfunctioning output 
component and that the disablement interval is limited only to that 
necessary for avoiding false detection.
d. Comprehensive Component MIL Illumination and DTC Storage
    With a couple of exceptions, we are proposing the general 
requirements for MIL illumination and DTC storage as discussed in 
section II.A.2. The exceptions to this being that MIL illumination 
would not be required in conjunction with storing a MIL-on DTC for any 
comprehensive component if: (a) The component or system, when 
malfunctioning, could not cause engine emissions to increase by 15 
percent or more of the FTP standard during any reasonable driving 
condition; and, (b) the component or system is not used as part of the 
diagnostic strategy for any other monitored system or component. MIL 
illumination is also not required if a malfunction has been detected in 
the MIL circuit that prevents the MIL from illuminating (e.g., burned 
out bulb or light emitting diode (LED)). However, the electronic MIL 
status must be reported as ``commanded on'' and a MIL-on DTC would have 
to be stored.
5. Other Emissions Control System Monitoring
a. Background
    As noted above, the primary purpose of OBD is to detect 
malfunctions in the engine and/or emissions control system. Therefore, 
we are proposing that manufacturers be required to submit to the 
Administrator a monitoring plan for any new engine and/or emissions 
control technology not otherwise described above. Such technology might 
include hydrocarbon traps or homogeneous charge compression ignition 
(HCCI) systems. This would allow manufacturers and EPA to evaluate the 
new technology and determine an appropriate level of monitoring that 
would be both technologically feasible and consistent with the 
monitoring requirements for the other emissions control devices 
described above.
    As proposed, the Administrator would provide guidance as to what 
type of components would fall under the ``other emissions control 
system'' requirements and which would fall under the comprehensive 
component requirements. Specifically, we are concerned that uncertainty 
may arise for those emission control components or systems that also 
meet the definition of electronic engine components. As such, the 
proposal would delineate the two by requiring components/systems that 
fit both definitions but are not corrected or compensated for by the 
adaptive fuel control system to be monitored as ``other emissions 
control devices'' rather than as comprehensive components. A typical 
device that would fall under this category instead of the comprehensive 
components category because of this delineation would be a swirl 
control valve system. Such delineation is necessary because such 
emissions control components generally require more thorough monitoring 
than comprehensive components to ensure low emissions levels throughout 
an engine's life. Further, emissions control components that are not 
compensated for by the fuel control system as they age or deteriorate 
can have a larger impact on tailpipe emissions than is typical of 
comprehensive components that are corrected for by the fuel control 
system as they deteriorate.
    Note that the Administrator does not foresee any outcome where a 
promising new emissions control technology would be prohibited based 
solely on the lack of an OBD monitoring strategy for it. Instead, we 
want to instill in manufacturers the need to consider OBD monitoring 
when developing any new emissions control technology. Further, we want 
to instill in manufacturers the sense that an OBD monitoring strategy 
will, one day, be necessary so a plan for such should exist prior to 
introducing the technology on new products.
b. Other Emissions Control System Monitoring Requirements/Conditions
    We are proposing that, for other emission control systems that are: 
(1) Not identified or addressed in sections II.B through II.D.4--e.g., 
hydrocarbon traps, HCCI control systems; or, (2) identified or 
addressed in section II.D.4 but not corrected or compensated for by an 
adaptive control system--e.g., swirl control valves, manufacturers 
would be required to submit a plan for Administrator approval of the 
monitoring strategy, the malfunction criteria, and the monitoring 
conditions prior to introduction on a production engine. Administrator 
approval of the plan would be based on the effectiveness of the 
monitoring strategy, the robustness of the malfunction criteria, and 
the frequency of meeting the necessary monitoring conditions.
    We are also proposing that, for engines that use emissions control 
systems that alter intake air flow or cylinder charge characteristics 
by actuating valve(s), flap(s), etc., in the intake air delivery system 
(e.g., swirl control valve systems), the manufacturers, in addition to 
meeting the requirements above, may elect to have the OBD system 
monitor the shaft to which all valves in one intake bank are physically 
attached rather than monitoring the intake air flow, cylinder charge, 
or individual valve(s)/flap(s) for proper functional response. For non-
metal shafts or segmented shafts, the monitor must verify all shaft 
segments for proper functional response (e.g., by verifying the segment 
or portion of the shaft furthest from the actuator functions properly). 
For systems that have more than one shaft to operate valves in multiple 
intake banks, manufacturers are not required to add more than one set 
of detection hardware (e.g., sensor, switch) per intake bank to meet 
this requirement.

[[Page 3238]]

6. Exceptions to Monitoring Requirements
a. Background
    Under some conditions, the reliability of specific monitors may be 
diminished significantly. Therefore, we are proposing to allow 
manufacturers to disable the affected monitors when these conditions 
are encountered in-use. These include situations of extreme conditions 
(e.g., very low ambient temperatures, high altitudes) and of periods 
where default modes of operation are active (e.g., when a tire pressure 
problem is detected). In some of these cases, we may allow 
manufacturers to revise the emission malfunction threshold to ensure 
the most reliable monitoring performance.
b. Requirements for Exceptions to Monitoring
    The Administrator may revise the emission threshold for any 
monitor, or revise the PM filtering performance malfunction criteria 
for DPFs to exclude detection of specific failure modes such as 
partially melted substrates, if the most reliable monitoring method 
developed requires a higher threshold or, in the case of PM filtering 
performance, the exclusion of specific failure modes, to prevent 
significant errors of commission in detecting a malfunction. The 
Administrator would notify the industry of any such revisions to ensure 
that all manufacturers would be able to implement OBD on an equal 
basis. In other words, we would not allow one manufacturer to revise a 
specific monitoring threshold upwards while insisting that another meet 
the proposed threshold.
    Manufacturers may disable an OBD system monitor at ambient engine 
start temperatures below 20 degrees Fahrenheit (low ambient temperature 
conditions may be determined based on intake air or engine coolant 
temperature at engine start) or at elevations higher than 8000 feet 
above sea level. To do so, the manufacturer would have to submit data 
and/or engineering analyses that demonstrate that monitoring would be 
unreliable during the disable conditions. A manufacturer may request 
that an OBD system monitor be disabled at other ambient engine start 
temperatures by submitting data and/or engineering analyses 
demonstrating that misdiagnosis would occur at the given ambient 
temperatures due to their effect on the component itself (e.g., 
component freezing).
    Manufacturers may disable an OBD system monitor when the fuel level 
is 15 percent or less of the nominal fuel tank capacity for those 
monitors that can be affected by low fuel level or running out of fuel 
(e.g., misfire detection). To do so, the manufacturer would have to 
submit data and/or engineering analyses that demonstrate that both 
monitoring at the given fuel levels would be unreliable, and the OBD 
system is still able to detect a malfunction if the component(s) used 
to determine fuel level indicates erroneously a fuel level that causes 
the disablement.
    Manufacturers may disable OBD monitors that can be affected by 
vehicle battery or system voltage levels. For an OBD monitor affected 
by low vehicle battery or system voltages, manufacturers may disable 
monitoring when the battery or system voltage is below 11.0 Volts. 
Manufacturers may use a voltage threshold higher than 11.0 Volts to 
disable monitors but would have to submit data and/or engineering 
analyses that demonstrate that monitoring at those voltages would be 
unreliable and that either operation of a vehicle below the disablement 
criteria for extended periods of time is unlikely or the OBD system 
monitors the battery or system voltage and would detect a malfunction 
at the voltage used to disable other monitors.
    For monitoring systems affected by high vehicle battery or system 
voltages, manufacturers may disable monitoring when the battery or 
system voltage exceeds a manufacturer-defined voltage. To do so, the 
manufacturer would have to submit data and/or engineering analyses that 
demonstrate that monitoring above the manufacturer-defined voltage 
would be unreliable and that either the electrical charging system/
alternator warning light would be illuminated (or voltage gauge would 
be in the ``red zone'') or the OBD system monitors the battery or 
system voltage and would detect a malfunction at the voltage used to 
disable other monitors.
    A manufacturer may also disable affected OBD monitors in vehicles 
designed to accommodate the installation of power take off (PTO) units 
provided disablement occurs only while the PTO unit is active and the 
OBD readiness status is cleared by the onboard computer (i.e., all 
monitors set to indicate ``not complete'') while the PTO unit is 
activated (see section II.F.4 below). If the disablement occurs, the 
readiness status may be restored, when the disablement ends, to its 
state prior to PTO activation.

E. A Standardized Method To Measure Real World Monitoring Performance

    As was noted in section II.A.3, manufacturers determine the most 
appropriate times to run the non-continuous OBD monitors. This way, 
they are able to make their OBD evaluation either at the operating 
condition when an emissions control system is active and its 
operational status can best be evaluated, and/or at the operating 
condition when the most accurate evaluation can be made (e.g., highly 
transient conditions or extreme conditions can make evaluation 
difficult). Importantly, manufacturers are prohibited from using a 
monitoring strategy that is so restrictive such that it rarely or never 
runs. To help protect against monitors that rarely run, we are 
proposing an ``in-use monitor performance ratio'' requirement as 
described here.
    The set of operating conditions that must be met so that an OBD 
monitor can run are called the ``enable criteria'' for that given 
monitor. These enable criteria are often different for different 
monitors and may well be different for different types of engines. A 
large diesel engine intended for use in a Class 8 truck would be 
expected to see long periods of relatively steady-state operation while 
a smaller engine intended for use in an urban delivery truck would be 
expected to see a lot of transient operation. Manufacturers will need 
to balance between a rather loose set of enable criteria for their 
engines and vehicles given the very broad range of operation HD highway 
engines see and a tight set of enable criteria given the desire for 
greater monitor accuracy. Manufacturers would be required to design 
these enable criteria so that the monitor:
     Is robust (i.e., accurate at making pass/fail decisions);
     Runs frequently in the real world; and,
     In general, also runs during the FTP heavy-duty transient 
cycle.
    If designed incorrectly, these enable criteria may be either too 
broad and result in inaccurate monitors, or overly restrictive thereby 
preventing the monitor from executing frequently in the real world.
    Since the primary purpose of an OBD system is to monitor for and 
detect emission-related malfunctions while the engine is operating in 
the real world, a standardized methodology for quantifying real world 
performance would be beneficial to both EPA and manufacturers. 
Generally, in determining whether a manufacturer's monitoring 
conditions are sufficient, a manufacturer would discuss the proposed 
monitoring conditions with EPA staff. The finalized conditions would be 
included in the certification applications and submitted to EPA staff 
who would review the conditions and make determinations on a case-by-
case

[[Page 3239]]

basis based on the engineering judgment of the staff. In cases where we 
are concerned that the documented conditions may not be met during 
reasonable in-use driving conditions, we would most likely ask the 
manufacturer for data or other engineering analyses used by the 
manufacturer to determine that the conditions would occur in-use. In 
proposing a standardized methodology for quantifying real world 
performance, we believe this review process can be done more 
efficiently than would occur otherwise. Furthermore, it would serve to 
ensure that all manufacturers are held to the same standard for real 
world performance. Lastly, we want review procedures that will ensure 
that monitors operate properly and frequently in the field.
    Therefore, we are proposing that all manufacturers be required to 
use a standardized method for determining real world monitoring 
performance and to hold manufacturers liable if monitoring occurs less 
frequently than a minimum acceptable level, expressed as minimum 
acceptable in-use performance ratio. We are also proposing that 
manufacturers be required to implement software in the onboard computer 
to track how often several of the major monitors (e.g., catalyst, EGR, 
CDPF, other diesel aftertreatment devices) execute during real world 
driving. The onboard computer would keep track of how many times each 
of these monitors has executed and how much the engine has been 
operated. By measuring both of these values, the ratio of monitor 
operation relative to engine operation can be calculated to determine 
monitoring frequency.
    The proposed minimum acceptable frequency requirement would apply 
to many but not all of the OBD monitors. We are proposing that monitors 
be required to operate either continuously, once per drive cycle, or, 
in a few cases, multiple times per drive cycle (i.e., whenever the 
proper monitoring conditions are present). For components or systems 
that are more likely to experience intermittent failures or failures 
that can routinely happen in distinct portions of an engine's operating 
range (e.g., only at high engine speed and load, only when the engine 
is cold or hot), monitors would be required to operate continuously. 
Examples of continuous monitors include the fuel system monitor and 
most electrical/circuit continuity monitors. For components or systems 
that are less likely to experience intermittent failures or failures 
that only occur in specific vehicle operating regions or for components 
or systems where accurate monitoring can only be performed under 
limited operating conditions, monitors would be required to run once 
per drive cycle. Examples of once per drive cycle monitors typically 
include gasoline catalyst monitors, evaporative system leak detection 
monitors, and output comprehensive component functional monitors. For 
components or systems that are routinely used to perform functions that 
are crucial to maintaining low emissions but may still require 
monitoring under fairly limited conditions, monitors would be required 
to run each and every time the manufacturer-defined enable conditions 
are present. Examples of multiple times per drive cycle monitors 
typically include input comprehensive component rationality monitors 
and some exhaust aftertreatment monitors.
    Monitors required to run continuously, by definition, would always 
be running, thereby making a minimum frequency requirement moot. The 
new frequency requirement would essentially apply only to those 
monitors that are designated as once per drive cycle or multiple times 
per drive cycle monitors. For all of these monitors, manufacturers 
would be required to define monitoring conditions that ensure adequate 
frequency in-use. Specifically, the monitors would need to run often 
enough so that the measured monitor frequency on in-use engines would 
exceed the minimum acceptable frequency. However, even though the 
minimum frequency requirement would apply to nearly all once per drive 
cycle and multiple times per drive cycle monitors, manufacturers would 
only be required to implement software to track and report the in-use 
frequency for a few of the major monitors. These few monitors generally 
represent the major emissions control components and the ones with the 
most limited enable criteria.
    We believe that OBD monitors should run frequently to ensure early 
detection of emissions-related malfunctions and, consequently, to 
maintain low emissions. Allowing malfunctions to continue undetected 
and unrepaired for long periods of time allows emissions to increase 
unnecessarily. Frequent monitoring can also help to ensure detection of 
intermittent emissions-related malfunctions (i.e., those that are not 
continuously present but occur sporadically for days and even weeks at 
a time). The nature of mechanical and electrical systems is that 
intermittent malfunctions can and do occur. The less frequent the 
monitoring, the less likely these malfunctions will be detected and 
repaired. Additionally, for both intermittent and continuous 
malfunctions, earlier detection is equivalent to preventative 
maintenance in that the original malfunction can be detected and 
repaired prior to it causing subsequent damage to other components. 
This can help vehicle operators avoid more costly repairs that could 
have resulted had the first malfunction gone undetected.
    Infrequent monitoring can also have an impact on the service and 
repair industry. Specifically, monitors that have unreasonable or 
overly restrictive enable conditions could hinder vehicle repair 
services. In general, upon completing an OBD-related repair to an 
engine, a technician will attempt to verify that the repair has indeed 
fixed the problem. Ideally, a technician will operate the vehicle in a 
manner that will exercise the appropriate OBD monitor and allow the OBD 
system to confirm that the malfunction is no longer present. This 
affords a technician the highest level of assurance that the repair was 
indeed successful. However, OBD monitors that operate infrequently are 
difficult to exercise and, therefore, technicians may not be able (or 
may not be likely) to perform such post-repair evaluations. Despite the 
service information availability requirements we are proposing--
requirements that manufacturers make all of their service and repair 
information available to all technicians, including the information 
necessary to exercise OBD monitors--technicians would still find it 
difficult to exercise monitors that require infrequently encountered 
engine operating conditions (e.g., abnormally steady constant speed 
operation for an extended period of time). Additionally, to execute OBD 
monitors in an expeditious manner or to execute monitors that would 
require unusual or infrequently encountered conditions, technicians may 
be required to operate the vehicle in an unsafe manner (e.g., at 
freeway speeds on residential streets or during heavy traffic). If 
unsuccessful in executing these monitors, technicians may even take 
shortcuts in attempting to validate the repair while maintaining a 
reasonable cost for customers. These shortcuts would likely not be as 
thorough in verifying repairs and could increase the chance that 
improperly repaired engines would be returned to the vehicle owner or 
additional repairs would be performed just to ensure the problem is 
fixed. In the end, monitors that operate less frequently can result in 
unnecessary costs and inconvenience to both vehicle owners and 
technicians.

[[Page 3240]]

1. Description of Software Counters to Track Real World Performance
    As stated above, manufacturers would be required to track monitor 
peformance by comparing the number of monitoring events (i.e., how 
often each monitor has run) to the number of driving events (i.e., how 
often has the vehicle been operated). The ratio of these two numbers 
would give an indication of how often the monitor is operating relative 
to vehicle operation. In equation form, this can be stated as:
[GRAPHIC] [TIFF OMITTED] TP24JA07.004

    To ensure that all manufacturers are tracking in-use performance in 
the same manner, we are proposing very detailed requirements for 
defining and incrementing both the numerator and denominator of this 
ratio. Manufacturers would be required to keep track of separate 
numerators and denominators for each of the major monitors, and to 
ensure that the data are saved every time the engine is shut off. The 
numerators and denominators would be reset to zero only in extreme 
circumstances when the non-volatile memory has been cleared (e.g., when 
the onboard computer has been reprogrammed in the field or when the 
onboard computer memory has been corrupted). The values would not be 
reset to zero during normal occurrences such as clearing of stored DTCs 
or performing routine service or maintenance.
    Further, the numerator and denominator would be structured such 
that their maximum values would be 65,535 which is the maximum number 
that can be stored in a 2-byte location. This would ensure that 
manufacturers allocate sufficient and consistent memory space in the 
onboard computer. If either the numerator or denominator for a 
particular monitor reaches the maximum value, both values for that 
particular monitor would be divided by two before counting resumes. In 
general, the numerator and denominator would only be allowed to 
increment a maximum of once per drive cycle because most of the major 
monitors are designed to operate only once per drive cycle. 
Additionally, incrementing of both the numerator and denominator for a 
particular monitor would be disabled (i.e., paused but the stored 
values would not be erased or reset) only when a problem has been 
detected (i.e., a pending or MIL-on DTC has been stored) that prevents 
the monitor from executing. Once the problem is no longer detected and 
any stored DTCs associated with the problem have been erased, either 
through the allowable self-clearing process or upon command by a 
technician via a scan tool, incrementing of both the numerator and 
denominator would resume.
    SAE has developed standards for storing and reporting the data to a 
generic scan tool. This would help ensure that all manufacturers report 
the data in an identical manner which should ease data collection in 
the field.
a. Number of Monitoring Events (``Numerator'')
    For the numerator, manufacturers would be required to keep a 
separate numeric count of how often each of the particular monitors has 
operated. More specifically, manufacturers would have to implement a 
software counter that increments by one every time the particular 
monitor meets all of the enable/monitoring conditions for a long enough 
period of time such that a malfunctioning component would have been 
detected. For example, if a manufacturer requires a vehicle to be 
warmed-up and at idle for 20 seconds continuously to detect a 
malfunctioning catalyst, the catalyst monitor numerator could only be 
incremented if the vehicle actually operates simultaneously in all of 
those conditions. If the vehicle is operated in some but not all of the 
conditions (e.g., at idle but not warmed-up), the numerator would not 
be allowed to increment because the monitor would not have been able to 
detect a malfunctioning catalyst since all of the conditions were not 
satisfied simultaneously.
    Another complication is the difference between a monitor reaching a 
``pass'' or ``fail'' decision. At first glance, it would appear that a 
manufacturer should simply increment the numerator anytime the 
particular monitor reaches a decision, be it ``pass'' or ``fail''. 
However, monitoring strategies may have a different set of criteria 
that must be met to reach a ``pass'' decision versus a ``fail'' 
decision. As a simple example, a manufacturer may appropriately require 
only 10 seconds of operation at idle to reach a ``pass'' decision but 
require 30 seconds of operation at idle to reach a ``fail'' decision. 
Manufacturers would not be allowed to increment the numerator if the 
vehicle had idled for 10 seconds and reached a ``pass'' decision since 
insufficient time had passed to allow for a possible ``fail'' decision. 
This is necessary because the primary function of OBD systems is to 
detect malfunctions (i.e., to correctly reach ``fail'' decisions, not 
``pass'' decisions) and, thus, the real world ability of the monitors 
to detect malfunctions is the parameter we want most to measure. 
Therefore, monitors with different criteria to reach a ``pass'' 
decision versus a ``fail'' decision would not be allowed to increment 
the numerator solely upon satisfying the ``pass'' criteria.
    The correct implementation of the numerator counters by 
manufacturers is imperative to ensure a reliable measure for 
determining real world performance. ``Overcounting'' would falsely 
indicate the monitor is executing more often than it really is, while 
``undercounting'' would make it appear as if the monitor is not running 
as often as it really is. Manufacturers would be required to describe 
their numerator incrementing strategy in their certification 
documentation and to verify the proper performance of their strategy 
during production vehicle evaluation testing.
b. Number of Driving Events (``Denominator'')
    We are also proposing that manufacturers separately track how often 
the engine is operated. Basically, the denominator would be a counter 
that increments by one each time the engine is operated. We are 
proposing that the denominator counter be incremented by one only if 
several criteria are satisfied during a single drive cycle. This allows 
very short trips or trips during extreme conditions such as very cold 
temperatures or very high altitude to be filtered out and excluded from 
the count. This is appropriate because these are also conditions where 
most OBD monitors are neither expected nor required to operate.
    Specifically, the denominator would be incremented if, on a single 
key start, the following criteria were satisfied while ambient 
temperature remained above 20 degrees Fahrenheit and altitude remained 
below 8,000 feet:
     Minimum engine run time of 10 minutes;

[[Page 3241]]

     Minimum of 5 minutes, cumulatively, of operation at 
vehicle speeds greater than 25 miles-per-hour for gasoline engines or 
calculated load greater than 15 percent for diesel engines; and
     At least one continuous idle for a minimum of 30 seconds 
encountered.
    We intend to work with industry to collect data during the first 
few years of implementation and make any adjustments, if necessary, to 
the criteria used to increment the denominator to ensure that the in-
use performance ratio provides a meaningful measure of in-use 
monitoring performance.
2. Proposed Performance Tracking Requirements
a. In-use Monitoring Performance Ratio Definition
    For monitors required to meet the in-use performance tracking 
requirements,\44\ we are proposing that the incrementing of numerators 
and denominators and the calculation of the in-use performance ratio be 
done in accordance with the following specifications.
---------------------------------------------------------------------------

    \44\ These monitors, as presented in section II.A.3, are, for 
diesel engines: the NMHC catalyst, the CDPF system, the 
NOX adsorber system, the NOX converting 
catalyst system, and the boost system; and, for gasoline engines: 
the catalyst, the evaporative system, and the secondary air system; 
and, for all engines, the exhaust gas sensors, the EGR system, and 
the VVT system.
---------------------------------------------------------------------------

    The numerator(s) would be defined as a measure of the number of 
times a vehicle has been operated such that all monitoring conditions 
necessary for a specific monitor to detect a malfunction have been 
encountered. Except for systems using alternative statistical MIL 
illumination protocols, the numerator is to be incremented by an 
integer of one. The numerator(s) may not be incremented more than once 
per drive cycle. The numerator(s) for a specific monitor would be 
incremented within 10 seconds if and only if the following criteria are 
satisfied on a single drive cycle:
     Every monitoring condition necessary for the monitor of 
the specific component to detect a malfunction and store a pending DTC 
has been satisfied, including enable criteria, presence or absence of 
related DTCs, sufficient length of monitoring time, and diagnostic 
executive priority assignments (e.g., diagnostic ``A'' must execute 
prior to diagnostic ``B''). For the purpose of incrementing the 
numerator, satisfying all the monitoring conditions necessary for a 
monitor to determine that the component is passing may not, by itself, 
be sufficient to meet this criteria.
     For monitors that require multiple stages or events in a 
single drive cycle to detect a malfunction, every monitoring condition 
necessary for all events to have completed must be satisfied.
     For monitors that require intrusive operation of 
components to detect a malfunction, a manufacturer would be required to 
request Administrator approval of the strategy used to determine that, 
had a malfunction been present, the monitor would have detected the 
malfunction. Administrator approval of the request would be based on 
the equivalence of the strategy to actual intrusive operation and the 
ability of the strategy to determine accurately if every monitoring 
condition was satisfied as necessary for the intrusive event to occur.
     For the secondary air system monitor, the three criteria 
above are satisfied during normal operation of the secondary air 
system. Monitoring during intrusive operation of the secondary air 
system later in the same drive cycle solely for the purpose of 
monitoring may not, by itself, be sufficient to meet these criteria.
    The third bullet item above requires explanation. There may be 
monitors, and there have been monitors in light-duty, designed to use 
what could be termed a two stage or two step process. The first step is 
usually a passive and/or short evaluation that can be used to ``pass'' 
a properly working component where ``pass'' refers to evaluating the 
component and determining that it is not malfunctioning. The second 
step is usually an intrusive and/or longer evaluation that is necessary 
to ``fail'' a malfunctioning component or ``pass'' a component nearing 
the point of failure. An example of such an approach might be an 
evaporative leak detection monitor that uses an intrusive vacuum pull-
down/bleed-up evaluation during highway cruise conditions. If the 
evaporative system is sealed tight, the monitor ``passes'' and is done 
with testing for the given drive cycle. If the monitor senses a leak 
close to the required detection limit, the monitor does not ``pass'' 
and an internal flag is stored that will trigger the second stage of 
the test during the next cold start when a more accurate evaluation can 
be conducted. On the next cold start, provided the internal flag is 
set, an intrusive vacuum pull-down/bleed up monitor might be conducted 
during engine idle a very short time after the cold start. This second 
evaluation stage, being at idle and cold, gives a more accurate 
indication of the evaporative system's integrity and provides for a 
more accurate decision regarding the presence and size of a leak.
    In this example, the second stage of this monitor would run less 
frequently in real use than the first stage since it is activated only 
on those occasions where the first stage suggests that a leak may be 
present (which most cars will not have). The rate-based tracking 
requirements are meant to give a measure of how often a monitor could 
detect a malfunction. To know the right answer, we need to know how 
often the first stage is running and could ``fail'', thus triggering 
the second stage, and then how often the second stage is completing. If 
we track only the first stage, we would get a false indication of how 
often the monitor could really detect a leak. But, if we track only the 
second stage, most cars would never increment the counter since most 
cars do not have leaks and would not trigger stage two.
    In considering this, we see two possible solutions: (1) Always 
activate the second stage evaluation in which case there would be an 
intrusive monitor being performed that does not really need to be 
performed; or, (2) implement a ``ghost'' monitor that pretends that the 
first stage evaluation triggers the second stage evaluation and then 
also looks for when the second stage evaluation could have completed 
had it been necessary. The third bullet item in the list above requires 
that, if a manufacturer intends to implement a two stage monitor and 
intends to implement such a ``ghost'' monitor as described here for 
rate based tracking, approval must be sought for doing so to make sure 
we agree that you are doing it correctly and properly.
    For monitors that can generate results in a ``gray zone'' or ``non-
detection zone'' (i.e., results that indicate neither a passing system 
nor a malfunctioning system) or in a ``non-decision zone'' (e.g., 
monitors that increment and decrement counters until a pass or fail 
threshold is reached), the manufacturer would be responsible for 
incrementing the numerator appropriately. In general, the numerator 
should not be incremented when the monitor indicates a result in the 
``non-detection zone'' or prior to the monitor reaching a decision. 
When necessary, the Administrator would consider data and/or 
engineering analyses submitted by the manufacturer demonstrating the 
expected frequency of results in the ``non-detection zone'' and the 
ability of the monitor to determine accurately, had an actual 
malfunction been present, whether or not the monitor would have 
detected a malfunction instead of a result in the ``non-detection 
zone.''

[[Page 3242]]

    For monitors that run or complete their evaluation with the engine 
off, the numerator must be incremented either within 10 seconds of the 
monitor completing its evaluation in the engine off state, or during 
the first 10 seconds of engine start on the subsequent drive cycle.
    Manufacturers using alternative statistical MIL illumination 
protocols for any of the monitors that require a numerator would be 
required to increment the numerator(s) appropriately. The manufacturer 
may be required to provide supporting data and/or engineering analyses 
demonstrating both the equivalence of their incrementing approach to 
the incrementing specified above for monitors using the standard MIL 
illumination protocol, and the overall equivalence of their 
incrementing approach in determining that the minimum acceptable in-use 
performance ratio has been satisfied.
    Regarding the denominator(s), defined as a measure of the number of 
times a vehicle has been operated, we are proposing that it also be 
incremented by an integer of one. The denominator(s) may not be 
incremented more than once per drive cycle. The general denominator and 
the denominators for each monitor would be incremented within 10 
seconds if and only if the following criteria are satisfied on a single 
drive cycle during which ambient temperature remained at or above 20 
degrees Fahrenheit and altitude remained below 8,000 feet:
     Cumulative time since the start of the drive cycle is 
greater than or equal to 600 seconds (10 minutes);
     Cumulative gasoline engine operation at or above 25 miles 
per hour or diesel engine operation at or above 15 percent calculated 
load, either of which occurs for greater than or equal to 300 seconds 
(5 minutes); and
     Continuous engine operation at idle (e.g., accelerator 
pedal released by driver and vehicle speed less than or equal to one 
mile per hour) for greater than or equal to 30 seconds.
    In addition to the requirements above, the evaporative system 
monitor denominator(s) must be incremented if and only if:
     Cumulative time since the start of the drive cycle is 
greater than or equal to 600 seconds (10 minutes) while at an ambient 
temperature of greater than or equal to 40 degrees Fahrenheit but less 
than or equal to 95 degrees Fahrenheit; and
     Engine cold start occurs with engine coolant temperature 
at engine start greater than or equal to 40 degrees Fahrenheit but less 
than or equal to 95 degrees Fahrenheit and less than or equal to 12 
degrees Fahrenheit higher than ambient temperature at engine start.
    In addition to the requirements above, the denominator(s) for the 
following monitors must be incremented if and only if the component or 
strategy is commanded ``on'' for a time greater than or equal to 10 
seconds:
     Gasoline secondary air system;
     Cold start emission reduction strategy;
     Components or systems that operate only at engine start-up 
(e.g., glow plugs, intake air heaters) and are subject to monitoring 
under ``other emission control systems'' (section II.D.5) or 
comprehensive component output components (see section II.D.4).
    For purposes of determining this commanded ``on'' time, the OBD 
system may not include time during intrusive operation of any of the 
components or strategies later in the same drive cycle solely for the 
purposes of monitoring.
    In addition to the requirements above, the denominator(s) for the 
monitors of the following output components (except those operated only 
at engine start-up as outlined above) must be incremented if and only 
if the component is commanded to function (e.g., commanded ``on'', 
``open'', ``closed'', ``locked'') two or more times during the drive 
cycle or for a time greater than or equal to 10 seconds, whichever 
occurs first:
     Variable valve timing and/or control system
     ``Other emission control systems''
     Comprehensive component (output component only, e.g., 
turbocharger waste-gates, variable length manifold runners)
    For monitors of the following components, the manufacturer may use 
alternative or additional criteria to that set forth above for 
incrementing the denominator. To do so, the manufacturer would need to 
be able to demonstrate that the criteria would be equivalent to the 
criteria outlined above at measuring the frequency of monitor operation 
relative to the amount of engine operation:
     Engine cooling system input components (section II.D.2)
     ``Other emission control systems'' (section II.D.5)
     Comprehensive component input components that require 
extended monitoring evaluation (section II.D.4, e.g., stuck fuel level 
sensor rationality)
    For monitors of the following components or other emission controls 
that experience infrequent regeneration events, the manufacturer may 
use alternative or additional criteria to that set forth above for 
incrementing the denominator. To do so, the manufacturer would need to 
demonstrate that the criteria would be equivalent to the criteria 
outlined above at measuring the frequency of monitor operation relative 
to the amount of engine operation:
     Oxidation catalysts
     Diesel particulate filters
    For hybrid engine systems, engines that employ alternative engine 
start hardware or strategies (e.g., integrated starter and generators), 
or alternative fueled engines (e.g., dedicated, bi-fuel, or dual-fuel 
applications), the manufacturer may request Administrator approval to 
use alternative criteria to that set forth above for incrementing the 
denominator. In general, approval would not be given for alternative 
criteria that only employ engine shut off at or near idle/vehicle 
stationary conditions. Approval of the alternative criteria would be 
based on the equivalence of the alternative criteria at determining the 
amount of engine operation relative to the measure of conventional 
engine operation in accordance with the criteria above.
    The numerators and denominators may need to be disabled at some 
times. To do this, within 10 seconds of a malfunction being detected 
(i.e., a pending, MIL-on, or active DTC being stored) that disables a 
monitor required to meet the performance tracking requirements,\45\ the 
OBD system must disable further incrementing of the corresponding 
numerator and denominator for each monitor that is disabled. When the 
malfunction is no longer detected (e.g., the pending DTC is erased 
through self-clearing or through a scan tool command), incrementing of 
all corresponding numerators and denominators should resume within 10 
seconds. Also, within 10 seconds of the start of a power takeoff unit 
(PTO) that disables a monitor required to meet the performance tracking 
requirements, the OBD system should disable further incrementing of the 
corresponding numerator and denominator for each monitor that is 
disabled. When the PTO operation ends, incrementing of all 
corresponding numerators and denominators should resume within 10 
seconds. The OBD system must disable further incrementing of all 
numerators

[[Page 3243]]

and denominators within 10 seconds if a malfunction has been detected 
in any component used to determine if: vehicle speed/calculated load; 
ambient temperature; elevation; idle operation; engine cold start; or, 
time of operation has been satisfied, and the corresponding pending DTC 
has been stored. Incrementing of all numerators and denominators should 
resume within 10 seconds when the malfunction is no longer present 
(e.g., pending DTC erased through self-clearing or by a scan tool 
command).
---------------------------------------------------------------------------

    \45\ These monitors, as presented in section II.A.3, are, for 
diesel engines: the NMHC catalyst, the CDPF system, the 
NOX adsorber system, the NOX converting 
catalyst system, and the boost system; and, for gasoline engines: 
the catalyst, the evaporative system, and the secondary air system; 
and, for all engines, the exhaust gas sensors, the EGR system, and 
the VVT system.
---------------------------------------------------------------------------

    The in-use performance monitoring ratio itself is defined as the 
numerator for the given monitor divided by the denominator for that 
monitor.
b. Standardized Tracking and Reporting of Monitor Performance
    We are proposing that the OBD system separately report an in-use 
monitor performance numerator and denominator for each of the following 
components:
     For diesel engines: NMHC catalyst bank 1, NMHC catalyst 
bank 2, NOX catalyst bank 1, NOX catalyst bank 2, 
exhaust gas sensor bank 1, exhaust gas sensor bank 2, EGR/VVT system, 
DPF system, turbo boost control system, and the NOX 
adsorber. The OBD system must also report a general denominator and an 
ignition cycle counter in the standardized format discussed below and 
in section II.F.5.
     For gasoline engines: catalyst bank 1, catalyst bank 2, 
oxygen sensor bank 1, oxygen sensor bank 2, evaporative leak detection 
system, EGR/VVT system, and secondary air system. The OBD system must 
also report a general denominator and an ignition cycle counter in the 
standardized format specified below and in section II.F.5.
    The OBD system would be required to report a separate numerator for 
each of the components listed in the above bullet lists. For specific 
components or systems that have multiple monitors that are required to 
be reported under section II.B--e.g., exhaust gas sensor bank 1 may 
have multiple monitors for sensor response or other sensor 
characteristics--the OBD system should separately track numerators and 
denominators for each of the specific monitors and report only the 
corresponding numerator and denominator for the specific monitor that 
has the lowest numerical ratio. If two or more specific monitors have 
identical ratios, the corresponding numerator and denominator for the 
specific monitor that has the highest denominator should be reported 
for the specific component. The numerator(s) must be reported in 
accordance with the specifications in section II.F.5.
    The OBD system would also be required to report a separate 
denominator for each of the components listed in the above bullet 
lists. The denominator(s) must be reported in accordance with the 
specifications in section II.F.5.
    Similarly, for the in-use performance ratio, determining which 
corresponding numerator and denominator to report as required for 
specific components or systems that have multiple monitors that are 
required to be reported--e.g., exhaust gas sensor bank 1 may have 
multiple monitors for sensor response or other sensor 
characteristics'the ratio should be calculated in accordance with the 
specifications in section II.F.5.
    The ignition cycle counter is defined as a counter that indicates 
the number of ignition cycles a vehicle has experienced. The ignition 
cycle counter must also be reported in accordance with the 
specifications in section II.F.5. The ignition cycle counter, when 
incremented, should be incremented by an integer of one. The ignition 
cycle counter may not be incremented more than once per ignition cycle. 
The ignition cycle counter should be incremented within 10 seconds if 
and only if the engine exceeds an engine speed of 50 to 150 rpm below 
the normal, warmed-up idle speed (as determined in the drive position 
for vehicles equipped with an automatic transmission) for at least two 
seconds plus or minus one second. The OBD system should disable further 
incrementing of the ignition cycle counter within 10 seconds if a 
malfunction has been detected in any component used to determine if 
engine speed or time of operation has been satisfied and the 
corresponding pending DTC has been stored. The ignition cycle counter 
may not be disabled from incrementing for any other condition. 
Incrementing of the ignition cycle counter should resume within 10 
seconds after the malfunction is no longer present (e.g., pending DTC 
erased through self-clearing or by a scan tool command).

F. Standardization Requirements

    The heavy-duty OBD regulation would include requirements for 
manufacturers to standardize certain features of the OBD system. 
Effective standardization assists all repair technicians in diagnosing 
and repairing malfunctions by providing equal access to essential 
repair information, and requires structuring the information in a 
common format from manufacturer to manufacturer. Additionally, the 
standardization would help to facilitate the potential use of OBD 
checks in heavy-duty inspection and maintenance programs.
    Among the features that would be standardized under the proposed 
heavy-duty OBD regulation include:
     The diagnostic connector, the computer communication 
protocol;
     The hardware and software specifications for tools used by 
service technicians;
     The information communicated by the onboard computer and 
the methods for accessing that information;
     The numeric designation of the DTCs stored when a 
malfunction is detected; and,
     The terminology used by manufacturers in their service 
manuals.
    Our proposal would require that only a certain minimum set of 
emissions-related information be made available through the 
standardized format, protocol, and connector. We are not limiting 
engine manufacturers as to what protocol they use for engine control, 
communication between onboard computers, or communication to 
manufacturer-specific scan tools or test equipment. Further, we are not 
prohibiting engine manufacturers from equipping the vehicle with 
additional diagnostic connectors or protocols as required by other 
suppliers or purchasers. For example, fleets that use data logging or 
other equipment that requires the use of SAE J1587 communication and 
connectors could still be installed and supported by the engine and 
vehicle manufacturers. The OBD rules would only require that engine 
manufacturers also equip their vehicles with a specific connector and 
communication protocol that meet the standardized requirements to 
communicate a minimum set of emissions-related diagnostic, service and, 
potentially, inspection information.
    Additionally, our proposal includes a phase-in of one engine family 
meeting the requirements of OBD in the model years 2010 through 2012. 
Because non-compliant engines would not require the proposed 
standardization features, truck and coach builders could be faced with 
several integration issues when building product in 2010 through 2012. 
Specifically, they could be faced with designing their vehicles to 
accommodate a standardized MIL, diagnostic connector, and communication 
protocol when using a compliant engine yet to not accommodate those 
features when using a non-compliant engine. This outcome could easily 
arise since only one engine-family per manufacturer would be compliant 
and, therefore, a given truck

[[Page 3244]]

designed to accommodate several engines from several engine 
manufacturers would very likely need to accommodate a compliant engine 
from manufacturer A and a non-compliant engine from manufacturer B. It 
should be noted that engine choices are typically driven by the end 
user--the truck buyer--and not by the truck or coach builder. For that 
reason, the truck builder must accommodate all possible engines for the 
truck size and cannot necessarily demand from the engine manufacturer a 
compliant versus a non-compliant engine.
    As a result, rather than force truck and coach builders to 
accommodate two different systems and risk incompatibilities, we are 
proposing to exempt the 2010 through 2012 model year engines from 
meeting certain standardization requirements of OBD. This should allow 
truck and coach builders to integrate engines in the same manner as 
done currently and then to switch over to integrating a single system 
in 2013 when all engines are required to meet all of the 
standardization requirements of OBD. The proposed implementation 
schedule for standardization features is shown in Table II.G-2.
1. Reference Documents
    We are proposing that OBD systems comply with the following 
provisions laid out in the following Society of Automotive Engineers 
(SAE) and/or International Organization of Standards (ISO) documents 
that are or would be incorporated by reference (IBR) into federal 
regulation:

                          Table II.F--1. Reference Documents for Over 14,000 Pound OBD
----------------------------------------------------------------------------------------------------------------
       Document No.                    Document title                    Date                   Comment
----------------------------------------------------------------------------------------------------------------
SAE J1962.................  ``Diagnostic Connector--Equivalent   April 2002..........  Updated IBR.
                             to ISO/DIS 15031-3: December 14,
                             2001''.
SAE J1930.................  ``Electrical/Electronic Systems      April 2002..........  Updated IBR.
                             Diagnostic Terms, Definitions,
                             Abbreviations, and Acronyms--
                             Equivalent to ISO/TR 15031-2:
                             April 30, 2002''.
SAE J1978.................  ``OBD II Scan Tool--Equivalent to    April 2002..........  Updated IBR.
                             ISO/DIS 15031-4: December 14,
                             2001''.
SAE J1979.................  ``E/E Diagnostic Test Modes--        April 2002..........   Updated IBR.
                             Equivalent to ISO/DIS 15031-5:
                             April 30, 2002''.
SAE J2012.................  ``Diagnostic Trouble Code            April 2002..........  Updated IBR.
                             Definitions--Equivalent to ISO/DIS
                             15031-6: April 30, 2002''.
SAE J1939.................  ``Recommended Practice for a Serial  2005 Edition, March   Updated IBR.
                             Control and Communications Vehicle   2005.
                             Network,'' and the associated
                             subparts included in SAE HS-1939,
                             ``Truck and Bus Control and
                             Communications Network Standards
                             Manual''.
SAE J2403.................  ``Medium/Heavy-Duty E/E Systems      August 2004.........  New IBR.
                             Diagnosis Nomenclature''.
SAE J2534.................  ``Recommended Practice for Pass-     February 2002.......  New IBR.
                             Thru Vehicle Reprogramming''.
ISO 15765-4:2001..........  ``Road Vehicles--Diagnostics on      December 2001.......  New IBR.
                             Controller Area Network (CAN)--
                             Part 4: Requirements for emission-
                             related systems''.
----------------------------------------------------------------------------------------------------------------

    Copies of these SAE materials may be obtained from Society of 
Automotive Engineers International, 400 Commonwealth Dr., Warrendale, 
PA, 15096-0001. Copies of these ISO materials may be obtained from the 
International Organization for Standardization, Case Postale 56, CH-
1211 Geneva 20, Switzerland.
2. Diagnostic Connector Requirements
    We are proposing that a standard data link connector conforming to 
either SAE J1962 or SAE J1939-13 specifications (except as noted below) 
would have to be included in each vehicle. The connector would have to 
be located in the driver's side foot-well region of the vehicle 
interior in the area bound by the driver's side of the vehicle and the 
driver's side edge of the center console (or the vehicle centerline if 
the vehicle does not have a center console) and at a location no higher 
than the bottom of the steering wheel when in the lowest adjustable 
position. The Administrator would not allow the connector to be located 
on or in the center console (i.e., neither on the horizontal faces near 
the floor-mounted gear selector, parking brake lever, or cup-holders, 
nor on the vertical faces near the car stereo, climate system, or 
navigation system controls). The location of the connector must be 
easily identifiable and accessed (e.g., to connect an off-board tool). 
For vehicles equipped with a driver's side door, the connector would 
have to be easily identified and accessed by someone standing (or 
``crouched'') on the ground outside the driver's side of the vehicle 
with the driver's side door open.
    If a manufacturer wants to cover the connector, the cover must be 
removable by hand without the use of any tools and be labeled ``OBD'' 
to aid technicians in identifying the location of the connector. Access 
to the diagnostic connector could not require opening or removing any 
storage accessory (e.g., ashtray, coinbox). The label would have to 
clearly identify that the connector is located behind the cover and is 
consistent with language and/or symbols commonly used in the automobile 
and/or heavy truck industry.
    If the ISO 15765-4 protocol (see section II.F.3) is used for the 
required OBD standardized functions, the connector would have to meet 
the ``Type A'' specifications of SAE J1962. Any pins in the connector 
that provide electrical power must be properly fused to protect the 
integrity and usefulness of the connector for diagnostic purposes and 
may not exceed 20.0 Volts DC regardless of the nominal vehicle system 
or battery voltage (e.g., 12V, 24V, 42V).
    If the SAE J1939 protocol (see section II.F.3)) is used for the 
required OBD standardized functions, the connector must meet the 
specifications of SAE J1939-13. Any pins in the connector that provide 
electrical power must be properly fused to protect the integrity and 
usefulness of the connector for diagnostic purposes.
    Manufacturers would be allowed to equip engines/vehicles with 
additional diagnostic connectors for manufacturer-specific purposes 
(i.e., purposes other than the required OBD functions). However, if the 
additional connector conforms to the ``Type A'' specifications of SAE 
J1962 or the specifications of SAE J1939-13 and is located in the 
vehicle interior near the required connector as described above, the 
connector(s) must be clearly labeled to identify which connector is 
used to access the standardized OBD information proposed below.

[[Page 3245]]

3. Communications to a Scan Tool
a. Background
    In light-duty OBD, manufacturers are allowed to use one of four 
protocols for communication between a generic scan tool and the 
vehicle's onboard computer. A generic scan tool automatically cycles 
through each of the allowable protocols until it hits upon the proper 
one with which to establish communication with the particular onboard 
computer. While this has generally worked successfully in the field, 
some communication problems have arisen.
    In an effort to address these problems, CARB has made recent 
changes to their light-duty OBD II regulation that require all light-
duty vehicle manufacturers to use only one communication protocol by 
the 2008 model year. In making these changes, CARB staff argued that 
their experience with standardization under the OBD II regulation 
showed that having a single set of standards used by all vehicles would 
be desirable. CARB staff argued that a single protocol offers a 
tremendous benefit to both scan tool designers and service technicians. 
Scan tool designers could focus on added feature content and could 
expend much less time and money validating basic functionality of their 
product on all the various permutations of protocol interpretations 
that are implemented. In turn, technicians would likely get a scan tool 
that works properly on all vehicles without the need for repeated 
software updates that incorporate ``work-arounds'' or other patches to 
fix bugs or adapt the tool to accommodate slight variances in how the 
multiple protocols interact with each other or are implemented by 
various manufacturers. Further, a single protocol should also be 
beneficial to fleet operators that use add-on equipment such as data 
loggers, and for vehicle manufacturers that integrate parts from 
various engine and component suppliers all of which must work together.
    Based on our similar experiences at the federal level with 
communication protocols giving rise to service and inspection/
maintenance program issues, we initially wanted to propose a single 
communication protocol for engines used in over 14,000 pound vehicles. 
However, the affected industry has been divided over which single 
protocol should be required and has strongly argued for more than one 
protocol to be allowed. Therefore, for vehicles with diesel engines, we 
are proposing that manufacturers be required to use either the 
standards set forth in SAE J1939, or those set forth in the 500 kbps 
baud rate version of ISO 15765. For vehicles with gasoline engines, we 
are proposing that manufacturers be required to use the 500 kbps baud 
rate version of ISO 15765. Manufacturers would be required to use only 
one standard to meet all the standardization requirements on a single 
vehicle; that is, a vehicle must use only one protocol for all OBD 
modules on the vehicle.
    Several in the heavy-duty industry have argued for options that 
would allow the use of more than these two protocols on heavy-duty 
engines. Some have even argued for combinations of these protocols--
e.g., diagnostic connector and messages of ISO 15765 on an SAE J1939 
physical layer network. However, as described above, experience from 
multiple protocols and multiple variants within the protocols has 
unnecessarily caused a significant number of problems with engine and 
vehicle related computer communications.
b. Requirements for Communications to a Scan Tool
    We are proposing that all OBD control modules--e.g., engine, 
auxiliary emission control module--on a single vehicle be required to 
use the same protocol for communication of required emissions-related 
messages from onboard to off-board network communications to a scan 
tool meeting SAE J1978 specifications or designed to communicate with a 
SAE J1939 network. Engine manufacturers would not be allowed to alter 
normal operation of the engine emissions control system due to the 
presence of off-board test equipment accessing the OBD information 
proposed below. The OBD system would be required to use one of the 
following standardized protocols:
     ISO 15765-4 and all required emission-related messages 
using this protocol would have to use a 500 kbps baud rate.
     SAE J1939 which may only be used on vehicles with diesel 
engines.
4. Required Emissions Related Functions
    Most of the proposed emissions related functions are elements that 
exist in our light-duty OBD requirements. We are proposing several 
required functions, these are:
     Readiness status
     Distance and number of warm-up cycles since DTC clear
     Permanent DTC storage
     Real time indication of monitor status
     Communicating readiness status to the vehicle operator
     Diagnostic trouble codes (DTC)
     Data stream
     Freeze frame
     Test results
     Software calibration identification
     Software calibration verification number
     Vehicle identification number (VIN)
i. Readiness Status
    The main intent of readiness status is to ensure that a vehicle is 
ready for an OBD-based inspection--by indicating that monitors have run 
and operational status of the emissions-control system has been fully 
evaluated--and to prevent fraudulent testing in inspection programs. In 
general, for OBD-based inspections, technicians ``fail'' a vehicle with 
an illuminated MIL since this would indicate the presence of an 
emissions control system malfunction. Without the readiness status 
indicators, technicians would not have a clear indication from the OBD 
system that it had sufficiently evaluated the emissions control system 
prior to the inspection. Since the potential exists for OBD checks to 
be used as part of a heavy truck inspection program, we believe that 
having readiness status indicators as part of this proposal is 
important--waiting for a subsequent OBD-I/M rulemaking to require such 
indicators would unnecessarily delay implementation of such OBD-I/M 
programs.
    Absent such OBD-I/M programs, we still believe that readiness 
indicators are an important OBD tool. Technicians would be expected to 
use the readiness status to verify OBD-related repairs. Specifically, 
technicians would clear the computer memory after repairing an OBD-
detected fault in order to erase the DTC, extinguish the MIL, and reset 
the readiness status to ``incomplete.'' Then the vehicle could be 
operated in such a manner that the monitor of the repaired component 
would run (i.e., the readiness status of the monitor would be set to 
``complete''). The absence of any DTCs or MIL illumination upon 
readiness status indicating ``complete'' would indicate a successful 
repair.
    Therefore, we are proposing that manufacturers be required to 
indicate the readiness status of the OBD monitors. This would serve to 
indicate whether or not engine operation has been sufficient to allow 
certain OBD monitors to perform their system evaluations. The OBD 
system would be required to report a readiness status of either 
``complete'' if the monitor has run a sufficient number of times to 
detect a malfunction since computer memory was last cleared, 
``incomplete'' if the monitor has not yet run a sufficient number of 
times since the memory was last cleared, or ``not applicable'' if the

[[Page 3246]]

monitor is not present or if the specific monitored component is not 
equipped on the vehicle. The readiness status of monitors that are 
required to run continuously would always indicate ``complete.'' The 
details of the proposal discussed below clarify that the readiness 
status would be set to ``incomplete'' whenever memory is cleared either 
by a battery disconnect or by a scan tool but not after a normal 
vehicle shutdown (i.e., key-off).
ii. Distance Traveled and Number of Warm-Up Cycles Since DTC Clear
    As originally envisioned in our OBD-I/M rulemaking (61 FR 40940), 
we intended to require that all readiness status indicators be set to 
``complete'' prior to accepting a vehicle for I/M inspection. However, 
it became clear that some vehicles were being rejected from inspection 
for reasons beyond the driver's control. For example, a vehicle driven 
in extreme ambient conditions would prohibit monitors from running and 
setting readiness status indicators to ``complete.'' Also, a vehicle 
repaired just prior to arriving at the inspection station may not have 
been operated sufficiently to set the readiness status of the monitor 
for the recently repaired component to ``complete.'' The driver of such 
a vehicle would, in essence, be punished unintentionally for having 
taken the time and expense to repair the vehicle just prior to the 
inspection. As a result, we issued guidance (cite) to state inspectors 
recommending that vehicles be accepted for I/M inspection provided two 
or fewer readiness status indicators are ``incomplete.'' Note that most 
light-duty gasoline vehicles--the bulk of the vehicle fleet facing OBD-
I/M checks--have only four monitors for which the readiness status 
indicator is meaningful (all of their other monitors being continuous 
monitors). However, there exists evidence that this policy is perhaps 
accepting vehicles for I/M inspection that should not be accepted due 
to unscrupulous clearing of DTCs and readiness status by people that 
understand how to do so and then operate their vehicles just enough to 
set the required minimum number of readiness indicators to 
``complete.''
    As a result, we are proposing some additional features that should 
better differentiate between vehicles that have been repaired recently 
or have ``incomplete'' readiness indicators through circumstances 
outside the driver's control, and those vehicles operated by drivers 
that are attempting to fraudulently get through an OBD-based 
inspection. We are proposing that the OBD system make available data 
that would report the distance traveled or engine run time for those 
engines that do not use vehicle speed information, and the number of 
warm-up cycles since the fault memory was last cleared.\46\ By 
combining these data with the readiness data, technicians or inspectors 
would better be able to determine if ``incomplete'' readiness status 
indicators or an extinguished MIL are due to unscrupulous memory 
clearing or circumstances beyond the driver's control. For example, a 
vehicle with several ``incomplete'' readiness indicators but with a 
high distance traveled/engine run time and a high number of warm-up 
cycles since the last clearing of fault memory would be unlikely to 
have undergone a recent fault memory clearing for the purpose of 
extinguishing the MIL prior to inspection. On the other hand, a vehicle 
with only one or two ``incomplete'' readiness indicators and a very low 
distance traveled/engine run time and a low number of warm-up cycles 
since fault memory clearing should probably be rejected or failed at an 
inspection. This would better allow an inspection program to be set up 
to reject only those vehicles with recently cleared memories while 
minimizing the chances of rejecting vehicles that driven such that 
monitors rarely run whether by unique driver behaviors or extreme 
ambient conditions.
---------------------------------------------------------------------------

    \46\ The fault memory being any DTCs, readiness status 
indicators, freeze frame information, etc.
---------------------------------------------------------------------------

iii. Permanent Diagnostic Trouble Code Storage
    Consistent with the proposal for distance traveled/engine run time 
and number of warm-up cycles, we are proposing a requirement to make it 
much more difficult for a vehicle owner or technician to clear the 
fault memory and erase all traces of a previously detected malfunction. 
Current OBD systems on under 14,000 pound vehicles allow a technician 
or vehicle owner to erase all DTCs and extinguish the MIL by issuing a 
command from a generic scan tool or, in many cases, simply by 
disconnecting the vehicle battery. This would set to ``incomplete'' the 
readiness status indicators for all monitors and would remove all 
record of the malfunction that had been detected.
    We are proposing that manufacturers be required to store in non-
volatile memory random access memory (NVRAM) a minimum of four MIL-on 
DTCs that are, at present, commanding the MIL-on. These ``permanent'' 
DTCs would have to be stored in NVRAM at the end of every key cycle. By 
requiring these permanent DTCs to be stored in NVRAM, one would not be 
able to erase them simply by disconnecting the battery. Further, 
manufacturers would not be allowed to design their OBD systems such 
that these permanent DTCs could be erased by any generic or 
manufacturer-specific scan tool command. Instead, the permanent DTCs 
could be erased only via an OBD system self-clearing--i.e., upon 
evaluating the component or system for which the permanent DTC has been 
stored and detecting on sufficient drive cycles that the malfunction is 
no longer present, the OBD system would erase the fault memory as 
discussed in section II.A.2. Once this has occurred, the permanent DTC 
stored in NVRAM would be erased also.
    The permanent DTCs should help if states choose to implement OBD-
based I/M programs for heavy trucks. A truck with readiness status 
indicators for EGR and boost control set to ``incomplete'' and with 
permanent DTCs stored for both EGR and boost control would quite 
probably be a truck that should be rejected from inspection. The OBD 
system on such a truck has almost certainly had its fault memory 
cleared--via scan tool command or battery disconnect--which would set 
the readiness indicators to ``incomplete'' and erase all MIL-on DTCs 
but would still have permanent DTCs stored (only the OBD system itself 
can erase permanent DTCs). Likewise, a truck with the same readiness 
indicators set to ``incomplete'' and no permanent DTCs for those 
monitors should almost certainly be accepted for inspection since the 
lack of readiness is almost certainly due to circumstances outside the 
driver's control.
    We believe that the permanent DTCs also provide advantages to 
technicians attempting to repair a malfunction and prepare it for 
subsequent inspection or proof of correction. The permanent DTC would 
identify the specific monitor that would need to be exercised after 
repair and prior to inspection to be sure that the malfunction has been 
repaired. By combining this information with the vehicle manufacturer's 
service information, technicians could identify the exact conditions 
necessary to exercise the particular monitor. As such, technicians 
could more effectively verify that the specific monitor (that monitor 
having illuminated the MIL for which the repair has been done) has run 
and confirmed that the malfunction no longer exists and the repair has 
been made correctly. This should also reduce vehicle owner ``come-
backs'' for incomplete or ineffective repairs.

[[Page 3247]]

iv. Real Time Indication of Monitor Status
    We are also proposing provisions to make it easier for technicians 
to prepare a vehicle for an inspection following a repair. These 
provisions would require that the OBD system provide real time data 
that indicate whether the necessary conditions are present currently to 
set all of the readiness indicators to ``complete.'' These data would 
indicate whether a particular monitor may still have an opportunity to 
run on the current drive cycle or whether a condition has been 
encountered that has disabled the monitor for the rest of the drive 
cycle regardless of the driving conditions that might be encountered. 
While these data would not provide technicians with the exact 
conditions necessary to exercise the monitors (only service information 
would provide such information), the date in combination with the 
service information should assist technicians in verifying repairs and/
or preparing a vehicle for inspection. Technicians would be able to use 
this information to identify when specific monitors have indeed 
completed or to identify situations where they have overlooked one or 
more of the enable criteria and need to check the service information 
and try again.
v. Communicating Readiness Status to the Vehicle Operator
    As mentioned above, substantial feedback has been received from 
OBD-based I/M programs throughout the U.S. Much of this feedback 
pertains to the effect on vehicle owners caused by being rejected from 
I/M inspection due to ``incomplete'' readiness status indicators. To 
address this, some light-duty vehicle manufacturers requested that they 
be allowed to communicate the vehicle's readiness status to the vehicle 
owner directly without need of a scan tool. This would provide 
assurance to the vehicle owner that their vehicle is ready for 
inspection prior to taking the vehicle to the I/M station. We are 
proposing that heavy-duty engine manufacturers be allowed to do the 
same thing (this is a proposed option, not a proposed requirement). If 
a manufacturer chooses to implement this option, though, they would be 
required to do so in a standardized manner. On engines equipped with 
this option, the owner would be able to initiate a self-check of the 
readiness status, thereby greatly reducing the possibility of being 
rejected at a roadside inspection.
vi. Diagnostic Trouble Codes (DTC)
    Malfunctions are reported by the OBD system and displayed on a scan 
tool for service technicians in the form of diagnostic trouble codes 
(DTCs). We are proposing that manufacturers be required to report all 
emissions-related DTCs using a standardized format and to make them 
accessible to all service technicians, including the independent 
service industry. The reference document standards selected by the 
manufacturer would define many generic DTCs to be used by all 
manufacturers. In the rare circumstances that a manufacturer cannot 
find within the reference documents a suitable DTC, a unique 
``manufacturer-specific'' DTC could be used. However, such 
manufacturer-specific DTCs are not as easily interpreted by the 
independent service industry. Excessive use of manufacturer-specific 
DTCs may increase the time and cost for vehicle repairs. Thus, we are 
proposing to restrict the use of manufacturer-specific DTCs. If a 
generic DTC suitable for a given malfunction cannot be found, the 
manufacturer would be expected to pursue approval and addition of 
appropriate generic DTCs into the reference documents; the intent being 
to standardize as much information as possible.
    Additionally, we are proposing that the OBD system store DTCs that 
are as specific as possible to identify the nature of the malfunction. 
The intent being to provide service technicians with as detailed 
information as possible to diagnose and repair vehicles in an efficient 
manner. In other words, manufacturers should use separate DTCs for 
every monitor where the monitor and repair procedure, or likely cause 
of the failure, is different. Generally, a manufacturer would design an 
OBD monitor that detects different root causes (e.g., sensor shorted to 
ground or battery) for a malfunctioning component or system. We would 
expect manufacturers to store a specific DTC such as ``sensor circuit 
high input'' or ``sensor circuit low input'' rather than a general code 
such as ``sensor circuit malfunction.'' Further, we expect 
manufacturers to store different DTCs that distinguish circuit 
malfunctions from rationality and functional malfunctions since the 
root cause for each is different and, thus, the repair procedures may 
be different.
    We are also proposing specific provisions for storage of pending 
and MIL-on DTCs. These proposed provisions were discussed in section 
II.A.2.
    We are also proposing requirements that would help to distinguish 
between DTCs stored for malfunctions that are currently present and for 
malfunctions that are no longer present. These requirements would apply 
only to those engines using ISO 15765-4 as the communication protocol. 
As described in section II.A.2, the OBD system would generally 
extinguish the MIL if the malfunction responsible for the MIL 
illumination has not been detected (i.e., the monitor runs and 
determines that the malfunction no longer exists) on three subsequent 
sequential drive cycles. However, a manufacturer would not be allowed 
to erase the associated MIL-on DTC until 40 engine warm-up cycles have 
occurred without again detecting the malfunction. So even though the 
malfunction is no longer present and a MIL-on is not being commanded, 
the DTC would still remain (termed a ``history'' code in the ISO 
standard). Consequently, if another unrelated malfunction occurs and 
results in a MIL-on, a new DTC would be stored along with the history 
DTC. When trying to diagnose the OBD problem, technicians accessing DTC 
information may have trouble distinguishing which DTC is responsible 
for illuminating the MIL (i.e., which malfunction is present 
currently), and thus could have trouble determining what exactly must 
be repaired. Therefore, we are proposing this requirement for ISO 
engines to help distinguish between DTCs stored for malfunctions that 
are present and those that were present. Note that, for engines using 
SAE J1939 as the communication protocol, such a distinction is already 
provided for.
    Permanent DTCs would also need to be separately identified from the 
other types of DTCs. Additionally, as described above, manufacturers 
would be required to develop additional software routines to store and 
erase permanent DTCs in NVRAM and to prevent erasure from any battery 
disconnect or scan tool command.
vii. Data Stream/Freeze Frame/Test Results
    An important aspect of OBD is the ability of technicians to access 
critical information from the onboard computer to diagnose and repair 
emissions-related malfunctions. We believe that having access through 
the diagnostic connector to real-time electronic information regarding 
certain emissions critical components and systems would provide 
valuable assistance for repairing vehicles properly. The availability 
of real-time information would also provide assistance to technicians

[[Page 3248]]

responding to drivability complaints since the vehicle could be 
operated within the necessary operating conditions and the technician 
could see how various sensors and systems were acting. Similarly, fuel 
economy complaints, loss of performance complaints, intermittent 
problems, and others issues could also be addressed.
    We are proposing a number of data parameters that the OBD system 
would be required to report to a generic scan tool. These parameters, 
which would include information such as engine speed and exhaust gas 
sensor readings, would allow technicians to understand how the vehicle 
engine control system is functioning, either as the vehicle operates in 
a service bay or during actual driving. They would also help 
technicians diagnose and repair emission-related malfunctions by 
allowing them to watch instantaneous changes in the values while 
operating the vehicle.
    Some of the data parameters we are proposing are intended to assist 
us in performing in-use testing of heavy-duty engines for compliance 
with emissions standards. One of the parameters that manufacturers 
would be required to report is the real-time status of the 
NOX and PM ``not-to-exceed'' (NTE) control areas. The NTE 
standards define a wide range of engine operating points where a 
manufacturer must design the engine to be below a maximum emission 
level. In theory, whenever the engine is operated within the speed and 
load region defined as the NTE zone, emissions will be below the 
required standards. However, within the NTE zone, manufacturers are 
allowed, if justified on a case-by-case basis, to either modify the 
time frame in which the standard must be met, and in the second case to 
be exempted from the emission standards under specific conditions 
(e.g., an NTE deficiency). Manufacturers can request two types of 
modifications: first, a five percent limited testing region within 
which no more than five percent of in-use operation is expected to 
occur and, thus, no more than five percent of NTE emissions sampling 
within that region can be compared to the NTE standard for a given 
sampling event; and second, NTE deficiencies which are precisely 
defined exemption conditions where compliance cannot be met due to 
technical reasons or for engine protection. These regions and 
conditions can be defined by directly measured signals or, in some 
cases, by complicated modeled values calculated internally in the 
engine computer. When conducting emissions testing of these engines, 
knowing if the engine is inside the NTE zone--and subject to the NTE 
standards--or is outside of the NTE zone or, perhaps, in an NTE limited 
testing region or covered by an NTE deficiency is imperative. As our 
in-use testing program requirements are written currently, we must post 
process data to determine which data points were generated within a 
compliance zone and which were generated within an exempted zone. Such 
post processing, while possible, is inefficient, time consuming, and 
resource intensive. Having the NTE zone data broadcast in real-time 
over the engine's network would allow for a much more efficient use of 
our resources.
    The specific parameters we are proposing for inclusion in the data 
stream are, for gasoline engines: calculated load value, engine coolant 
temperature, engine speed, vehicle speed, time elapsed since engine 
start, absolute load, fuel level (if used to enable or disable any 
other monitors), barometric pressure (directly measured or estimated), 
engine control module system voltage, commanded equivalence ratio, 
number of stored MIL-on DTCs, catalyst temperature (if directly 
measured or estimated for purposes of enabling the catalyst 
monitor(s)), monitor status (i.e., disabled for the rest of this drive 
cycle, complete this drive cycle, or not complete this drive cycle) 
since last engine shut-off for each monitor used for readiness status, 
distance traveled/engine run time with a commanded MIL-on, distance 
traveled/engine run time since fault memory last cleared, number of 
warm-up cycles since fault memory last cleared, OBD requirements to 
which the engine is certified (e.g., California OBD, EPA OBD, non-OBD) 
and MIL status (i.e., commanded-on or commanded-off). And, for diesel 
engines: calculated load (engine torque as a percentage of maximum 
torque available at the current engine speed),\47\ driver's demand 
engine torque (as a percentage of maximum engine torque), actual engine 
torque (as a percentage of maximum engine torque), reference engine 
maximum torque, reference maximum engine torque as a function of engine 
speed (suspect parameter numbers (SPN) 539 through 543 defined in SAE 
J1939 within parameter group number (PGN) 65251 for engine 
configuration), engine coolant temperature, engine oil temperature (if 
used for emission control or any OBD monitors), engine speed, time 
elapsed since engine start, fuel level (if used to enable or disable 
any other diagnostics), vehicle speed (if used for emission control or 
any OBD monitors), barometric pressure (directly measured or 
estimated), engine control module system voltage, number of stored MIL-
on DTCs, monitor status (i.e., disabled for the rest of this drive 
cycle, complete this drive cycle, or not complete this drive cycle) 
since last engine shut-off for each monitor used for readiness status, 
distance traveled/engine run time with a commanded MIL-on, distance 
traveled/engine run time since fault memory last cleared, number of 
warm-up cycles since DTC memory last cleared, OBD requirements to which 
the engine is certified (e.g., EPA OBD parent rating, EPA OBD child 
rating, non-OBD), and MIL status (i.e., commanded-on or commanded-off). 
Also for diesel engines, as discussed above, separate NOX 
and PM NTE control area status (i.e., inside control area, outside 
control area, inside manufacturer-specific NTE carve-out area, or 
deficiency active area). Also, for all engines so equipped (and only 
those so equipped): absolute throttle position, relative throttle 
position, fuel control system status (e.g., open loop, closed loop), 
fuel trim, fuel pressure, ignition timing advance, fuel injection 
timing, intake air/manifold temperature, engine intercooler 
(aftercooler) temperature, manifold absolute pressure, air flow rate 
from mass air flow sensor, secondary air status (upstream, downstream, 
or atmosphere), ambient air temperature, commanded purge valve duty 
cycle/position, commanded EGR valve duty cycle/position, actual EGR 
valve duty cycle/position, EGR error between actual and commanded, PTO 
status (active or not active), redundant absolute throttle position 
(for electronic throttle or other systems that utilize two or more 
sensors), absolute pedal position, redundant absolute pedal position, 
commanded throttle motor position, fuel rate, boost pressure, 
commanded/target boost pressure, turbo inlet air temperature, fuel rail 
pressure, commanded fuel rail pressure, DPF inlet pressure, DPF inlet 
temperature, DPF outlet pressure, DPF outlet temperature, DPF delta 
pressure, exhaust pressure sensor output, exhaust gas temperature 
sensor output, injection control pressure, commanded injection control 
pressure, turbocharger/turbine speed,

[[Page 3249]]

variable geometry turbo position, commanded variable geometry turbo 
position, turbocharger compressor inlet temperature, turbocharger 
compressor inlet pressure, turbocharger turbine inlet temperature, 
turbocharger turbine outlet temperature, wastegate valve position, glow 
plug lamp status, oxygen sensor output, air/fuel ratio sensor output, 
NOX sensor output, and evaporative system vapor pressure.
---------------------------------------------------------------------------

    \47\ Note that, for purposes of the calculated load and torque 
parameters for diesel engines, manufacturers would be required to 
report the most accurate values that are calculated within the 
applicable electronic control unit (e.g., the engine control 
computer). ``Most accurate values,'' in this context, would be those 
of sufficient accuracy, resolution, and filtering that they could be 
used for the purpose of in-use emissions testing with the engine 
still in a vehicle (e.g., using portable emissions measurement 
equipment).
---------------------------------------------------------------------------

    We are also proposing requirements for storage of ``freeze frame'' 
information at the time a malfunction is detected and a DTC is stored. 
The freeze frame provides the operating conditions of the vehicle at 
the time of malfunction detection and the DTC associated with the data. 
The parameters we are proposing for inclusion in the freeze frame are a 
subset of the parameters listed above for the data stream. Note that 
storage of only one freeze frame would be required. Manufacturers may 
choose to store additional frames, provided that the required frame can 
be read using a scan tool meeting SAE J1978 specifications or designed 
to communicate with an SAE J1939 network.
    We are also proposing that the OBD system store the most recent 
monitoring results for most of the major monitors. Manufacturers would 
be required to store and make available to the scan tool certain test 
information--i.e., the minimum and maximum values that should occur 
during proper operation along with the actual test value--of the most 
recent monitoring event. ``Passing'' systems would store test results 
that are within the test limits, while ``failing'' systems would store 
test results that are outside the test limits. The storage of test 
results would assist technicians in diagnosing and repairing 
malfunctions and would help distinguish between components that are 
performing well below the malfunction thresholds from those that are 
passing the malfunction thresholds marginally.
viii. Identification Numbers
    We are also proposing that manufacturers be required to report two 
identification numbers related to the software and specific calibration 
values in the onboard computer. The first item, Calibration 
Identification Number (CAL ID), would identify the software version 
installed in the onboard computer. Software is often changed following 
production of the engine. These software changes often make changes to 
the emissions control system or the OBD system. We are proposing that 
these changes include a new CAL ID and that it be communicated via the 
diagnostic connector to the scan tool. The second item, Calibration 
Verification Number (CVN), would help to ensure that the current 
software has not been corrupted, modified inappropriately, or otherwise 
tampered with. Both CAL ID and CVN help ensure the integrity of the OBD 
system. The CVN proposal would require manufacturers to develop 
sophisticated software algorithms that would essentially be a self-
check calculation of all of the emissions-related software and 
calibration values in the onboard computer and would return the result 
of the calculation to a scan tool. If the calculated result did not 
equal the expected result for that CAL ID, one would know that the 
software had been corrupted or otherwise modified. The CVN result would 
have to be made available at all times to a generic scan tool.
    We are also proposing that the Vehicle Identification Number (VIN) 
be communicated via the diagnostic connector to a generic scan tool in 
a standardized format. The VIN would be a unique number assigned by the 
vehicle manufacturer to every vehicle built. The VIN is commonly used 
for purposes of ownership and registration to uniquely identify every 
vehicle. By requiring the VIN to be stored in the onboard computer and 
available electronically to a generic scan tool, the possibility of a 
fraudulent inspection (e.g., by plugging into a different vehicle than 
an inspection citation was issued originally to generate a proof of 
correction) would be minimized. Electronic access to this number would 
also simplify the inspection process and reduce transcription errors 
from manual data entry.
    We are proposing that the VIN be electronically stored in a control 
module on the vehicle, but not that it necessarily be stored in the 
engine control module. As long as the VIN is reported correctly and 
according to the selected reference document standards, we consider it 
irrelevant as to which control module (e.g., engine controller, 
instrument cluster controller) contains the information. Further, we 
are proposing that the ultimate responsibility would lie with the 
engine manufacturer to ensure that every vehicle manufactured with one 
of its engines satisfies this requirement. However, we would expect 
that the physical task of implementing this requirement would likely be 
passed from the engine manufacturer to the vehicle manufacturer via an 
additional build specification. Thus, analogous to how the engine 
manufacturer currently provides engine purchasers with detailed 
specifications regarding engine cooling requirements, additional sensor 
inputs, physical mounting specifications, weight limitations, etc., the 
engine manufacturer would likely include an additional specification 
dictating the need for the VIN to be made available electronically. It 
would be left to each engine manufacturer to determine the most 
effective method to achieve this, as long as the VIN requirement is 
met. Some manufacturers may find it most effective to provide the 
capability in the engine control module delivered with the engine 
coupled with a mechanism for the vehicle manufacturer to program the 
module with the VIN upon installation of the engine into an actual 
vehicle. Others may find it more effective to require the vehicle 
manufacturer to have the capability built into other modules installed 
on the vehicle such as instrument cluster modules, etc. We are aware of 
several current vehicles with engines from three different engine 
manufacturers that already have the VIN available through engine-
manufacturer specific scan tools; this indicates that such arrangements 
already exist in one form or another and that they are working.
5. In-Use Performance Ratio Tracking Requirements
    To separately report an in-use performance ratio for each 
applicable monitor as discussed in sections II.B through II.D, we are 
proposing that manufacturers be required to implement software 
algorithms to report a numerator and denominator in the standardized 
format specified below and in accordance with the specifications of the 
reference documents listed in section II.F.1.
    For the numerator, denominator, general denominator, and ignition 
cycle counter:
     Each number must have a minimum value of zero and a 
maximum value of 65,535 with a resolution of one.
     Each number must be reset to zero only when a non-volatile 
random access memory (NVRAM) reset occurs (e.g., reprogramming event) 
or, if the numbers are stored in keep-alive memory (KAM), when KAM is 
lost due to an interruption in electrical power to the control module 
(e.g., battery disconnect). Numbers may not be reset to zero under any 
other circumstances including when commanded to do so via a scan tool 
command to clear DTCs or reset KAM.
     If either the numerator or denominator for a specific 
component reaches the maximum value of 65,535 2, both 
numbers should be divided by two before either is incremented again to 
avoid overflow problems.

[[Page 3250]]

     If the ignition cycle counter reaches the maximum value of 
65,535 2, the ignition cycle counter should rollover and 
increment to zero on the next ignition cycle to avoid overflow 
problems.
     If the general denominator reaches the maximum value of 
65,535 2, the general denominator should rollover and 
increment to zero on the next drive cycle that meets the general 
denominator definition to avoid overflow problems.
     If an engine is not equipped with a component (e.g., 
oxygen sensor bank 2, secondary air system), the corresponding 
numerator and denominator for that specific component should always be 
reported as zero.
    For the in-use performance ratio:
     The ratio should have a minimum value of zero and a 
maximum value of 7.99527 with a resolution of 0.000122.
     A ratio for a specific component should be considered to 
be zero whenever the corresponding numerator is equal to zero and the 
corresponding denominator is not zero.
     A ratio for a specific component should be considered to 
be the maximum value of 7.99527 if the corresponding denominator is 
zero or if the actual value of the numerator divided by the denominator 
exceeds the maximum value of 7.99527.
    For engine run time tracking on all gasoline and diesel engines, 
manufacturers would be required to implement software algorithms to 
individually track and report in a standardized format the engine run 
time while being operated in the following conditions:
     Total engine run time
     Total idle run time (with ``idle'' defined as accelerator 
pedal released by driver, vehicle speed less than or equal to one mile 
per hour, and PTO not active);
     Total run time with PTO active.
    Each of the above engine run time counters would have the following 
numerical value specifications:
     Each numerical counter must be a four-byte value with a 
minimum value of zero at a resolution of one minute per bit.
     Each numerical counter must be reset to zero only when a 
nonvolatile memory reset occurs (e.g., a reprogramming event). 
Numerical counters cannot be reset to zero under any other 
circumstances including a scan tool (generic or enhanced) command to 
clear DTCs or reset KAM.
     When any of the individual numerical counters reaches its 
maximum value, all counters must be divided by two before any are 
incremented again. This is meant to avoid overflow problems.
6. Exceptions to Standardization Requirements
    For alternative-fueled engines derived from a diesel-cycle engine, 
we are proposing that the manufacturer be allowed to meet the 
standardized requirements discussed in this section that are applicable 
to diesel engines rather than meeting the requirements applicable to 
gasoline engines.

G. Implementation Schedule, In-Use Liability, and In-Use Enforcement

1. Implementation Schedule and In-Use Liability Provisions
    Table II.G-1 summarizes the proposed implementation schedule for 
the OBD monitoring requirements--i.e., the proposed certification 
requirements and in-use liabilities. More detail regarding the 
implementation schedule and liabilities can be found in the sections 
that follow.

 Table II.G-1.--OBD Certification Requirements and In-use Liability for
Diesel Fueled and Gasoline Fueled Engines over 14,000 Pounds: Monitoring
                              Requirements
------------------------------------------------------------------------
                                        Certification
    Model year        Applicability      requirement    In-use liability
------------------------------------------------------------------------
2010-2012.........  Parent rating     Full liability    Full liability
                     within 1          to thresholds     to 2x
                     compliant         according to      thresholds. \c\
                     engine family.    certification
                     \a\               demonstration
                                       procedures. \b\
                    Child ratings     Certification     Liability to
                     within the        documentation     monitor and
                     compliant         only (i.e., no    detect as noted
                     engine family.    certification     in
                                       demonstration);   certification
                                       no liability to   documentation.
                                       thresholds.
                    All other engine  None............  None.
                     families and
                     ratings.
2013-2015.........  Parent rating     Full liability    Full liability
                     from 2010-2012    to thresholds     to 2x
                     and parent        according to      thresholds.
                     rating within 1-  certification
                     2 additional      demonstration
                     engine families.  procedures.
                    Child ratings     Full liability    Full liability
                     from 2010-2012    to thresholds     to 2x
                     and parent        but               thresholds.
                     ratings from      certification
                     any remaining     documentation
                     engine families   only.
                     or OBD
                     groups.\d\
                    Additional        Certification     Liability to
                     engine ratings.   documentation     monitor and
                                       only; no          detect as noted
                                       liability to      in
                                       thresholds.       certification
                                                         demonstration.
 2016-2018........  One rating from   Full liability    Full liability
                     1-3 engine        to thresholds     to thresholds.
                     families and/or   according to
                     OBD groups.       certification
                                       demonstration
                                       procedures.
                    Remaining         Full liability    Full liability
                     ratings.          to thresholds     to 2x
                                       but               thresholds.
                                       certification
                                       documentation
                                       only.
2019+.............  One rating from   Full liability    Full liability
                     1-3 engine        to thresholds     to thresholds.
                     families and/or   according to
                     OBD groups.       certification
                                       demonstration
                                       procedures.
                    Remaining         Full liability    Full liability
                     ratings.          to thresholds     to thresholds.
                                       but
                                       certification
                                       documentation
                                       only.
------------------------------------------------------------------------
Notes: (a) Parent and child ratings are defined in section II.G; which
  rating(s) serves as the parent rating and which engine families must
  comply is not left to the manufacturer, as discussed in section II.G.
  (b) The certification demonstration procedures and the certification
  documentation requirements are discussed in section VIII.B. (c) Where
  in-use liability to thresholds and 2x thresholds is noted,
  manufacturer liability to monitor and detect as noted in their
  certification documentation is implied. (d) OBD groups are groupings
  of engine families that use similar OBD strategies and/or similar
  emissions control systems, as described in the text.

    For the 2010 through 2012 model years, manufacturers would be 
required to implement OBD on one engine family. All other 2010 through 
2012 engine families would not be subject to any OBD requirements 
unless otherwise required to do so (e.g., to demonstrate that SCR 
equipped vehicles will not be operated without urea). For 2013,

[[Page 3251]]

manufacturers would be required to implement OBD on all engine 
families.
    We are proposing this implementation schedule for several reasons. 
First, industry has made credible arguments that their resources are 
stretched to the limit developing and testing strategies for compliance 
with the 2007/2010 heavy-duty highway emissions standards. We do not 
want to jeopardize their success toward that goal by being too 
aggressive with our OBD program. Second, OBD is a complex and difficult 
regulation with which to comply. We believe that our implementation 
schedule would give industry the opportunity to introduce OBD systems 
on a limited number of engines giving them and us very valuable 
learning experience. Should mistakes or errors in regulatory 
interpretation occur, the ramifications would be limited to only a 
subset of the new vehicle fleet rather than the entire new vehicle 
fleet. Lastly, the proposed OBD requirements outlined above, and the 
production vehicle evaluation provisions discussed in Section VIII, 
reflect 10 to 20 years of learning by EPA, CARB, and industry 
(primarily the light-duty gasoline industry) as to what works and what 
does not work. This is, perhaps, especially true for those OBD elements 
that involve the interface between the OBD system and service and I/M 
inspection personnel. Gasoline manufacturers have had the ability to 
evolve their OBD systems along with this learning process. However, 
diesel engine manufacturers have not really been involved in this 
learning process and, as a result, 100 percent implementation in 2010 
would be analogous to implementing 10 to 20 years of OBD learning in 
one implementation step. We believe that implementing in two or three 
gradual steps rather than one big step will benefit everyone involved.
    Table II.G-1 makes reference to ``parent'' and ``child'' ratings. 
In general, engine manufacturers certify an engine family that consists 
of several ratings having slightly different horsepower and/or torque 
characteristics but no differences large enough to require a different 
engine family designation. For emissions certification, the parent 
rating--i.e., the rating for which emissions data are submitted to EPA 
for the purpose of demonstrating emissions compliance--is defined as 
the ``worst case'' rating. This worst case rating is the rating 
considered as having the worst emissions performance and, therefore, 
its compliance demonstrates that all other ratings within the family 
must comply. For OBD purposes, we wanted to limit the burden on 
industry--hence the proposal for only one compliant engine family in 
2010--yet maximize the impact of the OBD system. Therefore, for model 
years 2010 through 2012, we are defining the OBD parent rating as the 
rating having the highest weighted projected sales within the engine 
family having the highest weighted projected sales, with sales being 
weighted by the useful life of the engine rating. Table II.G-2 presents 
a hypothetical example for how this would work. Using this approach, 
the OBD compliant engine family in 2010 would be the engine family 
projected to produce the most in-use emissions (based on sales weighted 
by expected miles driven). Likewise, the fully liable parent OBD rating 
would be the rating within that family projected to produce the most 
in-use emissions.

                             Table II.G-2.--Hypothetical Example of How the OBD Parent and Child Ratings Would Be Determined
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                     OBD weighting--    OBD weighting--
                                                                                       Projected       Certified    engine rating \a\  engine family \b\
                  OBD group                          Engine family         Rating        sales        useful life       (billions)         (billions)
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
I............................................  A                                 1          10,000         285,000              2.85              14.25
                                               ........................          2          40,000         285,000             11.4    .................
                                               B                                 1          10,000         435,000              4.35              21.60
                                               ........................          2          20,000         435,000              8.70   .................
                                               ........................          3          30,000         285,000              8.55   .................
II...........................................  C                                 1          20,000         110,000              2.20               7.70
                                               ........................          2          50,000         110,000              5.50   .................
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: (a) For engine family A, rating 1, 10,000 x 285,000 / 1 billion = 2.85.
(b) For engine family A, 2.85 + 11.4 = 14.25.

    In the example shown in Table II.G-2, the compliant engine family 
in 2010 would be engine family B and the parent OBD rating within that 
family would be rating 2. The other OBD compliant ratings within engine 
family B would be dubbed the ``child'' ratings. For model years 2013 
through 2015, the parent ratings would be those ratings having the 
highest weighted projected sales within each of the one to three engine 
families having the highest weighted projected sales, with sales being 
weighted by the useful life of the engine rating. In the example shown 
in Table II.G-2, the parent ratings would be rating 2 of engine family 
A, rating 2 of engine family B, and rating 2 of engine family C (Note 
that this is only for illustration purposes since our proposal would 
not require that a manufacturer with only three engine families have 
three parent ratings and instead would require only one).
    The manufacturer would not need to submit test data demonstrating 
compliance with the emissions thresholds for the child ratings. We 
would fully expect these child ratings to use OBD calibrations--i.e., 
malfunction trigger points--that are identical or nearly so to those 
used on the parent rating. However, we would allow manufacturers to 
revise the calibrations on their child ratings where necessary so as to 
avoid unnecessary or inappropriate MIL illumination. Such revisions to 
OBD calibrations have been termed ``extrapolated'' OBD calibrations 
and/or systems. The revisions to the calibrations on child ratings and 
the rationale for them would need to be very clearly described in the 
certification documentation.
    For the 2013 and later model years, we are proposing that 
manufacturers certify one to three parent ratings. The actual number of 
parent ratings would depend upon the manufacturer's fleet and would be 
based on both the emissions control system architectures present in 
their fleet and the similarities/differences of the engine families in 
their fleet. For example, a manufacturer that uses a DPF with 
NOX adsorber on each of the engines would have only one 
system architecture. Another manufacturer that uses a DPF with 
NOX adsorber on some engines and a DPF with SCR on others 
would have at least two architectures. We would expect that 
manufacturers would group similar architectures and similar engine

[[Page 3252]]

families into so called ``OBD groups.'' These OBD groups would consist 
of a combination of engines, engine families, or engine ratings that 
use the same OBD strategies and similar calibrations. The manufacturer 
would be required to submit details regarding their OBD groups as part 
of their certification documentation that shows the engine families and 
engine ratings within each OBD group for the coming model year. While a 
manufacturer may end up with more than three OBD groups, we do not 
intend to require a parent rating for more than three OBD groups. 
Therefore, in the example shown in Table II.G-2, rather than submitting 
test data for the three parent ratings as suggested above, the OBD 
grouping would result in the parent ratings being rating 2 of engine 
family B and rating 2 of engine family C. These parents would represent 
OBD groups I and II, and the manufacturer's product line. For 2013 
through 2015, we intend to allow the 2010 parent to again act as a 
parent rating and, provided no significant changes had been made to the 
engine or its emissions control system, complete carryover would be 
possible. However, for model years 2016 and beyond, we would work 
closely with CARB staff and the manufacturer to determine the parent 
ratings so that the same ratings are not acting as the parents every 
year. In other words, our definitions for the OBD parent ratings as 
discussed here apply only during the years 2010 through 2012 and again 
for the years 2013 through 2015. We request comment on this approach.
    In addition to this gradual certification implementation schedule, 
we are proposing some relaxations for in-use liability during the 2010 
through 2018 model years. The first such relaxation is higher interim 
in-use compliance standards for those OBD monitors calibrated to 
specific emissions thresholds. For the 2010 through 2015 model years, 
an OBD monitor on an in-use engine would not be considered non-
compliant (i.e., subject to enforcement action) unless emissions 
exceeded twice the OBD threshold without detection of a malfunction. 
For example, for an EGR monitor on an engine with a NOX FEL 
of 0.2 g/bhp-hr and an OBD threshold of 0.5 g/bhp-hr (i.e., the 
NOX FEL+0.3), a manufacturer would not be subject to 
enforcement action unless emissions exceeded 1.0 g/bhp-hr 
NOX without a malfunction being detected. For the model 
years 2016 through 2018, parent ratings would be liable to the 
certification emissions thresholds, but child ratings and other ratings 
would remain liable to twice the certification thresholds. Beginning in 
the 2019 model year, all families and all ratings would be liable to 
the certification thresholds.
    The second in-use relaxation is a limitation in the number of 
engines that would be liable for in-use compliance with the OBD 
emissions thresholds. For 2010 through 2012, we are proposing that 
manufacturers be fully liable in-use to twice the thresholds for only 
the OBD parent rating. The child ratings within the compliant engine 
family would have liability for monitoring in the manner described in 
the certification documentation, but would not have liability for 
detecting a malfunction at the specified emissions thresholds. For 
example, a child rating's DPF monitor designed to operate under 
conditions X, Y, and Z and calibrated to detect a backpressure within 
the range A to B would be expected to do exactly that during in-use 
operation. However, if the tailpipe emissions of the child engine were 
to exceed the applicable OBD in-use thresholds (i.e., 2x the 
certification thresholds during 2010-2015), despite having a 
backpressure within range A to B under conditions X, Y, and Z, there 
would be no in-use OBD failure nor cause for enforcement action. In 
fact, we would expect the OBD monitor to determine that the DPF was 
functioning properly since its backpressure was in the acceptable 
range. For model years 2013 through 2015, this same in-use relaxation 
would apply to those engine families that do not lie within an engine 
family for which a parent rating has been certified. For 2016 and later 
model years, all engines would have some in-use liability to 
thresholds, either the certification thresholds or twice those 
thresholds.
    These in-use relaxations are meant to provide ample time for 
manufacturers to gain experience without an excessive level of risk for 
mistakes. They would also allow manufacturers to fine-tune their 
calibration techniques over a six to ten year period.
    We are also proposing some a specific implementation schedule for 
the standardization requirements discussed in section II.F. We 
initially intended to require that any compliant OBD engine family 
would be required to implement all of the standardization requirements. 
However, we became concerned that, during model years 2010 through 
2012, we could have a situation where OBD compliant engines from 
manufacturer A might be competing against non-OBD engines from 
manufacturer B for sales in the same truck. In such a case, the truck 
builder would be placed in a difficult position of needing to design 
their truck to accommodate OBD compliant engines--along with a 
standardized MIL, a specific diagnostic connector location 
specification, etc.--and non-OBD engines. After consideration of this 
almost certain outcome, we have decided to limit the standardization 
requirements that must be met during the 2010 through 2012 model years. 
Beginning in 2013, all engines will be OBD compliant and this would 
become a moot issue. Table II.G-3 shows the proposed implementation 
schedule for standardization requirements.

  Table II.G-3.--OBD Standardization Requirements for Diesel Fueled and
               Gasoline Fueled Engines Over 14,000 Pounds
------------------------------------------------------------------------
                                          Required           Waived
    Model year        Applicability    standardization   standardization
                                          features          features
------------------------------------------------------------------------
2010-2012.........  Parent and Child  Emissions         Standardized
                     ratings within    related           connector
                     1 compliant       (II.F.4) except   (II.F.2).
                     engine family.    for the           Dedicated
                     \a\               requirement to    (i.e.,
                                       make the data     regulated OBD-
                                       available in a    only) MIL.
                                       standardized      Communication
                                       format or in      protocols
                                       accordance with   (II.F.3).
                                       SAE J1979/1939    Emissions
                                       specifications)   related
                                       . MIL             functions
                                       activation and    (II.F.4) with
                                       deactivation.\b   respect to the
                                       \ Performance     requirement to
                                       tracking--calcu   make the data
                                       lation of         available in a
                                       numerators,       standardized
                                       denominators,     format or in
                                       ratios.           accordance with
                                                         SAE J1979/1939
                                                         specifications)
                    Other engine      None............  All.
                     families.
2013+.............  All engine        All.............  None.
                     families and
                     ratings.
------------------------------------------------------------------------
Notes: (a) Parent and child ratings are defined in section II.G; which
  rating serves as the parent rating and which engine families must
  comply is not left to the manufacturer, as discussed in section II.G.
  (b) There would be no requirement for a dedicated MIL and no
  requirement to use a specific MIL symbol, only that a MIL be used and
  that it use the proposed activation/deactivation logic.


[[Page 3253]]

2. In-Use Enforcement
    When conducting our in-use enforcement investigations into OBD 
systems, we intend to use all tools we have available to analyze the 
effectiveness and compliance of the system. These tools may include on-
vehicle emission testing systems such as the portable emissions 
measurement systems (PEMS). We would also use scan tools and data 
loggers to analyze the data stream information to compare real world 
operation to the documentation provided at certification.
    Importantly, we would not intend to pursue enforcement action 
against a manufacturer for not detecting a failure mode that could not 
have been reasonably predicted or otherwise detected using monitoring 
methods known at the time of certification. For example, we are 
proposing a challenging set of requirements for monitoring of DPF 
systems. As of today, engine manufacturers are reasonably confident in 
their ability to detect certain DPF failure modes at or near the 
proposed thresholds--e.g., a leaking DPF resulting from a cracked 
substrate--but are not confident in their ability to detect some other 
DPF failure modes--e.g., a leaking DPF resulting from a partially 
melted substrate. If a partially melted substrate indeed cannot be 
detected and this is known during the certification process, we cannot 
expect such a failure to be detected on an in-use vehicle.
    We also want to make it clear who would be the responsible party 
should we pursue any in-use enforcement action with respect to OBD. We 
are very familiar with the heavy-duty industry and its tendency toward 
separate engine and component suppliers. This contrasts with the light-
duty industry which tends toward a more vertically integrated 
structure. The non-vertically integrated nature of the heavy-duty 
industry can present unique difficulties for OBD implementation and for 
OBD enforcement. With the complexity of OBD systems, especially those 
meeting the requirements being proposed today, we would expect the 
interactions between the various parties involved--engine manufacturer, 
transmission manufacturer, vehicle manufacturer, etc.--to be further 
complicated. Nonetheless, in the end the vast majority of the proposed 
OBD requirements would apply directly to the engine and its associated 
emission controls, and the engine manufacturer would have complete 
responsibility to ensure that the OBD system performs properly in-use. 
Given the central role the engine and engine control unit would play in 
the OBD system, we are proposing that the party certifying the engine 
and OBD system (typically, the engine manufacturer) be the responsible 
party for in-use compliance and enforcement actions. In this role, the 
certifying party would be our sole point of contact for potential 
noncompliances identified during in-use or enforcement testing. We 
would leave it to the engine manufacturer to determine the ultimate 
party responsible for the potential noncompliance (e.g., the engine 
manufacturer, the vehicle manufacturer, or some other supplier). In 
cases where remedial action such as an engine recall would be required, 
the certifying party would take on the responsibility of arranging to 
bring the engines or OBD systems back into compliance. Given that 
heavy-duty engines are already subject to various emission requirements 
including engine emission standards, labels, and certification, engine 
manufacturers currently impose restrictions via signed agreements with 
engine purchasers to ensure that their engines do not deviate from 
their certified configuration when installed. We would expect the OBD 
system's installation to be part of such agreements in the future.

H. Proposed Changes to the Existing 8,500 to 14,000 Pound Diesel OBD 
Requirements

    We are also proposing changes to our OBD requirements for diesel 
engines used in heavy-duty vehicles under 14,000 pounds (see 40 CFR 
86.005-17 for engine-based requirements and 40 CFR 86.1806-05 for 
vehicle or chassis-based requirements). Table II.H-1 summarizes the 
proposed changes to under 14,000 pound heavy-duty diesel emissions 
thresholds at which point a component or system has failed to the point 
of requiring an illuminated MIL and a stored DTC. Table II.H-2 
summarizes the proposed changes for diesel engines used in heavy-duty 
applications under 14,000 pounds. The proposed changes are meant to 
maintain consistency with the diesel OBD requirements we are proposing 
for over 14,000 pound applications.

 Table II.H-1.--Proposed New, or Proposed Changes to Existing, Emissions Thresholds for Diesel Fueled CI Heavy-
                                    duty Vehicles Under 14,000 Pounds (g/mi)
----------------------------------------------------------------------------------------------------------------
      Component/monitor              MY             NMHC             CO              NOX               PM
----------------------------------------------------------------------------------------------------------------
NMHC catalyst system.........  2010-2012.....  2.5x.
                               2013+.........  2x.
NOX catalyst system..........  2007-2009.....  ..............  ..............  3x............
                               2010+.........  ..............  ..............  +0.3.
DPF system...................  2010-2012.....  2.5x..........  ..............  ..............  4x.
                               2013+.........  2x............  ..............  ..............  +0.04.
Air-fuel ratio sensors         2007-2009.....  2.5x..........  2.5x..........  3x............  4x.
 upstream.
                               2010-2012.....  2.5x..........  2.5x..........  +0.3..........  +0.02.
                               2013+.........  2x............  2x............  +0.3..........  +0.02.
Air-fuel ratio sensors         2007-2009.....  2.5x..........  ..............  3x............  4x.
 downstream.
                               2010-2012.....  2.5x..........  ..............  +0.3..........  4x.
                               2013+.........  2x............  ..............  +0.3..........  +0.04.
NOX sensors..................  2007-2009.....  ..............  ..............  4x............  5x.
                               2010-2012.....  ..............  ..............  +0.3..........  4x.
                               2013+.........  ..............  ..............  +0.3..........  +0.04.
``Other monitors'' with        2007-2009.....  2.5x..........  2.5x..........  3x............  4x.
 emissions thresholds.
                               2010-2012.....  2.5x..........  2.5x..........  +0.3..........  4x.
                               2013+.........  2x............  2x............  +0.3..........  +0.02.
----------------------------------------------------------------------------------------------------------------
Notes: MY=Model Year; 2.5x means a multiple of 2.5 times the applicable emissions standard; +0.3 means the
  standard plus 0.3; not all proposed monitors have emissions thresholds but instead rely on functionality and
  rationality checks as described in section II.D.4.


[[Page 3254]]


Table II.H-2.--Proposed New, or Proposed Changes to Existing, Emissions Thresholds for Diesel Fueled CI Engines Used in Heavy-duty Vehicles Under 14,000
                                                                    Pounds (g/bhp-hr)
--------------------------------------------------------------------------------------------------------------------------------------------------------
        Component/Monitor                  MY                Std/FEL              NMHC                CO                NOX                  PM
--------------------------------------------------------------------------------------------------------------------------------------------------------
NMHC catalyst system.............  2010-2012.........  All...............  2.5x.
                                   2013+.............  All...............  2x.
NOX catalyst system..............  2007-2009.........  >0.5 NOX..........  .................  .................  1.75x.
                                   2007-2009.........  <=0.5 NOX.........  .................  .................  +0.5.
                                   2010+.............  All...............  .................  .................  +0.3.
DPF system.......................  2010-2012.........  All...............  2.5x.............  .................  .................  0.05/+0.04.
                                   2013+.............  All...............  2x...............  .................  .................  0.05/+0.04.
Air-fuel ratio sensors upstream..  2007-2009.........  >0.5 NOX..........  2.5x.............  2.5x.............  1.75x............  0.05/+0.04.
                                   2007-2009.........  <=0.5 NOX.........  2.5x.............  2.5x.............  +0.5.............  0.05/+0.04.
                                   2010-2012.........  All...............  2.5x.............  2.5x.............  +0.3.............  0.03/+0.02.
                                   2013+.............  All...............  2x...............  2x...............  +0.3.............  0.03/+0.02.
Air-fuel ratio sensors downstream  2007-2009.........  >0.5 NOX..........  2.5x.............  .................  1.75x............  0.05/+0.04.
                                   2007-2009.........  <=0.5 NOX.........  2.5x.............  .................  +0.5.............  0.05/+0.04.
                                   2010-2012.........  All...............  2.5x.............  .................  +0.3.............  0.05/+0.04.
                                   2013+.............  All...............  2x...............  .................  +0.3.............  0.05/+0.04.
NOX sensors......................  2007-2009.........  >0.5 NOX..........  .................  .................  1.75x............  0.05/+0.04.
                                   2007-2009.........  <=0.5 NOX.........  .................  .................  +0.5.............  0.05/+0.04.
                                   2010+.............  All...............  .................  .................  +0.3.............  0.05/+0.04.
``Other monitors'' with emissions  2007-2009.........  >0.5 NOX..........  2.5x.............  2.5x.............  1.75x............  0.05/+0.04.
 thresholds.
                                   2007-2009.........  <=0.5 NOX.........  2.5x.............  2.5x.............  +0.5.............  0.05/+0.04.
                                   2010-2012.........  All...............  2.5x.............  2.5x.............  +0.3.............  0.03/+0.02.
                                   2013+.............  All...............  2x...............  2x...............  +0.3.............  0.03/+0.02.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: MY=Model Year; 2.5x means a multiple of 2.5 times the applicable emissions standard or family emissions limit (FEL); +0.3 means the standard or
  FEL plus 0.3; 0.05/+0.04 means an absolute level of 0.05 or an additive level of the standard or FEL plus 0.04, whichever level is higher; not all
  proposed monitors have emissions thresholds but instead rely on functionality and rationality checks as described in section II.D.4.

1. Selective Catalytic Reduction and Lean NOX Catalyst 
Monitoring
    We are proposing that the 8,500 to 14,000 pound SCR and lean 
NOX catalyst monitoring requirements mirror those discussed 
in section II.B.6. The current regulations require detection of a 
NOX catalyst malfunction before emissions exceed 1.5x the 
emissions standards. We no longer believe that such a tight threshold 
level is appropriate for diesel SCR and lean NOX catalyst 
systems. We believe that such a tight threshold could result in too 
many false failure indications. The required monitoring conditions with 
respect to performance tracking (discussed in section II.B.6.c) would 
not apply for under 14,000 pound heavy-duty applications since we do 
not have performance tracking requirements for under 14,000 pound 
applications. We are proposing this change for the 2007 model year.
2. NOX Adsorber System Monitoring
    We are proposing that the 8,500 to 14,000 pound NOX 
adsorber monitoring requirements mirror those discussed in section 
II.B.7. The current regulations require detection of a NOX 
adsorber malfunction before emissions exceed 1.5x the emissions 
standards. We no longer believe that such a tight threshold level is 
appropriate for diesel NOX adsorber systems. We believe that 
such a tight threshold could result in too many false failure 
indications. The required monitoring conditions with respect to 
performance tracking (discussed in section II.B.7.c) would not apply 
for under 14,000 pound heavy-duty applications since we do not have 
performance tracking requirements for under 14,000 pound applications. 
We are proposing this change for the 2007 model year.
3. Diesel Particulate Filter System Monitoring
    We are proposing that the 8,500 to 14,000 pound DPF monitoring 
requirements mirror those discussed in section II.B.8. Our current 
regulations require detection of a catastrophic failure only. The 
proposed monitoring requirements discussed in section II.B.8 would be 
far more comprehensive and protective of the environment than would a 
catastrophic failure monitor. The required monitoring conditions with 
respect to performance tracking (discussed in section II.B.8.c) would 
not apply for under 14,000 pound heavy-duty applications since we do 
not have performance tracking requirements for under 14,000 pound 
applications. We are proposing no changes to the DPF monitoring 
requirements in the 2007 to 2009 model years because there is not 
sufficient lead time for manufacturers to develop a new monitor. The 
new, more stringent monitoring requirements would begin in the 2010 
model year, with a further tightening of the DPF NMHC threshold in the 
2013 model year as is also proposed for over 14,000 pound applications.
4. NMHC Converting Catalyst Monitoring
    We are proposing that the 8,500 to 14,000 pound NMHC converting 
catalyst monitoring requirements mirror those discussed in section 
II.B.5. Our current regulations do not require the monitoring of NMHC 
catalysts on diesel applications. The proposed monitoring requirements 
discussed in section II.B.5 would be far more comprehensive and 
protective of the environment than the current lack of any requirement. 
The required monitoring conditions with respect to performance tracking 
(discussed in section II.B.8.c) would not apply for under 14,000 pound 
heavy-duty applications since we do not have performance tracking 
requirements for under 14,000 pound applications. We are not proposing 
this new threshold for the 2007 to 2009 model years because there is 
not sufficient lead time for manufacturers to develop a new monitor. 
The new, more stringent monitoring requirements would begin in the 2010 
model year, with a further tightening of the NMHC threshold in the 2013 
model year as is also proposed for over 14,000 pound applications.
5. Other Monitors
    We are also proposing changes to the emissions thresholds for all 
other diesel monitors in the 8,500 to 14,000 pound range (e.g., 
NOX sensors, air fuel ratio

[[Page 3255]]

sensors, etc.). These proposed changes are meant to maintain 
consistency with the proposed changes for over 14,000 pound 
applications. We believe that these proposed thresholds are far more 
appropriate for diesel applications than the thresholds we have in our 
current OBD requirements which are, generally, 1.5 times the applicable 
standards. None of the proposed thresholds represents a new threshold 
where none currently exists. Instead, they represent different 
thresholds that would require, in most cases, malfunction detection at 
different emissions levels than would be required by our current OBD 
requirements.
6. CARB OBDII Compliance Option and Deficiencies
    We are also proposing some changes to our deficiency provisions for 
vehicles and engines meant for vehicles under 14,000 pounds. We have 
included specific mention of air-fuel ratio sensors and NOX 
sensors where we had long referred only to oxygen sensors. We have also 
updated the referenced CARB OBDII document that can be used to satisfy 
the federal OBD requirements.\48\
---------------------------------------------------------------------------

    \48\ See 13 CCR 1968.2, released August 11, 2006, Docket 
ID EPA-HQ-OAR-2005-0047-0005.
---------------------------------------------------------------------------

I. How Do the Proposed Requirements Compare to California's?

    The California Air Resources Board (CARB) has its own OBD 
regulations for engines used in vehicles over 14,000 pounds GVWR.\49\ 
(13 CCR 1971.1) In August of 2004, EPA and CARB signed a memorandum of 
agreement to work together to develop a single, nationwide OBD program 
for engines used in vehicles over 14,000 pounds.\50\ We believe that, 
for the most part, we have been successful in doing so at least for the 
early years of implementation. Nonetheless, there are differences in 
some of the details contained within each regulation. These differences 
are summarized here and we request comment on all of these differences.
---------------------------------------------------------------------------

    \49\ 13 CCR 1971.1, Docket ID EPA-HQ-OAR-2005-0047-
0006.
    \50\ ``Memorandum of Agreement: On-road Heavy-duty Diagnostic 
Regulation Development,'' signed by Chet France, U.S. EPA, and Tom 
Cackette, California ARB, August 11, 2004, Docket ID EPA-
HQ-OAR-2005-0047-0002.
---------------------------------------------------------------------------

    The first difference is that the CARB regulation contains some more 
stringent thresholds beginning in the 2013 timeframe for some engines 
and 2016 for all engines. Specifically, CARB's PM threshold for diesel 
particulate filters (DPF) and exhaust gas sensors downstream of 
aftertreatment devices, and their NOX threshold for 
NOX aftertreatment devices and exhaust gas sensors 
downstream of aftertreatment devices, become more stringent in 2013 for 
some engines and 2016 for all. We are not proposing these more 
stringent thresholds--our proposed thresholds are shown in Table II.B-
1. At this time, EPA is not in a position to propose these more 
stringent OBD thresholds for the national program. The industry 
believes that CARB's more stringent NOX and PM thresholds 
for 2013 and 2016 are not technically feasible. EPA is reviewing these 
longer term OBD thresholds, but at this time we have not made a 
decision regarding the feasibility and the appropriateness of these 
longer term thresholds. Because these thresholds do not take effect 
until model year 2013 at the earliest, we do not believe it is 
necessary to make such a determination in this rulemaking. It would be 
our intention to monitor the progress made towards complying with the 
2010 thresholds contained in today's proposal and potentially revisit 
the appropriateness of more stringent OBD thresholds for model year 
2013 and later in the future. CARB has made commitments to review their 
HD OBD program every two years and they can consider making changes to 
their long-term program during this biennial review process. EPA's 
regulatory development process does not lend itself to making updates 
every two years because the Federal rulemaking process tends to be 
lengthier than CARB's. As mentioned above, we intend to monitor the 
CARB long-term thresholds during the coming years, and if we determine 
that more stringent thresholds are appropriate, we would consider 
changing our thresholds to include the more stringent thresholds 
through a notice and comment rulemaking process.
    CARB also has some slightly different certification demonstration 
requirements in the 2011 and 2012 model years. They are requiring 
demonstration testing of the child ratings from the 2010 model year 
certified engine family for 2011 and 2012 model year certification. As 
Table II.B-1 shows, we are not requiring such demonstration testing in 
the 2011 and 2012 model years provided the child ratings meet the 
requirements of certification carry-over. Further, CARB is requiring 
that one engine rating from one to three engine families undergo full 
certification demonstration testing in the 2013 model year and every 
model year thereafter. In contrast, EPA is requiring that one to three 
engine ratings be fully demonstrated in the 2013 model year and then 
carry-over through the 2015 model year (again, provided the engine 
ratings meet the requirements of certification carry-over). In 2016 and 
subsequent model years, EPA would require that one to three engine 
ratings be fully demonstrated on an ``as needed'' basis. In the same 
vein, our evaluation protocol associated with certification 
demonstration testing, as discussed in section VIII.C, requires less 
testing than is required in CARB's regulation.
    Our OBD requirements for over 14,000 pounds do not contain any 
provisions to monitor control strategies associated with idle emission 
control strategies because EPA does not have currently any regulatory 
requirements that specifically target idle emissions control 
strategies.\51\ We are not proposing a provision to charge fees 
associated with OBD deficiencies as CARB does. We are also not 
proposing provisions for ``retroactive deficiencies'' as CARB has. Our 
deficiency provisions along with our misbuild and other in-use 
enforcement programs accomplish the same thing. Deficiencies are 
discussed in section VIII.D.\52\
---------------------------------------------------------------------------

    \51\ Note that, by idle emission control strategies we mean 
strategies that, for example, shut down the engine after 10 minutes 
of constant idle. We do not mean strategies that control emissions 
during engine idles that occur at stop lights or in congested 
traffic.
    \52\ See also proposed Sec.  86.010-18(n).
---------------------------------------------------------------------------

    For diesel engines used in heavy-duty vehicles under 14,000 pounds, 
our proposed OBD requirements are in line with those recently proposed 
by CARB.\53\ Our proposed requirements are also in line--both the 
technical aspects and the implementation timing aspects--with our 
proposed requirements for over 14,000 pound diesel applications. We are 
also proposing diesel vehicle-based OBD requirements in line with the 
proposed diesel engine-based requirements. In contrast, CARB does not 
have diesel thresholds in terms of ``grams per mile'' specified in 
their regulation for the 8,500 to 14,000 pound range.
---------------------------------------------------------------------------

    \53\ See 13 CCR 1968.2, released August 11, 2006, Docket 
ID EPA-HQ-OAR-2005-0047-0005.
---------------------------------------------------------------------------

    Specifically for gasoline engines meant for applications over 
14,000 pounds, our proposal differs from CARB's in that we are not 
requiring detection of catalysts that are less than 50 percent 
effective at converting emissions.\54\ We are not requiring this 
because we are relying on the emissions threshold of 1.75 times the 
applicable standard as a means of defining a catalyst system 
malfunction. We are also proposing some differences with respect to 
misfire monitoring. Most notably, we are not proposing a provision 
analogous

[[Page 3256]]

to CARB's provision that allows the Executive Officer to approve 
misfire monitor disablement or alternative malfunction criteria on a 
case by case basis.\55\ In general, we prefer to avoid having 
regulatory provisions that are implemented on a case by case basis. For 
similar reasons, we are also not proposing a provision analogous to 
CARB's provision that allows the Executive Officer to revise the 
orifice for evaporative leak detection if the most reliable monitoring 
strategy cannot detect the required orifice.\56\
---------------------------------------------------------------------------

    \54\ See 13 CCR 1971.1(f)(6.2.1)(B) and compare to proposed 
Sec.  86.010-18(h)(6)(ii).
    \55\ See 13 CCR 1971.1(f)(2.3.4)(D) and compare to proposed 
Sec.  86.010-18(h)(2)(iii)(D).
    \56\ See 13 CCR 1971.1(f)(7.2.3) and compare to proposed Sec.  
86.010-18(h)(7)(ii)(B) and (C).
---------------------------------------------------------------------------

III. Are the Proposed Monitoring Requirements Feasible?

    Some of the OBD monitoring strategies discussed here would be 
intrusive monitors that would result in very brief emissions increases, 
or spikes, for the sake of determining if certain emissions control 
components/systems are working properly during the remaining 99 percent 
or more of the engine's operation. While these emissions spikes are 
brief, and their levels cannot be meaningfully predicted or estimated, 
we are concerned about strategies that might give little concern to 
emissions during such spikes in favor of an easier monitor. We request 
comment on this issue--should such strategies be allowed or should such 
strategies be prohibited? If a commenter has the latter opinion, then 
suggestions should be provided for how the monitoring requirements 
should be changed to allow for a non-intrusive monitor--i.e., one that 
could run during normal operation or operation ``on the cycle''--that 
may not provide the monitoring capability nor the control expected by 
the requirements we are proposing.

A. Feasibility of the Monitoring Requirements for Diesel/Compression-
Ignition Engines

1. Fuel System Monitoring
a. Fuel Pressure Monitoring
    Manufacturers control fuel pressure by using a closed-loop feedback 
algorithm that allows them to increase or decrease fuel pressure until 
the fuel pressure sensor indicates they have achieved the desired fuel 
pressure. For the common-rail OBD systems certified in the under 14,000 
pound category, the manufacturers are monitoring the actual fuel system 
pressure sensed by a fuel rail pressure sensor, comparing it to the 
target fuel system pressure stored in a software table or calculated by 
an algorithm inside the onboard computer, and indicating a malfunction 
if the magnitude of the difference between these two exceeds an 
acceptable level. The error limits are established by engine 
dynamometer emission tests to ensure that a malfunction would be 
detected before emissions exceed the applicable thresholds.
    In cases where no fuel pressure error can generate a large enough 
emission increase to exceed the applicable thresholds, manufacturers 
are required to set the malfunction trigger at their fuel pressure 
control limits (e.g., when they reach a point where they can no longer 
increase or decrease fuel pressure to achieve the desired fuel 
pressure). This monitoring requirement has been demonstrated as 
technically feasible given that several under 14,000 pound diesels 
already meet this requirement. Further, the nature of a closed-loop 
algorithm is that such a system is inherently capable of being 
monitored because it simply requires analysis of the same closed-loop 
feedback parameter being used by the system for control purposes.
    Another promising technology is a pressure sensing glow plug. The 
glow plug is an electronic device in the cylinder of most diesel 
engines used to facilitate combustion during cold engine starting 
conditions. Glow plugs are being developed that incorporate a pressure 
sensor capable of detecting the quality of combustion within the 
cylinder.\57\ Pressure-sensing glow plugs provide feedback to the 
engine-management system that controls the timing and quantity of fuel 
injected into the cylinder. This feedback allows the engine electronics 
to adjust the injection characteristics so the engine avoids fuel-
mixture combinations that generate high levels of NOX. In 
this sense, a feedback loop is available that works like the oxygen 
sensor in a gasoline engine exhaust system. By measuring the quality of 
combustion, a determination can also be made about the quality of the 
fuel injection event--the pressure of fuel delivered, quantity of fuel 
delivered, timing of fuel delivered.
---------------------------------------------------------------------------

    \57\ ``Spotlight on Technology: Smart glowplugs may make Clean 
Diesels cost-effective Pressure-sensing units could let designers 
cut NOX aftertreatment,'' Tony Lewin, Automotive News, 
February 6, 2006.
---------------------------------------------------------------------------

b. Fuel Injection Quantity Monitoring
    Absent combustion sensors and/or pressure sensing glow plugs 
mentioned above, there is currently no feedback sensor indicating that 
the proper quantity of fuel has been injected. Therefore, injection 
quantity monitoring will be more difficult than pressure monitoring. 
Nonetheless, a manufacturer has identified a strategy currently being 
used that verifies the injection quantity under very specific engine 
operating conditions and appears to be capable of determining that the 
system is accurately delivering the desired fuel quantity. This 
strategy entails intrusive operation of the fuel injection system 
during a deceleration event where fuel injection is normally shut off 
(e.g., coasting or braking from a higher vehicle speed down to a low 
speed or a stop). During the deceleration, fuel injection to a single 
cylinder is turned back on to deliver a very small amount of fuel. 
Typically, the amount of fuel would be smaller than, or perhaps 
comparable to, the amount of fuel injected during a pilot or pre-
injection. If the fuel injection system is working correctly, that 
known injected fuel quantity will generate a known increase in 
fluctuations (accelerations) of the crankshaft that can be measured by 
the crankshaft position sensor. If too little fuel is delivered, the 
measured crankshaft acceleration will be smaller than expected. If too 
much fuel is delivered, the measured crankshaft acceleration will be 
larger than expected. This process can even be used to ``balance'' out 
each cylinder or correct for system tolerances or deterioration by 
modifying the commanded injection quantity until it produces the 
desired crankshaft acceleration and applying a correction or adaptive 
term to that cylinder's future injections. Each cylinder can, in turn, 
be cycled through this process and a separate analysis can be made for 
the performance of the fuel injection system for each cylinder. Even if 
this procedure would require only one cylinder be tested per revolution 
(to eliminate any change in engine operation or output that would be 
noticeable to the driver) and require each cylinder to be tested on 
four separate revolutions, this process would only take two seconds for 
a six cylinder engine decelerating through 1500 rpm.
    The crankshaft position sensor is commonly used to identify the 
precise position of the piston relative to the intake and exhaust 
valves to allow for very accurate fuel injection timing control and, as 
such, there exists sufficient resolution and data sampling within the 
onboard computer to enable such measurement of crankshaft 
accelerations. Further, in addition to the current use of this strategy 
in an under 14,000 pound diesel application, a nearly identical 
crankshaft fluctuation technique has been used since 1997 on under 
14,000 pound diesel engines

[[Page 3257]]

during idle conditions to determine if individual cylinders are 
misfiring.
    Another technique that may be used to achieve the same monitoring 
capability is some variation on the current cylinder balance tests used 
by many manufacturers to improve idle quality. In such strategies, 
fueling to individual cylinders is increased, decreased, or shut off to 
determine if the cylinder is contributing an equal share to the output 
of the engine. This strategy again relies on changes in crankshaft/
engine speed to measure the individual cylinder's contribution relative 
to known good values and/or the other cylinders. Such an approach seems 
viable to determine whether the fuel injection quantity is correct for 
each cylinder, but it has the disadvantage of not necessarily being 
able to verify whether the system is able to deliver small amounts of 
fuel precisely (such as those commanded during a pilot injection).
    One other approach that has been mentioned but not investigated 
thoroughly is the use of a wide-range air-fuel (A/F) sensor in the 
exhaust to confirm fuel injection quantity. The A/F sensor output could 
be compared to the measured air going into the engine and calculated 
fuel quantity injected to see if the two agree. Differences in the 
comparison may allow for the identification of incorrect fuel injection 
quantity.
c. Fuel Injection Timing Monitoring
    In the same manner as described for quantity monitoring, we believe 
that fuel injection timing could be verified. By monitoring the 
crankshaft speed fluctuation and, most notably, the time at which such 
fluctuation begins, ends, or reaches a peak, the OBD system could 
compare the time to the commanded fuel injection timing point and 
verify that the crankcase fluctuation occurred within an acceptable 
time delay relative to the commanded fuel injection. If the system was 
working improperly and actual fuel injection was delayed relative to 
when it was commanded, the corresponding crankshaft speed fluctuation 
would also be delayed and would result in a longer than acceptable time 
period between commanded fuel injection timing and crankshaft speed 
fluctuation. A more detailed discussion of this possible monitoring 
method is presented in the technical support document contained in the 
docket.\58\
---------------------------------------------------------------------------

    \58\ Draft Technical Support Document, HDOBD NPRM, EPA420-D-06-
006, Docket ID EPA-HQ-OAR-2005-0047-0008.
---------------------------------------------------------------------------

    Another possible monitoring method that has been mentioned but not 
investigated thoroughly would be to look for an electrical feedback 
signal from the injector to the computer to confirm when the injection 
occurred. Such a technique would likely use an inductive signature to 
identify exactly when an injector opened or closed and verify that it 
was at the expected timing. We expect that further investigation would 
be needed to confirm that such a monitoring technique would be 
sufficient to verify fuel injection timing.
d. Fuel System Feedback Control Monitoring
    The conditions necessary for feedback control (i.e., the feedback 
enable criteria) are defined as part of the control strategy in the 
engine computer. The feedback enable criteria are typically based on 
minimum conditions necessary for reliable and stable feedback control. 
When the manufacturer is designing and calibrating the OBD system, the 
manufacturer would determine, for the range of in-use operating 
conditions, the time needed to satisfy these feedback enable criteria 
on a properly functioning engine. In-use, the OBD system would evaluate 
the time needed for these conditions to be satisfied following an 
engine start, compare that to normal behavior for the system, and 
indicate a malfunction when the time exceeds a specified value (i.e., 
the malfunction criterion). For example, fuel pressure feedback control 
may be calibrated to begin once fuel system pressure has reached a 
minimum specified value. In a properly functioning system, pressure 
builds in the system during engine cranking and shortly after starting 
and the pressure enable criterion are reached within a few seconds. 
However, in a malfunctioning system (e.g., due to a faulty low-pressure 
fuel pump), it may take a significantly longer time to reach the 
feedback enable pressure. A malfunction would be indicated when the 
actual time to reach feedback enable pressure exceeds the malfunction 
criterion.
    Malfunctions that cause open-loop or default operation can be 
readily detected as well. As discussed above, the feedback enable 
criteria are clearly defined in the computer and are based on what is 
necessary for reliable control. After feedback control has begun, the 
OBD system can detect these criteria and indicate a malfunction when 
they are no longer being satisfied. For example, one enable criterion 
could be a pressure sensor reading within a certain range where the 
upper pressure limit would be based on the maximum pressure that could 
be generated in a properly functioning system. A malfunction would be 
indicated if the pressure sensor reading exceeded the upper limit which 
would cause the fuel system to go open loop.
    The feedback control system adjusts the base fuel strategy such 
that actual engine operating characteristics meet driver demand. But, 
the feedback control system has limits on how much adjustment can be 
made based, presumably, on the ability to maintain acceptable control. 
Like the feedback enable criteria, these control limits are defined in 
the computer. The OBD system would track the actual adjustments made by 
the control system and continuously compare them with the control 
limits. A malfunction would be indicated if the limits were reached.
    2. Engine Misfire Monitoring
    Diesel engines certified to the under 14,000 pound OBD requirements 
have been monitoring for misfire since the 1998 model year. The 
monitoring requirements we are proposing for over 14,000 pound 
applications are identical to the existing requirements for under 
14,000 pound applications for those engines that do not use combustion 
sensors.\59\ Therefore, technological feasibility has been demonstrated 
for these applications.
---------------------------------------------------------------------------

    \59\ Technically, the EPA OBD diesel misfire monitoring 
requirement for under 14,000 pound applications is to detect a lack 
of combustion whereas the California OBDII diesel misfire monitoring 
requirement is identical to what we are proposing for over 14,000 
pounds. Since all manufacturers to date are designing to the OBDII 
requirements, this statement is, for practical purposes, true.
---------------------------------------------------------------------------

    For engines that use combustion sensors, the misfire monitoring 
requirements are more stringent since the requirement calls for 
detection of malfunctions causing emissions to exceed the emissions 
thresholds. Nonetheless, detection on these engines should be straight 
forward since the combustion sensors would provide a direct measurement 
of combustion. Therefore, lack of combustion (i.e., misfire) could be 
measured directly. The combustion sensors are intended to measure 
various characteristics of a combustion event for feedback control. 
Such feedback is needed for engines that require very precise air and 
fuel metering controls such as would be required for homogeneous charge 
compression ignition (HCCI) engine. Accordingly, the resolution of 
sensors having that capability is well beyond what would be needed to 
detect a complete lack of combustion.

[[Page 3258]]

3. Exhaust Gas Recirculation (EGR) Monitoring
a. EGR Low Flow/High Flow Monitoring
    Typically, the EGR control system determines a desired EGR flow 
rate based on the engine operating conditions such as engine speed and 
engine load. The desired EGR flow rates, and the corresponding EGR 
valve positions needed to achieve the desired flow rates, are 
established when the manufacturer designs and calibrates the EGR 
system. Once established, manufacturers store the desired EGR flow 
rate/valve position in a lookup table in the onboard computer. During 
operation, the onboard computer commands the EGR valve to the position 
necessary to achieve the desired flow--i.e., the commanded EGR flow. 
The onboard computer then calculates or directly measures both the 
fresh air charge (fresh air intake) and total intake charge. The 
difference between the total intake charge and fresh air intake is the 
actual EGR flow. The closed-loop control system continuously adjusts 
the EGR valve position until the actual EGR flow equals the desired EGR 
flow.
    Such closed-loop control strategies and their associated OBD 
monitoring strategies are used on many existing gasoline and diesel 
vehicles under 14,000 pounds. The OBD system evaluates the difference 
(i.e., error) between the look-up value--i.e., the desired flow rate--
and the final commanded value needed to achieve the desired flow rate. 
Typically, as the feedback parameter or learned offset increases, there 
is an attendant increase in emissions. A correlation can be made 
between feedback adjustment and emissions. When the error exceeds a 
specific threshold, a malfunction would be indicated. This type of 
monitoring strategy could be used to detect both high and low flow 
malfunctions.
    While the closed-loop control strategy described above is effective 
in measuring and controlling EGR flow, some manufacturers are currently 
investigating the use of a second control loop based on an air-fuel 
ratio (A/F) sensor (also known as wide-range oxygen sensors or linear 
oxygen sensors) to further improve EGR control and emissions. With this 
second control loop, the desired air-fuel ratio is calculated based on 
engine operating conditions (i.e., intake airflow, commanded EGR flow 
and commanded fuel). The calculated air-fuel ratio is compared to the 
air-fuel ratio from the A/F sensor and refinements can be made to the 
EGR and airflow rates--i.e., the control can be ``trimmed''--to achieve 
the desired rates. On systems that use the second control loop, flow 
rate malfunctions could also be detected using the feedback information 
from the A/F sensor and by applying a similar monitoring strategy as 
discussed above for the primary EGR control loop.
    We are also proposing that two leaking EGR valve failure modes be 
detected. One type is the failure of the valve to seal when in the 
closed position. For example, if the valve or seating surface is 
eroded, the valve could close and seat, yet still allow some flow 
across the valve. A flow check is necessary to detect a malfunctioning 
valve that closes properly but still leaks. EGR flow--total intake 
charge minus fresh air charge--could be calculated using the monitoring 
strategy described above for high and low flow malfunctions. With the 
valve closed, a malfunction would be indicated when flow exceeds 
unacceptable levels. Or, some cooled EGR systems will incorporate an 
EGR temperature sensor that could be used to detect a leaking EGR valve 
by reacting to the presence of hot exhaust gases when none should be 
present. A leaking valve can also be caused by failure of the valve to 
close/seat. For example, carbon deposits on the valve or seat could 
prevent the valve from closing fully. The flow check described above 
could detect failure of the valve to close/seat, but this approach 
would require a repair technician to further diagnose whether the 
problem is a sealing or seating problem. Such a failure of the valve to 
close/seat could be more specifically monitored by closing the valve 
and checking the zero position of the valve with a position sensor. If 
the valve position is out of the acceptable range for a closed valve, a 
malfunction would be indicated. This type of zero position sensor check 
is commonly used to verify the closed position of valves/actuators used 
in gasoline OBD systems (e.g. gasoline EGR valves, electronic throttle) 
and should be feasible for diesel EGR valves.
b. EGR Slow Response Monitoring
    While the flow rate monitor discussed above would evaluate the 
ability of the EGR system to achieve a commanded flow rate under 
relatively steady state conditions, the EGR slow response monitor would 
evaluate the ability of the EGR system to modulate (i.e., increase and 
decrease) EGR flow as engine operating conditions and, consequently, 
commanded EGR rates change. Specifically, as engine operating 
conditions and commanded EGR flow rates change, the monitor would 
evaluate the time it takes for the EGR control system to achieve the 
commanded change in EGR flow. This monitor could evaluate EGR response 
passively during transient engine operating conditions encountered 
during in-use operation. The monitor could also evaluate EGR response 
intrusively by commanding a change in EGR flow under a steady state 
engine operating condition and measuring the time it takes to achieve 
the new EGR flow rate. Similar passive and intrusive strategies have 
been developed for variable valve control and/or timing (VVT) 
monitoring on vehicles under 14,000 pounds.
c. EGR Feedback Control Monitoring
    Monitoring of EGR feedback control could be performed using 
analogous strategies to those discussed in Section III.A.1 for 
monitoring of fuel system feedback control.
d. EGR Cooling System Monitoring
    Some diesel engine manufacturers currently use exhaust gas 
temperature sensors as an input to their EGR control systems. On such 
systems--EGR temperature--which is measured downstream of the EGR 
cooler--could be used to monitor the effectiveness of the EGR cooler. 
For a given engine operating condition (e.g., a steady speed/load that 
generates a known exhaust mass flow and exhaust temperature to the EGR 
cooler), EGR temperature will increase as the performance of the EGR 
cooling system decreases. During the OBD calibration process, 
manufacturers could develop a correlation between increased EGR 
temperatures and cooling system performance (i.e., increased 
emissions). The EGR cooling system monitor would use such a correlation 
and indicate a malfunction when the EGR temperature increases to the 
level that would cause emissions to exceed the emissions thresholds.
    While we anticipate that most, if not all, manufacturers will use 
EGR temperature sensors to meet future emissions standards, EGR cooling 
system monitoring may be feasible without such a temperature sensor. 
The monitor could be done using the intake manifold temperature (IMT) 
sensor by looking at the change in IMT (i.e., ``delta'' IMT) with EGR 
turned on and EGR turned off (IMT would be higher with EGR turned on). 
If there is significant cooling capacity with a normally functioning 
EGR cooling system, there would likely be a significant difference in 
IMT with EGR turned on versus turned off. Delta IMT could be correlated 
to decreased EGR cooling system performance and increased emissions.

[[Page 3259]]

4. Turbo Boost Control System Monitoring
a. Turbo Underboost/Overboost Monitoring
    To monitor boost control systems, manufacturers are expected to 
look at the difference between the actual pressure sensor reading (or 
calculation thereof) and the desired/target boost pressure. If the 
error between the two is too large or persists for too long, a 
malfunction would be indicated. Manufacturers would need to calibrate 
the size of error and/or error duration to ensure robust malfunction 
detection occurs before the emissions thresholds are exceeded. Given 
that the purpose of a closed-loop control system with a feedback sensor 
is to measure continuously the difference between actual and desired 
boost pressure, the control system is already monitoring that 
difference and attempting to minimize it. As such, a monitoring 
requirement to indicate a malfunction when the difference gets large 
enough such that it can no longer achieve the desired boost is 
essentially an extension of the existing control strategy.
    To monitor for malfunction or deterioration of the boost pressure 
sensors, manufacturers could validate sensor readings against other 
sensors present on the vehicle or against ambient conditions. For 
example, at initial key-on before the engine is running, the boost 
pressure sensor should read ambient pressure. If the vehicle is 
equipped with a barometric pressure sensor, the two sensors could be 
compared and a malfunction indicated when the two readings differ 
beyond the specific tolerances. A more crude rationality check of the 
boost pressure sensor could be accomplished by verifying that the 
pressure reading is within reasonable atmospheric limits for the 
conditions the vehicle will be subjected to.
b. VGT Slow Response Monitoring
    The VGT slow response monitor would evaluate the ability of the VGT 
system to modulate (i.e., increase and decrease) boost pressure as 
engine operating conditions and, consequently, commanded boost pressure 
changes. Specifically, as engine operating conditions and commanded 
boost pressures change, the monitor would evaluate the time it takes 
for the VGT control system to achieve the commanded change in boost 
pressure. This monitor could evaluate VGT response passively during 
transient engine operating conditions encountered during in-use 
operation. The monitor could also evaluate VGT response intrusively by 
commanding a change in boost pressure under a steady state engine 
operating condition and measuring the time it takes to achieve the new 
boost pressure.
    Rationality monitoring of VGT position sensors could be 
accomplished by comparing the measured sensor value to expected values 
for the given engine speed and load conditions. For example, at high 
engine speeds and loads, the position sensor should indicate that the 
VGT position is opened more than would be expected at low engine speeds 
and loads. Such rationality checks would need to be two-sided (i.e., 
position sensors should be checked for appropriate readings at both 
high and low engine speed/load operating conditions.
c. Turbo Boost Feedback Control Monitoring
    Monitoring of boost pressure feedback control could be performed 
using analogous strategies to those discussed for fuel system feedback 
control monitoring in Section III.A.1.
d. Charge Air Undercooling Monitoring
    We expect that most engines will make use of a temperature sensor 
downstream of the charge air cooler to protect against overcooling 
conditions that could cause excessive condensation, and to prevent 
undercooling that could result in loss of performance. A comparison of 
the actual charge air temperature to the expected, or design, 
temperature would indicate any errors that might be occurring. 
Manufacturers could correlate that error to an emissions impact and, 
when the error reached a level such that emissions would exceed the 
emissions thresholds, a malfunction would be indicated.
5. Non-Methane Hydrocarbon (NMHC) Converting Catalyst Monitoring
a. NMHC Converting Catalyst Conversion Efficiency Monitoring
    Monitoring of the NMHC converting catalyst, or diesel oxidation 
catalyst (DOC), could be performed similar to three-way catalyst 
monitoring on gasoline engines. Three-way catalyst monitoring uses the 
concept that catalyst's oxygen storage capacity correlates well with 
its hydrocarbon conversion efficiency. Oxygen sensors located upstream 
and downstream of the catalyst can be used to determine when its oxygen 
storage capacity--and, hence, its conversion efficiency--has 
deteriorated below a predetermined level.
    Determining the oxygen storage capacity would require lean air-fuel 
(A/F) operation followed by rich A/F operation or vice-versa during the 
catalyst monitoring event. Since a diesel engine normally operates lean 
of stoichiometry, lean A/F operation would be normal operation. 
However, rich A/F operation would have to be commanded intrusively when 
the catalyst monitor is active. The rich A/F operation could be 
achieved by injecting some fuel late enough in the four stroke process 
(i.e., late injection) that the raw fuel would not combust in-cylinder. 
Rich A/F operation could also be achieved using an in-exhaust fuel 
injector upstream of the catalyst. During normal lean operation, the 
catalyst would become saturated with stored oxygen. As a result, both 
the front and rear oxygen sensors should be reading lean. When rich A/F 
operation initiates, the front oxygen sensor would switch immediately 
to a ``rich'' indication. For a short time, the rear oxygen sensor 
should continue to read ``lean'' until such time as the stored oxygen 
in the catalyst is consumed by the rich fuel mixture in the exhaust and 
the rear oxygen sensor would read ``rich.'' As the catalyst 
deteriorates, the delay time between the front and rear oxygen sensors 
switching from their normal lean state to a rich state would become 
progressively smaller because the deteriorated catalyst would have less 
oxygen storage capacity. Thus, by comparing the time difference between 
the responses of the front and rear oxygen sensors to the lean-to-rich 
or rich-to-lean A/F changes, the performance of the catalyst could be 
estimated. Although this discussion suggests the use of conventional 
oxygen sensors, these sensors could be substituted with A/F sensors 
which would also provide for additional engine control benefits such as 
EGR trimming and fuel trimming.
    If a malfunction of the catalyst cannot cause emissions to exceed 
the emissions thresholds, then only a functional monitor would be 
required. A functional monitor could be done using temperature sensors. 
A functioning oxidation catalyst would be expected to provide some 
level of exotherm when it oxidizes HC and CO. The temperature of the 
catalyst could be measured by placing one or more temperature sensors 
at or near the catalyst. However, depending on the nominal conversion 
efficiency of the catalyst and the duty cycle of the vehicle, the 
exotherm may be difficult to discern from the inlet exhaust 
temperatures. To add robustness to the monitor, the functional monitor 
would need to be conducted during predetermined

[[Page 3260]]

operating conditions where the amount of HC and CO entering the 
catalyst could be known. This may require an intrusive monitor that 
actively forces the fueling strategy richer (e.g., through late or post 
injection) than normal for a short period of time. If the measured 
exotherm does not exceed a predetermined amount that only a properly-
working catalyst could achieve, a malfunction would be indicated. As 
noted, such an approach would require a brief period of commanded rich 
operation that would result in a very brief HC and perhaps a PM 
emissions spike.
b. Other Aftertreatment Assistance Function Monitoring
    A functional monitor should be sufficient for monitoring the 
oxidation catalyst's ability to fulfill aftertreatment assistance 
functions such as generating an exotherm for DPF regeneration or 
providing a proper feedgas for SCR or NOX adsorbers. We 
would expect that manufacturers would use the exotherm approach 
mentioned above either to measure directly for the proper exotherm or 
to correlate indirectly for the proper feedgas. For catalysts upstream 
of a DPF, we expect that this monitoring would be conducted during an 
active or forced regeneration event.\60\ For catalysts downstream of 
the DPF, we expect that manufacturers would have to add fuel 
intrusively (either in-exhaust or through in-cylinder post-injection) 
to create a sufficient exotherm to distinguish malfunctioning from 
properly operating catalysts.
---------------------------------------------------------------------------

    \60\ An active or forced regeneration would be those 
regeneration events that are initiated via a driver selectable 
switch or activator and/or those initiated by computer software.
---------------------------------------------------------------------------

6. Selective Catalytic Reduction (SCR) and NOX Conversion 
Catalyst Monitoring
a. SCR and NOX Catalyst Conversion Efficiency Monitoring
    We would expect manufacturers to use NOX sensors to 
monitor a lean NOX catalyst. NOX sensors placed 
upstream and downstream of the lean NOX catalyst could be 
used to determine directly the NOX conversion efficiency. 
Manufacturers could potentially use a single NOX sensor 
placed downstream of the catalyst to measure catalyst-out 
NOX emissions. This would have to be done within a tightly 
controlled engine operation window where engine-out NOX 
emissions (i.e., NOX emissions at the lean NOX 
catalyst inlet) performance is relatively stable and could be estimated 
reliably. Within this engine operation window, catalyst-out 
measurements could be compared to the expected engine-out 
NOX emissions and a catalyst conversion efficiency could be 
calculated. Should the calculated conversion efficiency be insufficient 
to maintain emissions below the emissions thresholds, a malfunctioning 
or deteriorated lean NOX catalyst would be indicated. If 
both an upstream and downstream NOX sensor are used for 
monitoring, the upstream sensor could be used to improve the overall 
effectiveness of the catalyst by precisely controlling the air-fuel 
ratio in the exhaust to the levels where the catalyst is most 
effective.
    For monitoring the SCR catalyst, care must be taken to account for 
the cross sensitivity of NOX sensors to ammonia 
(NH3). Current NOX sensor technology tends to 
have such a cross-sensitivity to ammonia in that as much as 65 percent 
of ammonia can be read as NOX.\61\ However, urea SCR 
feedback control studies have shown that the NH3 
interference signal is discernable from the NOX signal and 
can, in effect, allow the design of a better feedback control loop than 
a NOX sensor that doesn't have any NH3 cross-
sensitivity. In one study, a signal conditioning method was developed 
that resulted in a linear output for both NH3 and 
NOX from the NOX sensor downstream of the 
catalyst.\62\ Monitoring of the catalyst can be done by using the same 
NOX sensors that are used for SCR control. When the SCR 
catalyst is functioning properly, the upstream sensor should read 
``high'' for high NOX levels while the downstream sensor 
should read ``low'' for low NOX and low ammonia levels. With 
a deteriorated SCR catalyst, the downstream sensor should read similar 
or higher values as the upstream sensor (i.e., high NOX and 
high ammonia levels) since the NOX reduction capability of 
the catalyst has diminished. Therefore, a malfunctioning SCR catalyst 
could be detected when the downstream sensor output is near to or 
greater than the upstream sensor output. A similar monitoring approach 
could be used if a manufacturer models upstream NOX 
emissions instead of using an upstream NOX sensor. In this 
case, the comparison would be made between the modeled upstream 
NOX value and the downstream sensor value.
---------------------------------------------------------------------------

    \61\ Schaer, C.M., Onder, C.H., Geering, H.P., and Elsener, M., 
``Control of a Urea SCR Catalytic Converter System for a Mobile 
Heavy-Duty Diesel Engine,'' SAE Paper 2003-01-0776 which may be 
obtained from Society of Automotive Engineers International, 400 
Commonwealth Dr., Warrendale, PA, 15096-0001.
    \62\ Ibid.
---------------------------------------------------------------------------

    Manufacturers have expressed concern over both the sensitivity and 
the durability of NOX sensors. They are concerned that 
NOX sensors will not have the necessary sensitivity to 
detect NOX at the low levels that will exist downstream of 
the NOX catalyst. They are also concerned that 
NOX sensors will not be durable enough to last the full 
useful life of big diesel trucks. We have researched NOX 
sensors--the current state of development and future expectations--and 
summarized our findings in the technical support document in the docket 
for this rule.\63\ Some of our findings are summarized here.
---------------------------------------------------------------------------

    \63\ Draft Technical Support Document, HDOBD NPRM, EPA420-D-06-
006, Docket ID EPA-HQ-OAR-2005-0047-0008.
---------------------------------------------------------------------------

    Regarding NOX sensor sensitivity, we expect that 2010 
and later model year engines will have average tailpipe NOX 
emissions in the 0 to 50 ppm range. Current NOX sensors have 
an accuracy of 10 ppm in the 0 to 100 ppm range. This means 
that current NOX sensors should be able to detect 
NOX emissions that exceed the standard by two to three times 
the 2010 limit.\64\ This should allow for compliance with our proposed 
threshold which is effectively 2.5 times the 2010 limit. Further, we 
expect that NOX sensors in the 0 to 100 ppm range with 
5 ppm accuracy will be available by the middle of 2006. 
Regarding durability, improvements are being made and a test program is 
currently underway with the intent of aging several NOX 
sensors placed at various exhaust system locations out to 6,000 hours 
(roughly equivalent to 360,000 miles). Results after 2,000 hours of 
aging are promising and results after 4,000 hours of aging are 
currently being analyzed.\65\
---------------------------------------------------------------------------

    \64\ Ibid.
    \65\ Ibid.
---------------------------------------------------------------------------

b. SCR and NOX Catalyst Active/Intrusive Reductant Injection 
System Monitoring
    If an active catalyst system is used--i.e., one that relies on 
injection of a reductant upstream of the catalyst to assist in 
emissions conversion--manufacturers would be required to monitor the 
mechanism for adding the fuel reductant. In the active catalyst system, 
a temperature sensor is expected to be placed near or at the catalyst 
to determine when the catalyst temperature is high enough to convert 
emissions. Because NOX catalyst systems, especially lean 
NOX catalyst systems, tend to have a narrow temperature 
range where they are most effective, adding reductant when the catalyst 
temperature is not sufficiently high would waste reductant. If fuel is

[[Page 3261]]

used as the reductant, this would adversely affect fuel economy without 
a corresponding reduction in emissions levels. Therefore, a temperature 
sensor is expected to be placed in the exhaust near or at the catalyst 
to help determine when reductant injection should occur. This same 
sensor could be used to determine if an exotherm resulted following 
reductant injection. The lack of an exotherm would indicate a 
malfunction of the reductant delivery system.
    Alternatively, any NOX sensors used to monitor 
conversion efficiency could be used to determine if reductant injection 
has occurred. NOX sensors are also oxygen sensors so they 
could be used to determine the air-fuel ratio in the exhaust stream 
which would allow for verification of reductant injection into the 
exhaust. Further, with a properly functioning injector, the downstream 
NOX sensor should see a change from high NOX 
levels to low NOX levels. In contrast, a lack of reductant 
injection would result in continuously high NOX levels at 
the downstream NOX sensor. Therefore, a malfunctioning 
injector could be indicated when the downstream NOX sensor 
continues to measure high NOX after an injection event has 
been commanded.
    Reductant level monitoring could also be conducted by using the 
existing NOX sensors that are used for control purposes. 
Specifically, the downstream NOX sensor can be used to 
determine if the reductant tank no longer has sufficient reductant 
available. Similar to the fuel reductant injection functionality 
monitor described above, when the reductant tank has a sufficient 
reductant quantity and the injection system is working properly, the 
downstream NOX sensor should see a change from high 
NOX levels to low NOX levels. If the 
NOX levels remain constant both before and after reductant 
injection, then the reductant was not properly delivered and either the 
injection system is malfunctioning or there is no longer sufficient 
reductant available in the reductant tank. Alternatively, reductant 
level monitoring could be conducted by using a dedicated ``float'' type 
level sensor similar to the ones used in fuel tanks. Some manufacturers 
may prefer using a dedicated reductant level sensor in the reductant 
tank to inform the vehicle operator of current reductant levels via a 
gauge on the instrument panel. If such a sensor is used by the 
manufacturer for operator convenience, it could also be used to monitor 
the reductant level in the tank.
    Monitoring the reductant itself--whether it be the wrong reductant 
or a poor quality reductant--could also be conducted using the 
NOX sensors used for control purposes. If an improper 
reductant is injected, the NOX catalyst system would not 
function properly. Therefore, NOX emissions downstream from 
the catalyst would remain high both before and after injection. The 
downstream NOX sensor would see the high NOX 
levels after injection and a malfunction would be indicated. If the 
reductant tank level sensor indicated sufficient levels for injection 
and decreasing levels following injections (which would mean the 
injection system was working), then the probable cause of the 
malfunction would be the reductant itself. For urea SCR systems, 
another possible means of monitoring the reductant itself would be to 
use a urea quality sensor in the urea tank. First generation sensors 
show promise at verifying that urea is indeed in the tank, rather than 
water or some other fluid, and that the urea concentration is within 
the needed range (i.e., not diluted with water or some other fluid). 
The sensor could also be used in place of a urea level sensor. By 2010, 
we would expect subsequent generation sensors to provide even better 
capability.\66\
---------------------------------------------------------------------------

    \66\ Crawford, John M., Mitsui Mining & Smelting Co., Ltd., 
presentation to EPA, October 2006, Docket ID EPA-HQ-OAR-
2005-0047-0007.
---------------------------------------------------------------------------

c. SCR and NOX Catalyst Feedback Control Monitoring
    Monitoring of feedback control could be performed using analogous 
strategies to those discussed for fuel system feedback control 
monitoring in Section III.A.1.
7. NOX Adsorber Monitoring
a. NOX Adsorber Capability Monitoring
    We expect that either NOX sensors or A/F sensors along 
with a temperature sensor will be used to provide the feedback 
necessary to control the NOX adsorber system. These same 
sensors could also be used to monitor the NOX adsorber 
system's capability. The use of NOX sensors placed upstream 
and downstream of the adsorber system would allow the system's 
NOX reduction performance to be continuously monitored. For 
example, the upstream NOX sensor on a properly functioning 
adsorber system operating with lean fuel mixtures, will read high 
NOX levels while the downstream NOX sensor should 
read low NOX levels. With a deteriorated NOX 
adsorber system, the upstream NOX levels will continue to be 
high while the downstream NOX levels will also be high. 
Therefore, a malfunction of the system can be detected by comparing the 
NOX levels measured by the downstream NOX sensor 
versus the upstream sensor.
    The possibility exists that an upstream NOX sensor will 
not be used for NOX adsorber control. Manufacturers may 
choose to model engine-out NOX levels--based on engine 
operating parameters such as engine speed, fuel injection quantity and 
timing, EGR flow rate--thereby eliminating the need for the upstream 
NOX sensor. In this case, we believe that monitoring of the 
system could be conducted using A/F sensors in place of NOX 
sensors.\67\ During lean engine operation with a properly operating 
NOX adsorber system, both the upstream and downstream A/F 
sensors would indicate lean mixtures. When the exhaust gas is 
intrusively commanded rich to regenerate the NOX adsorber, 
the upstream A/F sensor would quickly indicate a rich mixture while the 
downstream sensor should continue to see a lean mixture due to the 
chemical reaction of the reducing agents with NOX and oxygen 
stored on the adsorber. Once all of the stored NOX and 
oxygen has been released, the reducing agents in the exhaust would 
cause the downstream A/F sensor to indicate a rich reading. The more 
NOX that is stored in the adsorber, the longer the delay 
between the rich indications from the upstream and downstream sensors. 
Thus, the time differential between the rich indications from the 
upstream and downstream A/F sensors is a gauge of the NOX 
storage capacity of the adsorber. This delay could be correlated to an 
emissions increase and the monitor could be calibrated to indicate a 
malfunction upon detecting an unacceptably short delay. In fact, Honda 
currently uses a similar approach to monitor the NOX 
adsorber on a 2003 model year gasoline vehicle which demonstrates the 
viability of the approach in a shorter lived application. We have 
studied A/F sensors and their durability with respect to longer lived 
diesel applications and our results are summarized in a report placed 
in the docket to this rule.\68\
---------------------------------------------------------------------------

    \67\ Ingram, G.A. and Surnilla, G., ``On-Line Estimation of 
Sulfation Levels in a Lean NOX Trap,'' SAE Paper 2002-01-
0731 may be obtained from Society of Automotive Engineers 
International, 400 Commonwealth Dr., Warrendale, PA 15096-0001.
    \68\ Draft Technical Support Document, HDOBD NPRM, EPA420-D-06-
006, Docket ID EPA-HQ-OAR-2005-0047-0008.

---------------------------------------------------------------------------

[[Page 3262]]

b. NOX Adsorber Active/Intrusive Reductant Injection System 
Monitoring
    The injection system used to achieve NOX regeneration of 
the NOX adsorber could also be monitored with A/F sensors. 
When the control system injects extra fuel to achieve a rich mixture, 
the upstream A/F sensor would respond to the change in fueling and 
could measure directly whether or not the proper amount of fuel had 
been injected. If manufacturers employ a NOX adsorber system 
design that uses only a single A/F sensor downstream of the adsorber, 
that downstream sensor could be used to monitor the performance of the 
injection system. As discussed above, the downstream sensor would 
switch from a lean reading to a rich reading when the stored 
NOX has been completely released and reduced. If the sensor 
switches too quickly after rich fueling is initiated, then either too 
much fuel has been injected or the adsorber itself has poor storage 
capability. Conversely, if the sensor takes too long to switch after 
rich fueling is initiated, it may be an indication that the adsorber 
has very good storage capability. However, excessive switch times 
(i.e., times that exceed the maximum storage capability of the 
adsorber) could be indicative of an injection system malfunction (i.e., 
insufficient fuel has been injected) or a sensor malfunction (i.e., the 
sensor has a slow response).
c. NOX Adsorber Feedback Control Monitoring
    Monitoring of feedback control could be performed using analogous 
strategies to those discussed for fuel system feedback control 
monitoring in Section III.A.1.
8. Diesel Particulate Filter (DPF) Monitoring
a. PM Filtering Performance Monitoring
    The PM filtering performance monitor is perhaps the monitor for 
which we have the most concern with respect to feasibility. Part of 
this concern stems from the difficulty in detecting the very low PM 
emissions levels required for 2007/2010 engines (i.e., 0.01 g/bhp-hr). 
While we have made changes to our test procedures that will allow for 
more accurate measurement of PM in the test cell, it is still very 
difficult to do. With today's proposal, we are expecting manufacturers 
to detect failures in the filtering performance of only a few times the 
actual standards. Success at doing so presents a very difficult 
challenge to manufacturers. Our concerns, in part, have led us to 
propose a different 2013 and later emissions threshold for this monitor 
than that proposed by ARB. This was discussed in more detail in section 
I.D.2.
    We anticipate that manufacturers can meet the proposed PM filtering 
monitor requirements without adding hardware other than that used for 
control purposes. We believe that the same pressure and temperature 
sensors that are used to control DPF regeneration will be used for OBD 
monitoring. For control purposes, manufacturers generally use a 
differential or delta pressure sensor placed across the DPF and at 
least one temperature sensor located near the DPF. The differential 
pressure sensor is expected to be used on DPF systems to prevent damage 
that could be caused by delayed or incomplete regeneration. Such 
conditions could lead to excessive temperatures and melting of the DPF 
substrate. When the differential pressure exceeds a predetermined 
level, a regeneration event would be initiated to burn the trapped PM.
    However, engine manufacturers have told us that differential 
pressure alone does not provide a robust indication of trapped PM in 
the DPF. For example, most if not all DPFs in the 2010 timeframe will 
be catalyzed DPFs that are designed to regenerate passively during most 
operation. Sometimes, conditions will not permit the passive 
regeneration and an active regeneration would have to be initiated. 
Relying solely on the differential pressure sensor to determine when an 
active regeneration event was necessary would not be sufficient. A low 
differential pressure could mean a low PM load and could also mean a 
leaking DPF substrate. A high differential pressure could mean a high 
PM load and could also mean a melted substrate. In the latter case, the 
system may continually attempt to regenerate the DPF despite a low PM 
load which would both waste fuel and increase HC emissions.
    As a result, manufacturers will probably use some sort of soot-
loading model to predict the PM load on the DPF as part of their 
regeneration strategy. Without a robust prediction, a regeneration 
event could be initiated too early (i.e., when too little PM was 
present which would be a waste of fuel and would increase HC emissions) 
or too late (i.e., when too much PM has been allowed to build and the 
regeneration event could cause a meltdown of the substrate). The model 
would estimate the PM load by tracking the difference between the 
modeled engine-out PM (i.e., the emissions that are being loaded on the 
DPF) and regenerated PM (i.e., the PM that is being burned off the DPF 
due to passive and/or active regenerations).
    Given this, we believe that a comprehensive and accurate soot-
loading model is also necessary for successful monitoring of DPF 
filtering performance. The model would predict the PM load on the DPF 
based on fuel consumption and engine operating conditions and would 
predict passively regenerated PM based on temperatures. This predicted 
PM load would be compared to the measured PM load taken from the 
differential pressure sensors. Differences would correspond to either a 
leaking substrate (i.e., predicted load greater than measured load) or 
melting of the substrate faceplate (i.e., measured load greater than 
predicted load).
    Nonetheless, much development remains to be done and success is not 
guaranteed. Manufacturers have noted that a melted substrate through 
which a large channel has opened could have differential pressure 
characteristics identical to a good substrate despite allowing most of 
the engine-out PM to flow directly through. We agree that this is a 
difficult failure mode and have proposed language that would allow 
certification of DPF monitors that are unable to detect it. Possibly, a 
temperature sensor in the DPF could detect the extreme temperatures 
capable of causing such a severe substrate melting. Upon detecting such 
a temperature, a regeneration event could be initiated to burn off any 
trapped PM. Following that event, the soot model would expect a certain 
increase in differential pressure based on modeled engine-out PM and 
passive regeneration characteristics. Presumably, the measured 
differential pressure profile would not match the predicted profile 
because most PM would be flowing straight through the melted channel. 
This same approach, or perhaps a simple temperature sensor, should 
quite easily be able to detect a missing substrate.
    Lastly, manufacturers have noted their concern that small 
differences in substrate crack size or location may generate large 
differences in tailpipe emission levels. They have also noted their 
lack of confidence that they will be able to reliably detect all leaks 
that would result in emissions exceeding the proposed thresholds. 
Accordingly, the manufacturers have suggested pursuing an alternate 
malfunction criterion independent of emission level. They have 
suggested criteria such as a percent of exhaust flow leakage or a 
specific leak or hole size that must be detected. We believe that 
pursuit of such alternate thresholds would not be appropriate at this 
time. Manufacturers have not yet completed work on initial widespread

[[Page 3263]]

implementation of DPFs for the 2007 model year. We expect that during 
the year or two following that implementation, substantial refinement 
and optimization will occur based on field experiences and that 
correlation of sensor readings to emissions levels will be possible for 
at least some DPF failure modes by the 2010 model year.
b. DPF Regeneration Monitoring
    Pressure sensing, in combination with the soot model, could also be 
used to determine if regeneration is functioning correctly. After a 
regeneration event, the differential pressure should drop significantly 
since the trapped PM has been removed. If it does not drop to within 
the soot model's predicted range after the regeneration event, either 
the regeneration did not function correctly or the filter could have 
excessive ash loading. Ash loading is a normal byproduct of engine 
operation (the ash loading is largely a function of oil consumption by 
the engine and the ash content of the engine oil). The ash builds up in 
the DPF and does not burnout as does the PM but rather must be removed 
or blown out of the DPF. Manufacturers are working with us to determine 
the necessary maintenance intervals at which this ash removal will 
occur. The soot model would have to account for ash buildup in the DPF 
with miles or hours of operation. Future engine oils will have lower 
ash content and have tighter quality control such that more accurate 
predictions of ash loading will be possible. By including ash loading 
in the soot model, we believe that its effects could be accounted for 
in the predicted differential pressure following a regeneration event.
    As stated, manufacturers are projected to make use of temperature 
sensors for regeneration control. These same sensors could also be used 
to monitor active regeneration of the filter. If excess temperatures 
are seen by the temperature sensor during active regeneration, the 
regeneration process can be stopped or slowed down to protect the 
filter. If an active regeneration event is initiated and there a 
temperature rise commensurate with the amount of trapped PM is not 
detected, the regeneration system is not working and a malfunction 
would be indicated.
c. DPF NMHC Conversion Efficiency Monitoring
    Given the stringency of the 2010 standards, we believe that 
manufactures may rely somewhat on the DPF to convert some of the HC 
emissions. The proposed requirement requires monitoring this function 
only if the system serves this function. We believe that, provided the 
filtering performance and regeneration system monitors have not 
detected any malfunctions, the NMHC conversion is probably working 
fine. Given the level of the threshold, and the expectation that the 
DPF will serve to control NMHC only marginally, we do not anticipate 
this monitor needing emissions correlation work. Instead, we expect 
that, with the DPF temperature sensor, it should be possible to infer 
adequate NMHC conversion by verifying an exotherm. Nonetheless, if a 
manufacturer relies so heavily on the DPF for NMHC conversion that its 
ability to convert could be compromised to the point of emissions 
exceeding the threshold, a more robust monitor may be required by 
correlating exotherm levels to NMHC impacts.
d. DPF Regeneration Feedback Control Monitoring
    Monitoring of DPF regeneration feedback control could be performed 
using analogous strategies to those discussed for fuel system feedback 
control monitoring in Section III.A.1.
9. Exhaust Gas Sensor Monitoring
    The under 14,000 pound OBD regulations have required oxygen sensor 
monitoring since the 1996 model year. Vehicles have been certified 
during that time meeting the requirements. The technological 
feasibility of monitoring oxygen sensors has been demonstrated. 
Additionally, A/F sensor monitoring has been required, manufacturers 
have complied, and the feasibility has been similarly demonstrated.
    NOX sensors are a recent technology and, as such, they 
are still being developed and improved. However, we would expect that 
manufacturers would design their upstream NOX sensor 
monitors to be similar the A/F sensor monitors used in under 14,000 
pound applications. Monitoring of downstream sensors may require 
modifications to existing A/F sensor strategies and/or new strategies. 
Since NOX sensors are projected to be used only for control 
and monitoring of aftertreatment systems that reduce NOX 
emissions (e.g., SCR systems), the OBD system would have to distinguish 
between deterioration of the aftertreatment system and the 
NOX sensor itself. As the aftertreatment deteriorates, 
NOX emissions downstream of the aftertreatment device will 
increase and, assuming there is no such deterioration in the 
NOX sensor, the NOX sensor will read these 
increasing NOX levels. As discussed in sections III.A.6 and 
III.A.7, the increased NOX levels can be the basis for 
monitoring the performance of the aftertreatment system. However, if 
the NOX sensor does deteriorate with the aftertreatment 
device (i.e., its response rate slows with mileage/operating hours), 
the sensor may not properly read the increasing NOX levels 
from the deteriorating aftertreatment system, and the aftertreatment 
monitor might conclude that the aftertreatment system is functioning 
properly. Similarly, the performance or level of deterioration of the 
NOX aftertreatment device could affect the results of the 
NOX sensor monitor. Therefore to achieve robust monitoring 
of aftertreatment and sensors, the OBD system has to distinguish 
between deterioration of the aftertreatment system and deterioration of 
the NOX sensor. To properly monitor the NOX 
sensor, the sensor monitor has to run under conditions where the 
aftertreatment performance can be quantified and compensated for or 
eliminated in the monitoring results.
    For example, the effects of the SCR performance could be eliminated 
by monitoring the NOX sensor under a steady-state operating 
condition during which engine-out NOX emissions were stable. 
Under a relatively steady-state condition, reductant injection could be 
``frozen'' (i.e., the reductant injection quantity could be held 
constant) which would also freeze the conversion efficiency of the SCR 
system. With SCR performance held constant, engine-out NOX 
emissions could be intrusively increased by a known amount (e.g., by 
reducing EGR flow or changing fuel injection timing and allowing the 
engine-out NOX model to determine the increase in 
emissions). The resulting increase in emissions would pass through the 
SCR catalyst unconverted, and the sensor response to the known increase 
in NOX concentrations could be measured and evaluated. This 
strategy could be used to detect both response malfunctions (i.e., the 
sensor reads the correct NOX concentration levels but the 
sensor reading does not change fast enough to keep up with changing 
exhaust NOX concentrations) and rationality malfunctions 
(i.e., the sensor reads the wrong NOX level). Rationality 
malfunctions could be detected by making sure the sensor reading 
changes by the same amount as the intrusive change in emissions. 
Lastly, the sensor response to decreasing NOX concentrations 
could also be evaluated by measuring the response when the intrusive 
strategy is turned off and engine-out NOX emissions are 
returned to normal levels. By correlating sensor response rates and the 
resulting

[[Page 3264]]

emissions impacts, the malfunction criteria could then be determined.

B. Feasibility of the Monitoring Requirements for Gasoline/Spark-
Ignition Engines

1. Fuel System Monitoring
    For gasoline vehicles since the 1996 model year and gasoline 
engines since the 2005 model year, the under 14,000 pound OBD 
requirements have required fuel system monitoring identical to that 
being proposed. Over 100 million cars and light trucks have been built 
and sold in the U.S. to these fuel system monitoring requirements 
including some heavy-duty vehicles that use the exact same gasoline 
engines that are used in some over 14,000 pound applications. This 
clearly demonstrates the technological feasibility of the proposed 
requirements.
2. Engine Misfire Monitoring
    For gasoline vehicles since the 1996 model year and gasoline 
engines since the 2005 model year, the under 14,000 pound OBD 
requirements have required misfire monitoring identical to that being 
proposed. One of the most reliable methods for detecting misfire is the 
use of a crankshaft position sensor--which measures the fluctuations in 
engine angular velocity to determine the presence of misfire--along 
with a camshaft position sensor--which can be used to identify the 
misfiring cylinder. This method has been shown to be technologically 
feasible and should work equally well on over 14,000 pound 
applications.
3. Exhaust Gas Recirculation (EGR) Monitoring
    For vehicles since the 1996 model year and engines since the 2005 
model year, the under 14,000 pound OBD requirements have required EGR 
system monitoring identical to that being proposed. The general 
approach has been to detect EGR flow rate malfunctions by looking at 
the change in fuel trim or manifold pressure under conditions when the 
EGR system is active. This demonstrates the technological feasibility 
of the proposed requirements.
4. Cold Start Emission Reduction Strategy Monitoring
    We expect this monitoring to be done mainly via computer software. 
For example, if spark retard is used during cold starts, the commanded 
amount of spark retard would have to be monitored if the amount of 
spark retard can be restricted by external factors such as idle quality 
or driveability. This can be done with software algorithms that compare 
the actual overall commanded final ignition timing with the threshold 
timing that would result in emissions that exceed the emissions 
thresholds. Cold start strategies that always command a predetermined 
amount of ignition retard independent of all other factors and do not 
allow idle quality or other factors to override the desired ignition 
retard would not require monitoring of the commanded timing. Other 
methods that could be used to ensure that the actual timing has been 
reached include verifying other factors such as corresponding increases 
in mass air flow and idle speed indicative of retarded spark 
combustion. Both mass air flow and idle speed are used currently by the 
engine control system and the OBD system and, therefore, only minor 
software modifications should be required to analyze these signals 
while the cold start strategy is invoked.
5. Secondary Air System Monitoring
    A/F sensors would most likely be required to monitor effectively 
the secondary air system when it is normally active. These sensors are 
currently installed on many new cars and their implementation is 
projected to increase in the future as more stringent emission 
standards are phased in. A/F sensors are useful in determining air-fuel 
ratio over a broader range than conventional oxygen sensors and are 
especially valuable in engines that require very precise fuel control. 
They would be useful for secondary air system monitoring because of 
their ability to determine air-fuel ratio with high accuracy. This 
would enable a correlation between secondary airflow rates and 
emissions.
6. Catalytic Converter Monitoring
    A common method used for estimating catalyst efficiency is to 
measure the catalyst's oxygen storage capacity. This monitoring method 
has been used by all light-duty gasoline vehicles since the 1996 model 
year and most gasoline engines since the 2005 model year as a result of 
our under 14,000 OBD requirements. Generally, as the catalyst's oxygen 
storage capacity decreases, the conversion efficiencies of HC and 
NOX also decrease. With this strategy, a catalyst 
malfunction would be detected when its oxygen storage capacity has 
deteriorated to a predetermined level. Manufacturers determine this by 
using the information from an upstream oxygen sensor and a downstream 
or mid-bed oxygen sensor (this second sensor is also used for trimming 
the front sensor to maintain more precise fuel control). By comparing 
the level of oxygen measured by the second sensor with that measured by 
the upstream sensor, manufacturers can determine the catalyst's oxygen 
storage capacity and estimate its conversion efficiency. With a 
properly functioning catalyst, the second oxygen sensor signal will be 
fairly steady since the fluctuating oxygen concentration (due to fuel 
system cycling around stoichiometry) at the inlet of the catalyst is 
damped by the storage and release of oxygen in the catalyst. When a 
catalyst is deteriorated it is no longer capable of storing and 
releasing oxygen. This causes the frequency and peak-to-peak voltage of 
the second oxygen sensor to simulate the signal from the upstream 
oxygen sensor at which time a malfunction would be indicated.
7. Evaporative System Monitoring
    Our OBD requirements have required monitoring for evaporative 
system leaks for many years. The EPA OBD requirement has been the 
equivalent of a 0.040 inch hole, while the ARB requirement has gone as 
low as a 0.020 inch hole. These requirements have been met on 
applications such as incomplete trucks and engine dynamometer certified 
configurations equipped with similar and, in many cases, identical 
configurations as are used in over 14,000 pound applications. 
Manufacturers have successfully met these requirements by using engine 
vacuum to create a vacuum in both the fuel tank and evaporative system 
and then monitoring the system's ability to maintain that vacuum. The 
ramp down in vacuum (or ramp up in pressure) can then be correlated to 
leak size. In general, these systems require the addition of an 
evaporative system pressure sensor and a canister vent valve capable of 
closing the vent line.
    Manufacturers of over 14,000 pound applications have expressed 
concerns with their ability to detect evaporative system leaks on these 
larger vehicles. One such concern relates to the relatively larger fuel 
tank sizes on the larger applications. These tanks can be on the order 
of 50 to 80 gallons, which makes the impact of a small hole, on a 
percentage basis, less severe and less easily detected. Another concern 
is the relatively large number of fuel tank and evaporative system 
configurations on the larger applications. Confounding both of these 
concerns is that the engine manufacturers quite often have no idea what 
tanks and configurations will ultimately be matched with their engine 
in the final vehicle product.
    While we agree that these concerns are valid, they can also be said 
of the

[[Page 3265]]

under 14,000 pound applications (except perhaps the tank size concern). 
The over 14,000 pound gasoline applications are expected to use near 
identical, if not equivalent, evaporative system components and we are 
not aware of any reason why the existing monitoring techniques would 
not continue to work on over 14,000 pound applications. Nonetheless, we 
do not want false failures in the field. By limiting the monitoring 
requirement to leaks of 0.150 inch or larger, we believe that 
manufacturers would be able to employ a single monitoring strategy to 
all possible tank sizes and configurations without much concern for 
false failures. Nonetheless, it may be necessary for manufacturers to 
impose tighter restrictions on their engine purchasers than is done 
currently with regards to tank specifications and evaporative system 
components.
8. Exhaust Gas Sensor Monitoring
    Our light-duty OBD requirements since the 1996 model year and our 
8,500 to 14,000 pound OBD requirements since the 2005 model year have 
required oxygen sensor monitoring similar to the requirements being 
proposed. Years of compliance with those requirements demonstrates the 
technological feasibility of the proposed requirements. Additionally, 
A/F sensor monitoring has been required and demonstrated on these 
vehicles for many years.

C. Feasibility of the Monitoring Requirements for Other Diesel and 
Gasoline Systems

1. Variable Valve Timing and/or Control (VVT) System Monitoring
    VVT systems are already in general use in many under 14,000 pound 
applications. Further, under the California OBD II requirements, 
vehicles equipped with VVT systems have been monitoring those systems 
for proper function since the 1996 model year. More recently, 
manufacturers have employed monitoring strategies to detect VVT system 
malfunctions that detect not only proper function but also exceedances 
of emissions thresholds. Such strategies include the use of the crank 
angle sensor and camshaft position sensor to confirm that the valve 
opening and closing occurs within an allowable tolerance of the 
commanded crank angle. By calculating the difference between the 
commanded valve opening crank angle and the achieved valve opening 
crank angle, a diagnostic algorithm can differentiate between a 
malfunctioning system with too large of an error and a properly 
functioning system with very little to no error. By calibrating the 
size of this error (or integrating it over time), manufacturers can 
design the system to indicate a malfunction prior to the required 
emissions thresholds. In the same manner, system response can be 
measured by monitoring the length of time necessary to achieve the 
commanded valve timing. To ensure adequate resolution between properly 
functioning systems and malfunctioning systems, most manufacturers 
perform this type of monitor only when a sufficiently large ``step 
change'' in commanded valve timing occurs.
2. Engine Cooling System Monitoring
    The existing OBD requirements have required identical ECT sensor 
and thermostat monitoring for several years. While the technical 
feasibility of the proposed requirements has been demonstrated on 
lighter applications which tend to be produced through a vertically 
integrated manufacturing process, the manufacturers of big diesel 
engines have expressed concerns that monitoring of the cooling system 
on over 14,000 pound applications would create unique and possibly 
insurmountable challenges. Generally, the cooling system is divided 
into two cooling circuits connected by the thermostat. The two circuits 
are the engine circuit and the radiator circuit. Since the big diesel 
engine industry tends to be horizontally integrated, the manufacturers 
contend that they do not know what types of devices will be added to 
the cooling system when the vehicle is manufactured or the vehicle is 
put into service. They are concerned that the unknown devices can add/
remove unknown quantities of heat to/from the system which would 
prevent them from predicting reliably the proper system behavior (e.g., 
warm up). Without the ability to predict system behavior reliably, they 
fear that they cannot know when the system is malfunctioning (e.g., not 
warming up as expected).
    The industry's concerns regarding unknown devices added on the 
radiator circuit of the system seem unwarranted. A properly functioning 
thermostat does not allow flow through the radiator during warm-up. 
Devices added to the radiator circuit could only affect coolant 
temperature when there is significant coolant flow through the radiator 
(i.e., after the engine is warmed-up and the thermostat is open, 
allowing coolant to flow through the radiator).
    We agree that unknown devices added on the engine circuit (e.g., 
passenger compartment heaters) can affect the warm-up rate of the 
system. Manufacturers of under 14,000 pound applications have 
demonstrated robust thermostat monitoring with high capacity passenger 
heaters in the cooling system. To do so, they have to know the maximum 
rate of heat loss due to the heater. Manufacturers of over 14,000 pound 
applications have control over this by providing limits on such devices 
in the build specifications that they provide to the vehicle 
manufacturers. In some cases, an engine manufacturer might need 
multiple build specifications with corresponding thermostat monitoring 
calibrations to accommodate the ranges of heater capacities that are 
needed when a given engine is used in a range of vehicle applications 
(e.g., a local delivery truck having a passenger compartment for two 
people and a small capacity heater versus a bus having a passenger 
compartment for 20 people and a large capacity heater). The vehicle 
manufacturer would then select the appropriate calibration for the 
engine when installing it in the vehicle. Nonetheless, engine 
manufacturers have requested limited enable conditions for the 
thermostat monitor (e.g., to disable the thermostat monitor below 50 
degrees F). This would help to minimize their resource needs to 
calibrate the thermostat monitor. While this may be directionally 
favorable to manufacturers, it would result in disabled thermostat 
monitoring during cold ambient conditions which occur in much of the 
country and, in some areas, during a large portion of the year. In such 
regions, a vehicle could experience a thermostat malfunction with no 
indication to the vehicle operator. Since many other OBD monitors will 
operate only after reaching a certain engine coolant temperature, a 
malfunctioning thermostat without any indication could effectively 
result in disablement of the OBD system.
3. Crankcase Ventilation System Monitoring
    Crankcase ventilation system monitoring requirements have been met 
for years by manufacturers of under 14,000 pound gasoline applications. 
Therefore, the technological feasibility has been demonstrated for 
gasoline applications.
    Effectively, diesel engine manufacturers would be required to meet 
design requirements for the entire system in lieu of actually 
monitoring any of the hoses for disconnection. Specifically, the 
proposed requirement would allow for an exemption for any portion of 
the system that is resistant to deterioration or accidental 
disconnection and not subject to disconnection during any of the

[[Page 3266]]

manufacturer's repair procedures for non-crankcase ventilation system 
repair work. These safeguards would be expected to eliminate the 
chances of disconnected or improperly connected hoses while still 
allowing manufacturers to meet the requirements without adding any 
additional hardware meant solely for the purpose of meeting the 
monitoring requirements.
4. Comprehensive Component Monitoring
    Both ARB and EPA OBD requirements have for year contained 
requirements to monitor computer input and output components. While 
these monitors are sometimes tricky and are not easy as many 
incorrectly assume, the many years of successful implementation and 
compliance with the existing requirements demonstrates their 
feasibility. The proposed requirements are equivalent to the under 
14,000 pound requirements.

IV. What Are the Service Information Availability Requirements?

A. What Is the Important Background Information for the Proposed 
Service Information Provisions?

    Section 202(m)(5) of the CAA directs EPA to promulgate regulations 
requiring OEMs to provide to:

any person engaged in the repairing or servicing of motor vehicles 
or motor vehicle engines, and the Administrator for use by any such 
persons, * * * any and all information needed to make use of the 
[vehicle's] emission control diagnostic system * * * and such other 
information including instructions for making emission-related 
diagnoses and repairs.

    Such requirements are subject to the requirements of section 208(c) 
regarding protection of trade secrets; however, no such information may 
be withheld under section 208(c) if that information is provided 
(directly or indirectly) by the manufacturer to its franchised dealers 
or other persons engaged in the repair, diagnosing or servicing of 
motor vehicles.
    On June 27, 2003 EPA published a final rulemaking (68 FR 38428) 
which set forth the Agency's service information regulations for light- 
and heavy-duty vehicles and engines below 14,000 pounds GVWR. These 
regulations, in part, required each-covered Original Equipment 
Manufacturer (OEM) to do the following: (1) OEMs must make full text 
emissions-related service information available via the World Wide Web. 
(2) OEMs must provide equipment and tool companies with information 
that allows them to develop pass-through reprogramming tools. (3) OEMs 
must make available enhanced diagnostic information to equipment and 
tool manufacturers and to make available OEM-specific diagnostic tools 
for sale. These requirements were finalized to ensure that aftermarket 
service and repair facilities have access to the same emission-related 
service information, in the same or similar manner, as that provided by 
OEMs to their franchised dealerships.
    As EPA moves forward proposing OBD requirements for the heavy-duty 
over 14,000 pounds sector, EPA is similarly moving forward with 
proposals to require the availability of service information to heavy-
duty aftermarket service providers as required by section 202(m) of the 
Clean Air Act.
    All of the following proposed provisions regarding the availability 
of service information for the heavy-duty industry are based on our 
extensive experience and regulatory history with the light-duty service 
industry. However, as discussed below, EPA understands that there may 
be significant differences between the light-duty service industry and 
the heavy-duty service industry. EPA welcomes comment on all of the 
proposed provisions and their need and/or applicability to the heavy-
duty service industry.
B. How Do the Below 14,000 Pound and Above 14,000 Pounds Aftermarket 
Service Industry Compare?
    As we consider proposing the availability of service information 
for the heavy-duty sector above 14,000 pounds, EPA recognizes that 
differences do exist between the industries that service vehicles above 
and below 14,000 pounds. On the below 14,000 pound side, estimates 
indicate that independent technicians perform up to 80% of all vehicle 
service and repairs once a vehicle exceeds the manufacturer warranty 
period.\69\ On the above 14,000 pound side, the 1997 U.S. Census Bureau 
Vehicle Inventory and Use Survey, estimated that 25 percent of the 
general maintenance and over 30 percent of the major overhaul on heavy-
duty vehicles was performed by the independent sector. According to the 
Census Bureau, these values represent a 16.7 percent increase in 
general maintenance and a 6.2 percent increase in major overhaul from 
1992. Trucks and Parts Service Magazine provides the following 
information on the breakdown of the independent repair industry for 
vehicles above 14,000 pounds (not including any fuel injection shops):
---------------------------------------------------------------------------

    \69\ Motor and Equipment Manufacturers Association, Automotive 
Industry Status Report, 1999.

U.S. independent machine shops for above 14,000 pounds--5,820
U.S. independent engine service shops for above 14,000 pounds--12,170
U.S. independent transmission repair shops for above 14,000 pounds--
11,420
Technicians, independent repair shops for above 14,000 pounds--133,700
Technicians, truck parts distributors for vehicles above 14,000 
pounds--41,600

    Thus, the increase in business and the large number of independent 
aftermarket shops make it necessary that repair information is readily 
available for the aftermarket trucking industry.
    On the light-duty side, vehicle manufacturers are entirely 
integrated in that they are responsible for the design and production 
of the entire vehicle from the chassis to the body. In comparison, the 
heavy-duty industry is mostly non-integrated. In other words, different 
manufacturers separately produce the engine, the chassis, and the 
transmission of a vehicle. This non-integration speaks to the fact that 
a completed vehicle is typically produced in response to the customized 
needs of owners/operators. In addition, the lack of integration 
indicates that a given engine will ultimately be part of many different 
engine, transmission, and chassis configurations. In addition, heavy-
duty manufacturers have stated that diagnostic tool designs differ 
significantly from tools produced for light-duty vehicles as a result 
of this non-integration.
    EPA requests comment and also additional data on the current state 
of the heavy-duty aftermarket industry.

C. What Provisions Are Being Proposed for Service Information 
Availability?

1. What Information Is Proposed To Be Made Available by OEMs?
    Today's action proposes a provision that requires OEMs to make 
available to any person engaged in the repairing or servicing of heavy-
duty motor vehicles or motor vehicle engines above 14,000 pounds all 
information necessary to make use of the OBD systems and any 
information for making emission-related repairs, including any 
emissions-related information that is provided by the OEM to franchised 
dealers beginning with MY2010. We are proposing that this information 
includes, but is not limited to, the following:
    (1) Manuals, technical service bulletins (TSBs), diagrams, and 
charts (the provisions for training materials,

[[Page 3267]]

including videos and other media are discussed in Sections II.C.3 and 
II.C.4 below.
    (2) A general description of the operation of each monitor, 
including a description of the parameter that is being monitored.
    (3) A listing of all typical OBD diagnostic trouble codes 
associated with each monitor.
    (4) A description of the typical enabling conditions for each 
monitor to execute during vehicle operation, including, but not limited 
to, minimum and maximum intake air and engine coolant temperature, 
vehicle speed range, and time after engine startup. A listing and 
description of all existing monitor-specific drive cycle information 
for those vehicles that perform misfire, fuel system, and comprehensive 
component monitoring.
    (5) A listing of each monitor sequence, execution frequency and 
typical duration.
    (6) A listing of typical malfunction thresholds for each monitor.
    (7) For OBD parameters that deviate from the typical parameters, 
the OBD description shall indicate the deviation for the vehicles it 
applies to and provide a separate listing of the typical values for 
those vehicles.
    (8) Identification and scaling information necessary to interpret 
and understand data available to a generic scan tool through Diagnostic 
Message 8 pursuant to SAE Recommended Practice J1939-73, which is 
incorporated by reference in section X.
    (9) For vehicles below 14,000 pounds, EPA requires that any 
information related to the service, repair, installation or replacement 
of parts or systems developed by third party (Tier 1) suppliers for 
OEMs, to the extent they are made available to franchise dealerships. 
EPA believes that Tier 1 suppliers are an important element of the 
market related to vehicles below 14,000 pounds and EPA is requesting 
comment on the role that Tier 1 suppliers play in the heavy-duty market 
above 14,000 pounds and the need to extend this provision to the heavy-
duty industry above 14,000 pounds.
    (10) Any information on other systems that can directly effect the 
emission system within a multiplexed system (including how information 
is sent between emission-related system modules and other modules on a 
multiplexed bus),
    (11) Any information regarding any system, component, or part of a 
vehicle monitored by the OBD system that could in a failure mode cause 
the OBD system to illuminate the malfunction indicator light (MIL).
    (12) Any other information relevant to the diagnosis and completion 
of an emissions-related repair. This information includes, but is not 
limited to, information needed to start the vehicle when the vehicle is 
equipped with an anti-theft or similar system that disables the engine 
described below in paragraph (13). This information also includes any 
OEM-specific emissions-related diagnostic trouble codes (DTCs) and any 
related service bulletins, trouble shooting guides, and/or repair 
procedures associated with these OEM-specific DTCs.
    (13) For vehicles below 14,000 pounds, EPA requires that OEMs make 
available computer or anti-theft system initialization information 
necessary for the proper installation of on-board computers on motor 
vehicles that employ integral vehicle security systems or the repair or 
replacement of any other emission-related part. We did not finalize a 
provision that would require OEMs to make this information available on 
the OEM's Web site unless they chose to do so. However, we did finalize 
a provision requiring that the OEM's Web site contain information on 
alternate means for obtaining the information and/or ability to perform 
reintialization. EPA is proposing to expand this provision to OEMs for 
vehicles above 14,000 pounds and requests comment on the prevalence of 
this type of repair, the means and methods for performing this type of 
repair and the need to extend this provision to the heavy-duty 
industry.
    In addition, EPA's current service information rules require that, 
beginning with the 2008 model year, all OEM systems will be designed in 
such a way that no special tools or processes will be necessary to 
perform re-initialization. In other words, EPA expects that the re-
initialization of vehicles can be completed with generic aftermarket 
tools, a pass-through device, or an inexpensive OEM-specific cable. EPA 
finalized this provision for vehicles below 14,000 pounds to prevent 
the need for aftermarket service providers to invest in expensive OEM-
specific or specialty tools to complete an emissions-related repair 
that does not occur very frequently, but does in fact occur. In the 
June 2003 final rule, EPA gave OEMs a significant amount of lead time 
to either separate the need for reinitialization from an emissions 
related repair or otherwise redesign the reinitialization process in 
such a way that it does not require the use of special tools. EPA 
requests comment on the need for such a provision for the above 14,000 
pound market. To the extent that such a provision may be needed for the 
heavy-duty arena, EPA also requests comment and what lead-time might be 
needed to meet EPA's goal of not relying on special tools or processes 
to perform reinitialization.
    Information for making emission-related repairs does not include 
information used to design and manufacture parts, but may include OEM 
changes to internal calibrations, and other indirect information, as 
discussed below.
2. What Are the Proposed Requirements for Web-Based Delivery of the 
Required Information?
a. OEM Web Sites
    Today's action proposes a provision that would require OEMs to make 
available in full-text all of the information outlined above, on 
individual OEM Web sites. Today's action further proposes that each OEM 
launch their individual Web sites with the required information within 
6 months of publication of the final rule for all 2010 and later model 
year vehicles. The only proposed exceptions to the full-text 
requirements are training information, anti-theft information, and 
indirect information.
b. Timeliness and Maintenance of Information on OEM Web Sites
    Today's action proposes a provision that would require OEMs to make 
available the required information on their Web site within six months 
of model introduction. After this six month period, we propose that the 
required information for each model must be available and updated on 
the OEM Web site at the same time it is available by any means to their 
dealers.
    For vehicles under 14,000 pounds, EPA finalized a provision that 
OEMs maintain the required information in full text on their Web sites 
for at least 15 years after model introduction. After this fifteen-year 
period, OEMs can archive the required service information, but it must 
be made available upon request, in a format of the OEM's choice (e.g. 
CD-ROM). Given the significantly longer lifetime of heavy-duty vehicles 
and engines above 14,000 pounds, EPA requests comment on the need to 
require that the required information be required to remain on the Web 
sites for a longer period of time.
c. Accessibility, Reporting and Performance Requirements for OEM Web 
Sites
    Performance reports that adequately demonstrate that their 
individual Web sites meets the requirements outlined in Section C(1) 
above will be submitted to the Administrator annually or upon

[[Page 3268]]

request by the Administrator. These reports shall also indicate the 
performance and effectiveness of the Web sites by using commonly used 
Internet statistics (e.g. successful requests, frequency of use, number 
of subscriptions purchased, etc). EPA will issue additional direction 
in the form of official manufacturer guidance to further specify the 
process for submitting reports to the Administrator.
    In addition, EPA is proposing a provision that requires OEMs to 
launch Web sites that meet the following performance criteria:
    (1) OEM Web sites shall possess sufficient server capacity to allow 
ready access by all users and have sufficient downloading capacity to 
assure that all users may obtain needed information without undue 
delay;
    (2) Broken Web links shall be corrected or deleted weekly.
    (3) Web site navigation does not require a user to return to the 
OEM home page or a search engine in order to access a different portion 
of the site.
    (4) It is also proposed that any manufacturer-specific acronym or 
abbreviation shall be defined in a glossary webpage which, at a 
minimum, is hyperlinked by each webpage that uses such acronyms and 
abbreviations. OEMs may request Administrator approval to use alternate 
methods to define such acronyms and abbreviations. The Administrator 
shall approve such methods if the motor vehicle manufacturer adequately 
demonstrates that the method provides equivalent or better ease-of-use 
to the Web site user.
    (5) Indicates the minimum hardware and software specifications 
required for satisfactory access to the Web site(s).
d. Structure and Cost of OEM Web Sites
    In addition to the proposed requirements described above, EPA is 
proposing that OEMs establish a three-tiered approach for the access to 
their Web-based service information. These three tiers are proposed to 
include, but are not limited to short-term, mid-term, and long-term 
access to the required information.
(1) Short-Term Access
    OEMs shall provide short-term access for a period of 24-72 hours 
whereby an aftermarket service provider will be able to access that 
OEM's Web site, search for the information they need, and purchase and/
or print it for a set fee.
(2) Mid-Term Access
    OEMs shall provide mid-term access for a period of 30 days whereby 
an aftermarket service provider will be able to access that OEM's Web 
site, search for the information they need, and purchase and/or print 
it for a set fee.
(3) Long-Term Access
    OEMs shall provide long-term access for a period of 365 days 
whereby an aftermarket service provider will be able to access that 
OEM's Web site, search for the information they need, and purchase and/
or print it for a set fee.
    In addition, for each of the tiers, we propose that OEMs make their 
entire site accessible for the respective period of time and price. In 
other words, we propose that an OEM may not limit any or all of the 
tiers to just one make or one model.
    EPA finalized the three-tiered information access approach in our 
June 2003 rulemaking to accommodate the wide variety of ways in which 
EPA believes aftermarket service providers utilize service information. 
On the under 14,000 side, aftermarket technicians approach the service 
of vehicles anywhere from servicing any make or model that comes into 
their shops to specializing in one particular manufacturer. In 
addition, EPA believes that there are other parties such as ``do-it-
yourself'' mechanics or Inspection/Maintenance programs that may be 
interested in accessing such OEM web-sites. In addition, aftermarket 
service providers for vehicles below 14,000 pounds also relay on third 
party information consolidation entities such as Mitchell or All Data 
to supplement OEM-specific information. These factors, in addition to 
the fact that there are approximately 25ish (check this number) light-
duty vehicle manufacturers, led EPA to the conclusion that a tiered 
approach to Web site access was necessary to ensure maximum 
availability to the aftermarket. EPA requests comment on the nature of 
aftermarket service for the heavy-duty above 14,000 pound industry and 
the need for a tiered approach to information availability.
    Today's action also proposes that, prior to the official launch of 
OEM Web sites, each OEM will be required to present to the 
Administrator a specific outline of what will be charged for access to 
each of the tiers. We are further proposing that OEMs must justify 
these charges, and submit to the Administrator information on the 
following parameters, which include but are not limited to, the 
following:
    (1) The price the manufacturer currently charges their branded 
dealers for service information. At a minimum, this must include the 
direct price charged that is identified exclusively as being for 
service information, not including any payment that is incorporated in 
other fees paid by a dealer, such as franchise fees. In addition, we 
propose that the OEM must describe the information that is provided to 
dealers, including the nature of the information (e.g., the complete 
service manual), etc.; whether dealers have the option of purchasing 
less than all of the available information, or if purchase of all 
information is mandatory; the number of branded dealers who currently 
pay for this service information; and whether this information is made 
available to any persons at a reduced or no cost, and if so, 
identification of these persons and the reason they receive the 
information at a reduced cost.
    (2) The price the manufacturer currently charges persons other than 
branded dealers for service information. The OEM must describe the 
information that is provided, including the nature of the information 
(e.g., the complete service manual, emissions control service manual), 
etc.; and the number of persons other than branded dealers to whom the 
information is supplied.
    (3) The estimated number of persons to whom the manufacturer would 
be expected to provide the service information following implementation 
of today's requirements. If the manufacturer is proposing a fee 
structure with different access periods (e.g., daily, monthly and 
annual periods), the manufacturer must estimate the number of users who 
would be expected to subscribe for the different access periods.
    A complete list of the proposed criteria for establishing 
reasonable cost can be found in the proposed regulatory language for 
this final rule. We are also proposing that, subsequent to the launch 
of the OEM Web sites, OEMs would be required to notify the 
Administrator upon the increase in price of any one or all of the tiers 
of twenty percent or more accounting for inflation or that sets the 
charge for end-user access over the established price guidelines 
discussed above, including a justification based on the criteria for 
reasonable cost as established by this regulation.
    Throughout the history of the current service information 
regulations, the price of service information and how price impacts the 
availability of service information has been a source of significant 
debate and discussion. In looking at the legislative history that led 
to the inclusion of the service information mandate in the Clean Air 
Act Amendments of 1990, it is clear that Congress did not intend for 
the pricing of information to be an artificial barrier

[[Page 3269]]

to access. Further, Congress did not intend for information access 
charges to become a profit center for OEMs. However, EPA has 
interpreted that Congress did intend for OEMs to be able to recover 
reasonable costs for making information available. Since the initial 
implementation of the service information requirements beginning with 
original 1995 final rulemaking, EPA has continued to refine the 
provisions regulating the cost of service to try to balance the 
Congressional intent while understanding that OEMs should be able to 
recover reasonable costs for making the required information available 
to the aftermarket. In fact, the relatively prescriptive nature of some 
of the requirements stem directly from instances on the light-duty side 
where, in the past, we believe some manufacturers deliberately priced 
access to information in such a way that effectively made it 
unavailable to the aftermarket. The provisions being proposed today 
regarding the pricing of service information reflect many years of 
implementation experience, debate, and discussion on the light-duty 
side and EPA specifically requests comment from heavy-duty aftermarket 
service providers on current state of pricing of OEM heavy-duty service 
information and what else EPA should consider for heavy-duty that might 
be different from light-duty.
e. Hyperlinking to and From OEM Web Sites
    Today's action proposes a provision that requires OEMs to allow 
direct simple hyperlinking to their Web sites from government Web sites 
and from all automotive-related Web sites, such as aftermarket service 
providers, educational institutions, and automotive associations.
f. Administrator Access to OEM Web Sites
    Today's action proposes a provision that requires that the 
Administrator shall have access to each OEM Web site at no charge to 
the Agency. The Administrator shall have access to the site, reports, 
records and other information as provided by sections 114 and 208 of 
the Clean Air Act and other provisions of law.
g. Other Media
    We are proposing a provision which would require OEMs to make 
available for ordering the required information in some format approved 
by the Administrator directly from their Web site after the proposed 
full-text window of 15 years has expired. It is proposed that each OEM 
shall index their available information with a title that adequately 
describes the contents of the document to which it refers. In the 
alternate, OEMs may allow for the ordering of information directly from 
their Web site, or from a Web site hyperlinked to the OEM Web site. We 
also propose that OEMs be required to list a phone number and address 
where aftermarket service providers can call or write to obtain the 
desired information. We also propose that OEMs must also provide the 
price of each item listed, as well as the price of items ordered on a 
subscription basis. To the extent that any additional information is 
added or changed for these model years, OEMs shall update the index as 
appropriate. OEMs will be responsible for ensuring that their 
information distributors do so within one regular business day of 
received the order. Items are less than 20 pages (e.g. technical 
service bulletins) shall be faxed to the requestor and distributors are 
required to deliver the information overnight if requested and paid for 
by the ordering party.
h. Small Volume Provisions for OEM Web Sites
    In the July 2003 final rulemaking, EPA finalized a provision to 
provide flexibility for small volume OEMs. In particular, EPA finalized 
a provision that requires OEMs who are issued certificates of 
conformity with total annual sales of less than one thousand vehicles 
are be exempt from the full-text Internet requirements, provided they 
present to the Administrator and obtain approval for an alternative 
method by which emissions-related information can be obtained by the 
aftermarket or other interested parties. EPA also finalized a provision 
giving OEMs with total annual sales of less than five thousand vehicles 
an additional 12 months to launch their full-text Web sites.
    These small-volume flexibilities are limited to the distribution 
and availability of service information via the World Wide Web under 
paragraph (4) of the regulations. All OEMs, regardless of volume, must 
comply with all other provisions as finalized in this rulemaking. EPA 
is requesting comment on the existence of small volume OEMs in the 
heavy-duty arena and the need for any provisions relating to small 
volume OEMs.
3. What Provisions Are Being Proposed for Service Information for Third 
Party Information Providers?
    The nature of the light-duty aftermarket service industry is such 
that they rely to a great extent on consolidated service information 
that is development by third party information providers such as 
Mitchell and All-data. Third-party information providers will license 
OEM service information and consolidate that information for sale to 
the aftermarket. In the June 2003 final rule, EPA finalized a provision 
that will require OEMs who currently have, or in the future engage in, 
licensing or business arrangements with third party information 
providers, as defined in the regulations, to provide information to 
those parties in an electronic format in English that utilizes non-
proprietary software. Further, EPA required that any OEM licensing or 
business arrangements with third party information providers are 
subject to fair and reasonable cost requirements. Lastly, we expect 
that OEMs will develop pricing structures for access to this 
information that make it affordable to any third party information 
providers with which they do business. EPA proposes to extend these 
provisions to the heavy-duty vehicle and engine manufacturers beginning 
with the 2010 model year.
    However, EPA is specifically requesting comment on what role third-
party consolidated information plays in the heavy-duty aftermarket. 
Further, EPA requests comment on the need for these, or additional 
provisions, related to third-party information providers.
4. What Requirements are Being Proposed for the Availability of 
Training Information?
a. Purchase of Training Materials for OEM Web Sites
    In the light-duty service information final rule, EPA finalized two 
provisions for access to OEM emissions-related training. First, OEMs 
are required to make available for purchase on their Web sites the 
following items: Training manuals, training videos, and interactive, 
multimedia CD's or similar training tools available to franchised 
dealerships. Second, we finalized a provision that OEMs who transmit 
emissions-related training via satellite or the Internet must tape 
these transmissions and make them available for purchase on their Web 
sites within 30 days after the first transmission to franchised 
dealerships. Further, all of the items included in this provision must 
be shipped within 24 hours of the order being placed and are to be made 
available at a reasonable price. We also finalized a provision that 
will allow for an exception to the 24 hour shipping requirement in 
those circumstances where orders exceed supply and additional time is 
needed by the distributor to reproduce the item being ordered. For 
subsequent model years,

[[Page 3270]]

the required information must be made available for purchase within 
three months of model introduction, and then be made available at the 
same time it is made available to franchised dealerships.
    EPA is proposing to extend these provisions to the heavy-duty 
industry and requests comment on the need to so or to develop other 
provisions pertaining to the availability of training information for 
the heavy-duty aftermarket.
b. Third Party Access to OEM Training Material
    In the light-duty final rule, we also finalized a provision that 
requires OEMs who utilize Internet and satellite transmissions to 
present emissions-related training to their dealerships to make these 
same transmissions available to third party training providers. In this 
way, we believe we are providing at least one opportunity for 
aftermarket technicians to receive similar emissions-related training 
information as provided to dealerships, thus furthering the goals and 
letter of section 202(m)(5). This requirement only requires OEMs to 
provide the same information to legitimate aftermarket training 
providers as is provided to dealerships and aftermarket service 
providers. It is not a requirement to license OEM copyrighted materials 
to these entities.
    OEMs may take reasonable steps to protect their copyright to the 
extent some or all of this material may be copyrighted and may refuse 
to do business with any party that does not agree to such steps. 
However, we do expect OEMs to use fair business practices in its 
dealings with these third parties, in keeping with the ``fair and 
reasonable price'' requirements in these regulations. OEMs may not 
charge unreasonable up-front fees for access to these transmissions, 
but OEMs may require a royalty, percentage or other arranged fee based 
limits of on a per-use or enrollment subscription basis.
    EPA requests comment on the need to expand the light-duty 
requirements to the heavy-duty sector. EPA also requests comments on 
any additional provisions it should consider to ensure that heavy-duty 
aftermarket service providers and trainers have sufficient access to 
OEM training information at a fair and reasonable price. EPA also 
requests comments on the types of training that is currently 
development by heavy-duty OEMs and what processes may already be in 
place for availability to the aftermarket.
5. What Requirements Are Being Proposed for Reprogramming of Vehicles?
    The 2003 final rule required that light-duty OEMs comply with SAE 
J2534, ``Recommended Practice for Pass-Thru Vehicle Programming''. EPA 
understands that the heavy-duty industry has a similar standard in 
place that is similar to SAE J2534 specification for reprogramming. 
Therefore, today's action proposes two options for pass-thru 
reprogramming. We are proposing that heavy-duty OEMs comply with SAE 
J2534 beginning with 2010 model year. In the alternate, heavy-duty OEMs 
may comply with the Technology and Maintenance Council's Recommended 
Practice RP1210a, ``Windows Communication API,'' July 1999 beginning in 
the 2010 model year. We will also propose a provision that will require 
that reprogramming information be made available within 3 months of 
vehicle introduction for new models.
6. What Requirements are Being Proposed for the Availability of 
Enhanced Information for Scan Tools for Equipment and Tool Companies?
a. Description of Information That Must Be Provided
    Today's action proposes a provision that requires OEMs to make 
available to equipment and tool companies all generic and enhanced 
information, including bi-directional control and data stream 
information. In addition, it is proposed that OEMs must make available 
the following information.
    (i) The physical hardware requirements for data communication (e.g. 
system voltage requirements, cable terminals/pins, connections such as 
RS232 or USB, wires, etc.).
    (ii) ECU data communication (e.g. serial data protocols, 
transmission speed or baud rate, bit timing requirements, etc.).
    (iii) Information on the application physical interface (API) or 
layers. (i.e., processing algorithms or software design descriptions 
for procedures such as connection, initialization, and termination).
    (iv) Vehicle application information or any other related service 
information such as special pins and voltages or additional vehicle 
connectors that require enablement and specifications for the 
enablement.
    (v) Information that describes which interfaces, or combinations of 
interfaces, from each of the categories as described in paragraphs 
(g)(12)(vii)(A) through (D) of the regulatory language.
b. Distribution of Enhanced Diagnostic Information
    Today's action proposes a provision that will require the above 
information for generic and enhanced diagnostic information be provided 
to aftermarket tool and equipment companies with whom appropriate 
licensing, contractual, and confidentiality agreements have been 
arranged. This information shall be made available in electronic format 
using common document formats such as Microsoft Excel, Adobe Acrobat, 
Microsoft Word, etc. Further, any OEM licensing or business 
arrangements with equipment and tool companies are subject to a fair 
and reasonable cost determination.
    7. What Requirements Are Being Proposed for the Availability of 
OEM-Specific Diagnostic Scan Tools and Other Special Tools?
a. Availability of OEM-Specific Diagnostic Scan Tools
    Today's action proposes a provision that OEMs must make available 
for sale to interested parties the same OEM-specific scan tools that 
are available to franchised dealerships, except as discussed below. It 
is proposed that these tools shall be made available at a fair and 
reasonable price. It is also proposed, that these tools shall also be 
made available in a timely fashion either through the OEM Web site or 
through an OEM-designated intermediary.
b. Decontenting of OEM-Specific Diagnostic Scan Tools
    Today's action proposes a provision that requires OEMs who opt to 
remove non-emissions related content from their OEM-specific scan tools 
and sell them to the persons specified in paragraph (g)(2)(i) and 
(f)(2)(i) of the regulatory language for this final rule shall adjust 
the cost of the tool accordingly lower to reflect the decreased value 
of the scan tool. It is proposed that all emissions-related content 
that remains in the OEM-specific tool shall be identical to the 
information that is contained in the complete version of the OEM-
specific tool. Any OEM who wishes to implement this option must request 
approval from the Administrator prior to the introduction of the tool 
into commerce.
c. Availability of Special Tools
    The 2003 final rule precluded light-duty OEMs from using special 
tools to extinguish the malfunction indicator light (MIL) beginning 
with model year 2004. For model years 1994 through 2003, the final rule 
required OEMs who

[[Page 3271]]

currently require such tools to extinguish the MIL must release the 
necessary information to equipment and tool companies to design a 
comparable generic tool. We also required that this information shall 
be made available no later than one month following the effective date 
of the Final Rule. EPA requests comment on this or other special tools 
that may be unique to the heavy-duty industry and on the need for 
provisions covering these tools.
8. Which Reference Materials are Being Proposed for Incorporation by 
Reference?
    Today's action will finalize a provision requiring that OEMs comply 
with the following SAE Recommended Practices.
    (1) SAE Recommended Practice J2403 (October 1998), ``Medium/Heavy-
Duty EE Systems Diagnosis Nomenclature'' beginning with the 2010 model 
year.
    (2) SAE Recommended Practice J2534 (February, 2002), ``Recommended 
Practice for Pass-Thru Vehicle Reprogramming''. EPA will require that 
OEMs comply with SAE J2534 beginning with the 2010 model year.
    (3) SAE Recommended Practice J1939-73.
    (4) ISO/DIS 15031-5 April 30, 2002.

V. What Are the Emissions Reductions Associated With the Proposed OBD 
Requirements?

    In the 2007HD highway rule, we estimated the emissions reductions 
we expected to occur as a result of the emissions standards being made 
final in the rule. Since the OBD requirements contained in today's 
proposal are considered by EPA to be an important element of the 2007HD 
highway program and its ultimate success, rather than a new element 
being included as an addition to that program, we are not estimating 
emissions reductions associated with today's proposal. Instead, we 
consider the new 2007/2010 tailpipe emissions standards and fuel 
standards to be the drivers of emissions reductions and HDOBD to be 
part of the assurance we all have that those emissions reductions are 
indeed realized. Therefore, this analysis presents the emissions 
reductions estimated for the 2007HD highway program. Inherent in those 
estimates is an understanding that, while emissions control systems 
sometimes malfunction, they presumably are repaired in a timely manner. 
Today's proposed OBD requirements would provide substantial tools to 
assure that our presumption will be realized by helping to ensure that 
emission control systems continue to operate properly throughout their 
life. We believe that the OBD requirements proposed today would lead to 
more repairs of malfunctioning or deteriorating emission control 
systems, and may also lead to emission control systems that are more 
robust throughout the life of the engine and less likely to trigger 
illumination of MILs. The requirements would therefore provide greater 
assurance that the emission reductions expected from the Clean Diesel 
Trucks and Buses program will actually occur. Viewed from another 
perspective, while the OBD requirements would not increase the emission 
reductions that we estimated for the 2007HD highway rule, they would be 
expected to lead to actual emission reductions in-use compared with a 
program with no OBD system.
    The costs associated with HDOBD were not fully estimated in the 
2007HD highway rule. Those costs are more fully considered in section 
VI of this preamble. These newly developed HDOBD costs are added to 
those costs estimated for the 2007/2010 standards and a new set of 
costs for those standards are presented in section VII. Section VII 
also calculates a new set of costs per ton associated with the 2007/
2010 standards which include the previously estimated costs and 
emissions reductions for the 2007/2010 standards and the newly 
estimated costs associated with today's HDOBD proposal.
    Here we present the emission benefits we anticipate from heavy-duty 
vehicles as a result of our 2007/2010 NOX, PM, and NMHC 
emission standards for heavy-duty engines. The graphs and tables that 
follow illustrate the Agency's projection of future emissions from 
heavy-duty vehicles for each pollutant. The baseline case represents 
future emissions from heavy-duty vehicles at present standards 
(including the MY2004 standards). The controlled case represents the 
future emissions from heavy-duty vehicles once the new 2007/2010 
standards are implemented. A detailed analysis of the emissions 
reductions associated with the 2007/2010 HD highway standards is 
contained in the Regulatory Impact Analysis for that final rule.\70\ 
The results of that analysis are presented in Table V.A-1 and in 
Figures V.A-1 through V.A-3.
---------------------------------------------------------------------------

    \70\ Regulatory Impact Analysis: Heavy-Duty Engine and Vehicle 
Standards and Highway Diesel Fuel Sulfur Control Requirements; 
EPA420-R-00-026; December 2000.

  Table V.A-1.--Annual Emissions Reductions Associated With the 2007HD
                             Highway Program
                          [thousand short tons]
------------------------------------------------------------------------
                     Year                        NOX       PM      NMHC
------------------------------------------------------------------------
2007.........................................       58       11        2
2010.........................................      419       36       21
2015.........................................    1,260       61       54
2020.........................................    1,820       82       83
2030.........................................    2,570      109      115
------------------------------------------------------------------------


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[[Page 3273]]

[GRAPHIC] [TIFF OMITTED] TP24JA07.003

BILLING CODE 6560-50-C
    There were additional estimated emissions reductions associated 
with the 2007HD highway rule--namely CO, SOX, and air 
toxics. We have not presented those additional emissions reductions 
here since, while HDOBD will identify malfunctions and hasten their 
repair with the result of reducing all emissions constituents, these 
additional emissions are not those specifically targeted by OBD 
systems.

VI. What Are the Costs Associated With the Proposed OBD Requirements?

    Estimated engine costs are broken into variable costs and fixed 
costs. Variable costs are those costs associated with any new hardware 
required to meet the proposed requirements, the associated assembly 
time to install that hardware, and the increased warranty costs 
associated with the new hardware. Variable costs are additionally 
marked up to account for both manufacturer and dealer overhead and 
carrying costs. The manufacturer's carrying cost was estimated to be 
four percent of the direct costs to account for the capital cost of the 
extra inventory and the incremental costs of insurance, handling, and 
storage. The dealer's carrying cost was estimated to be three percent 
of their direct costs to account for the cost of capital tied up in 
inventory. We adopted this same approach to markups in the 2007HD 
highway rule and our more recent Nonroad Tier 4 rule based on industry 
input.
    Fixed costs considered here are those for research and development 
(R&D), certification, and production evaluation testing. The fixed 
costs for engine R&D are estimated to be incurred over the four-year 
period preceding introduction of the engine. The fixed costs for 
certification include costs associated with demonstration testing of 
OBD parent engines including the ``limit'' parts used to demonstrate 
detection of malfunctions at or near the applicable OBD thresholds, and 
generation of certification documentation. Production evaluation 
testing includes testing real world products for standardization 
features, monitor function, and performance ratios. The certification 
costs are estimated to be incurred one year preceding introduction of 
the engine while the production evaluation testing is estimated to 
occur in the same year as introduction.
    The details of our cost analysis are contained in the technical 
support document which can be found in the docket for this rule.\71\ We 
have only summarized the results of that analysis here and point the 
reader to the technical support document for details. We request 
comment on all aspects of our cost analysis.
---------------------------------------------------------------------------

    \71\ Draft Technical Support Document, HDOBD NPRM, EPA420-D-06-
006, Docket ID EPA-HQ-OAR-2005-0047-0008.
---------------------------------------------------------------------------

A. Variable Costs for Engines Used in Vehicles Over 14,000 Pounds

    The variable costs we have estimated represent those costs 
associated with various sensors that we believe would have to be added 
to the engine to provide the required OBD monitoring capability. For 
the 2010 model year, we believe that upgraded computers and the new 
sensors needed for OBD would result in costs to the buyer of $40 and 
$50 for diesel and gasoline engines, respectively. For the 2013 model 
year, we have included costs associated with the dedicated MIL and its 
wiring resulting in a hardware cost to the buyer of $50 and $60 for 
both diesel and gasoline engines, respectively. By multiplying these 
costs per engine by the projected annual sales we get annual costs of 
around $40-50 million for diesel engines and $3-4 million for gasoline 
engines, depending on sales. The 30 year net present value of the 
annual variable costs would be $666 million and $352 million at a three 
percent and a seven percent discount rate, respectively. These costs 
are summarized in Table VI.A-1.

[[Page 3274]]



   Table VI.A-1.--OBD Variable Costs for Engines Used in Vehicles Over
                              14,000 Pounds
     [All costs in $millions except per engine costs; 2004 dollars]
------------------------------------------------------------------------
                                      Diesel      Gasoline      Total
------------------------------------------------------------------------
Cost per engine (2010-2012)......          $40          $50          n/a
Cost per engine (2013+)..........           50           60          n/a
Annual Variable Costs in 2010 \a\           14            1          $15
Annual Variable Costs in 2013 \a\           38            3           40
Annual Variable Costs in 2030 \a\           48            4           52
30 year NPV at a 3% discount rate          620           47          666
30 year NPV at a 7% discount rate          328           25         352
------------------------------------------------------------------------
\a\ Annual variable costs increase as projected sales increase.

B. Fixed Costs for Engines Used in Vehicles Over 14,000 Pounds

    We have estimated fixed costs for research and development (R&D), 
certification, and production evaluation testing. The R&D costs include 
the costs to develop the computer algorithms required to diagnose 
engine and emission control systems, and the costs for applying the 
developed algorithms to each engine family and to each variant within 
each engine family. R&D costs also include the testing time and effort 
needed to develop and apply the OBD algorithms. The certification costs 
include the costs associated with testing of durability engines (i.e., 
the OBD parent engines), the costs associated with generating the 
``limit'' parts that are required to demonstrate OBD detection at or 
near the applicable emissions thresholds, and the costs associated with 
generating the necessary certification documentation. Production 
evaluation testing costs included the costs associated with the three 
types of production testing: standardization features, monitor 
function, and performance ratios.
    Table VI.B-1 summarizes the R&D, certification, and production 
evaluation testing costs that we have estimated. The R&D costs we have 
estimated were totaled and then spread over the four year period prior 
to implementation of the requirements for which the R&D is conducted. 
By 2013, all of the R&D work would be completed in advance of 100 
percent compliance in 2013; hence, R&D costs are zero by 2013. 
Certification costs are higher in 2013 than in 2010 because 2010 
requires one engine family to comply while 2013 requires all engine 
families to comply. The 30 year net present value of the annual fixed 
costs would be $291 million and $241 million at a three percent and a 
seven percent discount rate, respectively.

                                     Table VI.B-1.--OBD Fixed Costs for Engines Used in Vehicles Over 14,000 Pounds
                                                         [All costs in $millions; 2004 dollars]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Diesel                                    Gasoline
                                                      --------------------------------------------------------------------------------------------------
                                                                    Certification                              Certification
                                                           R&D       & PE testing    Subtotal         R&D       & PE testing    Subtotal        Total
--------------------------------------------------------------------------------------------------------------------------------------------------------
Annual OBD Fixed Costs in given years:
    2010.............................................          $51           $0.2         $52            $0.9          <$0.1          $1           $53
    2013.............................................            0            0.4           0.4           0             <0.1          <0.1           0.4
    2030.............................................            0            3             3             0             <0.1          <0.1           3
30 year NPV at the given discount rate:
    3 percent........................................         $263          $17          $280           $10             $0.3         $10          $291
    7 percent........................................          223           10           232             9              0.2           9           241
--------------------------------------------------------------------------------------------------------------------------------------------------------

C. Total Costs for Engines Used in Vehicles Over 14,000 Pounds

    The total OBD costs for engines used in vehicles over 14,000 pounds 
are summarized in Table VI.C-1. As shown in the table, the 30 year net 
present value cost is estimated at $1 billion and $594 million at a 
three percent and a seven percent discount rate, respectively. These 
costs are much lower than the 30 year net present value costs estimated 
for the 2007HD highway emissions standards which were $25 billion and 
$15 billion at a three percent and a seven percent discount rate, 
respectively, for diesel and gasoline engines. Including the cost for 
the diesel fuel changes resulted in 30 year net present value costs for 
that rule of $70 billion and $42 billion at a three percent and a seven 
percent discount rate, respectively. See section VII for more details 
regarding the cost estimates from the 2007HD highway final rule.

[[Page 3275]]



 Table VI.C-1.--OBD Total Costs for Engines Used in Vehicles Over 14,000
                                 Pounds
                 [All costs in $millions; 2004 dollars]
------------------------------------------------------------------------
                                           Diesel    Gasoline    Total
------------------------------------------------------------------------
                  Annual OBD Total Costs in given years
------------------------------------------------------------------------
2010...................................        $65         $2        $67
2013...................................         38          3         41
2030...................................         51          4         55
------------------------------------------------------------------------
                 30 year NPV at the given discount rate
------------------------------------------------------------------------
3%.....................................        900         57        957
7%.....................................        560         34        594
------------------------------------------------------------------------

D. Costs for Diesel Heavy-Duty Vehicles and Engines Used in Heavy-duty 
Vehicles Under 14,000 Pounds

    The total OBD costs for 8,500 to 14,000 pound diesel applications 
are summarized in Table VI.D-1. As shown in the table, the 30 year net 
present value cost is estimated at $6 million and $5 million at a three 
percent and a seven percent discount rate, respectively. These costs 
represent the incremental costs of the proposed additional OBD 
requirements, as compared to our current OBD requirements, for 8,500 to 
14,000 pound diesel applications and do not represent the total costs 
for 8,500 to 14,000 pound diesel OBD. We are proposing no changes to 
the 8,500 to 14,000 pound gasoline requirements so, therefore, have 
estimated no costs for gasoline vehicles. Details behind these 
estimated costs can be found in the technical support document 
contained in the docket for this rule.\72\
---------------------------------------------------------------------------

    \72\ Draft Technical Support Document, HDOBD NPRM, EPA420-D-06-
006, Docket ID EPA-HQ-OAR-2005-0047-0008.

     Table VI.D-1.--Total OBD Costs for 8,500 to 14,000 Pound Diesel
                              Applications
                 [All costs in $millions; 2004 dollars]
------------------------------------------------------------------------
                                           Diesel    Gasoline    Total
------------------------------------------------------------------------
                  Annual OBD Total Costs in given years
------------------------------------------------------------------------
2010...................................       $0.1         $0       $0.1
2013...................................          0          0          0
2030...................................        0.4          0        0.4
------------------------------------------------------------------------
                 30 year NPV at the given discount rate
------------------------------------------------------------------------
3%.....................................          6          0          6
7%.....................................          5          0          5
------------------------------------------------------------------------

VII. What are the Updated Annual Costs and Costs per Ton Associated 
With the 2007/2010 Heavy-duty Highway Program?

    In the 2007HD highway rule, we estimated the costs we expected to 
occur as a result of the emissions standards being made final in that 
rule. As noted in section V, we consider the OBD requirements contained 
in today's proposal to be an important element of the 2007HD highway 
program and its ultimate success and not a new element being included 
as an addition to that program. In fact, without the proposed OBD 
requirements we would not expect the emissions reductions associated 
with the 2007/2010 standards to be fully realized because emissions 
control systems cannot be expected to operate without some need for 
repair which, absent OBD, may well never be done. However, as noted in 
section VI, because we did not include an OBD program in the 2007HD 
highway program, we did not estimate OBD related costs at that time. We 
have now done so and those costs are presented in section VI.
    Here we present the OBD costs as part of the greater 2007HD highway 
program. To do this, we present both the costs developed for that 
program and the additional OBD costs presented in section VI. We also 
calculate a new set of costs per ton associated with the 2007/2010 
standards which include the previously estimated costs and emissions 
reductions for the 2007/2010 standards and the newly estimated costs 
associated with today's HDOBD proposal.
    Note that the costs estimates associated with the 2007HD highway 
program were done using 1999 dollars. We have estimated OBD costs in 
2004 dollars. We consulted the Producer Price Index (PPI) for ``Motor 
vehicle parts manufacturing-new exhaust system parts'' developed by the 
Bureau of Labor Statistics and found that the PPI for such parts had 
actually decreased from 1999 to 2004.\73\ This suggests that the cost 
to produce exhaust system parts has decreased since 1999. For clarity, 
rather than adjusting downward the 2007HD highway program costs from 
1999 dollars, or adjusting upward the OBD costs from 2004 dollars, we 
have chosen to present the 2007HD highway rule costs as they were 
presented in that final rule alongside the OBD costs presented in 
section VI. In short, we are ignoring the PPI effect in the following 
tables.
---------------------------------------------------------------------------

    \73\ See www.bls.gov/ppi; All other motor vehicle parts mfg; 
Exhaust system parts, new; series ID PCU3363993363993; Base date 
8812.
---------------------------------------------------------------------------

A. Updated 2007 Heavy-Duty Highway Rule Costs Including OBD

    Table VII.A-1 shows the 2007HD highway program costs along with the 
estimated OBD related costs.

   Table VII.A-1.--Updated 2007HD Highway Program Costs, Including New OBD-Related Costs, Net Present Value of
                                      Annual Costs for the Years 2006-2035
                                            [All costs in $millions]
----------------------------------------------------------------------------------------------------------------
                                                2007 HD Highway Final Rule
                                   ----------------------------------------------------                Updated
                                                   Gasoline                             Proposed HD     total
           Discount rate               Diesel      engine &   Diesel fuel    Original       OBD        program
                                       engine      vehicle       costs     total costs                  costs
                                       costs        costs
----------------------------------------------------------------------------------------------------------------
3 percent.........................      $23,721       $1,514      $45,191      $70,427         $963      $71,389
7 percent.........................       14,369          877       26,957       42,203          599       42,802
----------------------------------------------------------------------------------------------------------------


[[Page 3276]]

B. Updated 2007 Heavy-Duty Highway Rule Costs per Ton Including OBD

    Table VII.B-1 shows the 2007HD highway program costs per ton of 
pollutant reduced. These numbers are straight from the 2007HD highway 
final rule which contains the details regarding the split between 
NOX+NMHC and PM related costs.

         Table VII.B-1.--Original 2007HD Highway Program Costs, Emissions Reductions, and $/Ton Reduced
                        [Net present values are for annual costs for the years 2006-2035]
----------------------------------------------------------------------------------------------------------------
                                                                    30 year NPV     30 year NPV
             Discount rate                      Pollutant              cost          reduction         $/ton
                                                                    ($billions)   (million tons)
----------------------------------------------------------------------------------------------------------------
3 percent.............................  NOX+NMHC................            54.6            30.6           1,780
                                        PM......................            16.0             1.4          11,790
7 percent.............................  NOX+NMHC................            34.9            16.2           2,150
                                        PM......................            10.3             0.8          13,610
----------------------------------------------------------------------------------------------------------------

    Table VII.B-2 shows the updated 2007HD highway program costs per 
ton of pollutant reduced once the new OBD costs have been included. For 
the split between NOX+NMHC and PM-related OBD costs, we have 
used a 50/50 allocation. As shown in Table VII.B-2, the OBD costs 
associated with the proposed OBD requirements have little impact on the 
overall costs and costs per ton of emissions reduced within the context 
of the 2007HD highway program.

   Table VII.B-2.--Updated 2007HD Highway Program Costs, Emissions Reductions, and $/ton Reduced Including OBD
                                                  Related Costs
                        [Net present values are for annual costs for the years 2006-2035]
----------------------------------------------------------------------------------------------------------------
                                                                    30 year NPV     30 year NPV
             Discount rate                      Pollutant              cost          reduction         $/ton
                                                                    ($billions)   (million tons)
----------------------------------------------------------------------------------------------------------------
3 percent.............................  NOX+NMHC................            55.1            30.6           1,800
                                        PM......................            16.5             1.4          12,210
7 percent.............................  NOX+NMHC................            35.2            16.2           2,170
                                        PM......................            10.6             0.8          14,130
----------------------------------------------------------------------------------------------------------------

VIII. What Are the Requirements for Engine Manufacturers?

A. Documentation Requirements

    The OBD system certification requirements would require 
manufacturers to submit OBD system documentation that represents each 
engine family. The certification documentation would be required to 
contain all of the information needed to determine if the OBD system 
meets the proposed OBD requirements. The proposed regulation lists the 
information that would be required as part of the certification 
package. If any of the information in the certification package is the 
same for all of a manufacturer's engine families (e.g., the OBD system 
general description), the manufacturer would only be required to submit 
one set of documents each model year for such items that would cover 
all of its engine families.
    While the majority of the proposed OBD requirements would apply to 
the engine and be incorporated by design into the engine control module 
by the engine manufacturer, a portion of the proposed OBD requirements 
would apply to the vehicle and not be self-contained within the engine. 
Examples include the proposed requirements to have a MIL in the 
instrument cluster and a diagnostic connector in the cab compartment. 
As is currently done by the engine manufacturers, a build specification 
is provided to vehicle manufacturers detailing mechanical and 
electrical specifications that must be adhered to for proper 
installation and use of the engine (and to maintain compliance with 
emissions standards). We expect engine manufacturers would continue to 
follow this practice so that the vehicle manufacturer would be able to 
maintain compliance with the proposed OBD regulations. Installation 
specifications would be expected to include instructions regarding the 
location, color, and display icon of the MIL (as well as electrical 
connections to ensure proper illumination), location and type of 
diagnostic connector, and electronic VIN access. During the 
certification process, in addition to submitting the details of all of 
the diagnostic strategies and other information required, engine 
manufacturers would be required to submit a copy of the OBD-relevant 
installation specifications provided to vehicle manufacturers and a 
description of the method used by the engine manufacturer to ensure 
vehicle manufacturers adhere to the provided installation 
specifications (e.g., required audit procedures or signed agreements to 
adhere to the requirements). We are requiring that this information be 
submitted to us to provide a reasonable level of verification that the 
proposed OBD requirements would indeed be satisfied. In summary, engine 
manufacturers would be responsible for submitting a certification 
package that includes:
     A detailed description of all OBD monitors, including 
monitors on signals or messages coming from other modules upon which 
the engine control unit relies to perform other OBD monitors; and,
     A copy of the OBD-relevant installation specifications 
provided to vehicle manufacturers/chassis builders and the method used 
to reasonably ensure compliance with those specifications.
    As was discussed in the context of our implementation schedule (see 
section II.G.1), the proposed regulations would allow engine 
manufacturers to establish

[[Page 3277]]

OBD groups consisting of more than one engine family with each having 
similar OBD systems. The manufacturer could then submit only one set of 
representative OBD information from each OBD group. We anticipate that 
the representative information would normally consist of an application 
from a single representative engine rating within each OBD group. In 
selecting the engine ratings to represent each OBD group, consideration 
should be given to the exhaust emission control components for all 
engine families and ratings within an OBD group. For example, if one 
engine family within an OBD group has additional emission control 
devices relative to another family in the group (e.g., the first family 
has a DPF+SCR while the second has only a DPF), the representative 
rating should probably come from the first engine family. Manufacturers 
seeking to consolidate several engine families into one OBD group would 
be required to get approval of the grouping prior to submitting the 
information for certification.
    Two of the most important parts of the certification package would 
be the OBD system description and summary table. The OBD system 
description would include a complete written description for each 
monitoring strategy outlining every step in the decision-making process 
of the monitor, including a general explanation of the monitoring 
conditions and malfunction criteria. This description should include 
graphs, diagrams, and/or other data that would help our compliance 
staff understand how each monitor works and interacts. The OBD summary 
table would include specific parameter values. This table would provide 
a summary of the OBD system specifications, including: the component/
system, the DTC identifying each related malfunction, the monitoring 
strategy, the parameter used to detect a malfunction and the 
malfunction criteria limits against which the parameter is evaluated, 
any secondary parameter values and the operating conditions needed to 
run the monitor, the time required to execute and complete a monitoring 
event for both a pass decision and a fail decision, and the criteria or 
procedure for illuminating the MIL. In these tables, manufacturers 
would be required to use a common set of engineering units to simplify 
and expedite the review process.
    We are also proposing that the manufacturer submit a logic 
flowchart for each monitor that would illustrate the step-by-step 
decision process for determining malfunctions. Additionally, we would 
need any data that supports the criteria used to determine malfunctions 
that cause emissions to exceed the specified malfunction thresholds 
(see Tables II.B-1 and II.C-1). The manufacturer would have to include 
data that demonstrates the probability of misfire detection by the 
misfire monitor over the full engine speed and load operating range 
(for gasoline engines only) or the capability of the misfire monitor to 
correctly identify a ``one cylinder out'' misfire for each cylinder 
(for diesel engines only), a description of all the parameters and 
conditions necessary to begin closed-loop fuel control operation (for 
gasoline engines only), closed-loop EGR control (for diesel engines 
only), closed-loop fuel pressure control (for diesel engines only), and 
closed-loop boost control (for diesel engines only). We would also need 
a listing of all electronic powertrain input and output signals 
(including those not monitored by the OBD system) that identifies which 
signals are monitored by the OBD system, and the emission data from the 
OBD demonstration testing (as described below). Lastly, the 
manufacturer would be expected to provide any other OBD-related 
information necessary to determine the OBD compliance status of the 
manufacturer's product line.

B. Catalyst Aging Procedures

    For purposes of determining the catalyst malfunction criteria for 
diesel NMHC converting catalysts, SCR catalysts, and lean 
NOX catalysts, and for gasoline catalysts, where those 
catalysts are monitored individually, the manufacturer must use a 
catalyst deteriorated to the malfunction criteria using methods 
established by the manufacturer to represent real world catalyst 
deterioration under normal and malfunctioning engine operating 
conditions. For purposes of determining the catalyst malfunction 
criteria for diesel NMHC converting catalysts, SCR catalysts, and lean 
NOX catalysts, and for gasoline catalysts, where those 
catalysts are monitored in combination with other catalysts, the 
manufacturer would have to submit their catalyst system aging and 
monitoring plan to the Administrator as part of their certification 
documentation package. The plan would include the description, emission 
control purpose, and location of each component, the monitoring 
strategy for each component and/or combination of components, and the 
method for determining the applicable malfunction criteria including 
the deterioration/aging process.

C. Demonstration Testing

    While the proposed certification documentation requirements 
discussed above would require manufacturers to submit technical details 
of each monitor (e.g., how each monitor worked, when the monitor would 
run), we would still need some assurance that the manufacturer's OBD 
monitors are indeed calibrated correctly and are able to detect a 
malfunction before an emissions threshold is exceeded. Thus, we are 
proposing that manufacturers conduct certification demonstration 
testing of the major monitors to verify the malfunction threshold 
values. This testing would be required on one to three demonstration 
engines per year. Before receiving a certificate of compliance, the 
manufacturer would be required to submit documentation and emissions 
data demonstrating that the major OBD monitors are able to detect a 
malfunction when emissions exceed the emissions thresholds. On each 
demonstration engine, this testing would consist of the following two 
elements:
     Testing the OBD system with ``threshold'' components 
(i.e., components that are deteriorated or malfunctioning right at the 
threshold required for MIL illumination); and,
     Testing the OBD system with ``worst case'' components. 
This element of the demonstration test would have to be done for the 
DPF and any NOX aftertreatment system only.
    By testing with both threshold components (i.e., the best 
performing malfunctioning components) and with worst case components 
(i.e., the worst performing malfunctioning components), we would be 
better able to verify that the OBD system should perform as expected 
regardless of the level of deterioration of the component. This could 
become increasingly important with new technology aftertreatment 
devices that could be subject to complete failure (such as DPFs) or 
even to tampering by vehicle operators looking to improve fuel economy 
or vehicle performance. We believe that, given the likely combinations 
of emissions control hardware, a diesel engine manufacturer would 
likely need to conduct 8 to 10 emissions tests per demonstration engine 
to satisfy these requirements and a gasoline engine manufacturer would 
likely need to conduct five to seven emissions tests per demonstration 
engine.\74\
---------------------------------------------------------------------------

    \74\ For diesel engines these would include: the fuel system; 
misfire (HCCI engines); EGR, turbo boost control, DPF, 
NOX adsorber or SCR system, NMHC catalyst, exhaust gas 
sensors, VVT, and possible other emissions controls (see section 
II.D.5). For gasoline engines these would include: the fuel system, 
misfire, EGR, cold start strategy, secondary air system, catalyst, 
exhaust gas sensors, VVT, and possible other emissions controls (see 
section II.D.5). Some of these may require more than one emissions 
test while others may not require any due to the use of a functional 
monitor rather than an emissions threshold monitor.

---------------------------------------------------------------------------

[[Page 3278]]

1. Selection of Test Engines
    To minimize the test burden on manufacturers, we are proposing that 
this testing be done on only one to three demonstration engines per 
year per manufacturer rather than requiring that all engines be tested. 
Such an approach should still allow us to be reasonably sure that 
manufacturers have calibrated their OBD systems correctly on all of 
their engines. This also spreads the test burden over several years and 
allows manufacturers to better utilize their test cell resources. This 
approach is consistent with our approach to demonstration testing to 
existing emissions standards where a parent engine is chosen to 
represent each engine family and emissions test data for only that 
parent engine are submitted to EPA.\75\
---------------------------------------------------------------------------

    \75\ For over 14,000 pound OBD, we are proposing a different 
definition of a ``parent'' engine than is used for emissions 
certification. This is discussed at length in section II.G.
---------------------------------------------------------------------------

    The number of demonstration engines manufacturers would be required 
to test would be aligned with the phase-in of OBD in the 2010 and 2013 
model years and based on the year and the total number of engine 
families the manufacturer would be certifying for that model year. 
Specifically, for the 2010 model year when a manufacturer is only 
required to implement OBD on a single engine family, demonstration 
testing would be required on only one engine (a single engine rating 
within the one engine family). This would be the OBD parent rating as 
discussed in section II.G. For the 2013 model year, manufacturers would 
be required to conduct demonstration testing on one to three engines 
per year (i.e., one to three OBD parent ratings). The number of parent 
ratings would be chosen depending on the total number of engine 
families certified by the manufacturer. A manufacturer certifying one 
to five engine families in the given year would be required to test one 
demonstration engine. A manufacturer certifying six to ten engine 
families in the given year would be required to test two demonstration 
engines, and a manufacturer certifying more than ten engine families in 
the given year would be required to test three demonstration engines. 
For the 2016 and subsequent model years, we would work closely with 
CARB staff and the manufacturer to determine the parent ratings so that 
the same ratings are not acting as the parents every year. In other 
words, our definitions for the OBD parent ratings as discussed here 
apply only during the years 2010 through 2012 and again for the years 
2013 through 2015.
    Given the difficulty and expense in removing an in-use engine from 
a vehicle for engine dynamometer testing, this demonstration testing 
would likely represent nearly all of the OBD emission testing that 
would ever be done on these engines. Requiring a manufacturer who is 
fully equipped to do such testing, and already has the engines on 
engine dynamometers for emission testing, to test one to three engines 
per year would be a minimal testing burden that provides invaluable 
and, in a practical sense, otherwise unobtainable proof of compliance 
with the OBD emissions thresholds.
    Regarding the selection of which engine ratings would have to be 
demonstrated, manufacturers would be required to submit descriptions of 
all engine families and ratings planned for the upcoming model year. We 
would review the information and make the selection(s) in consultation 
with CARB staff and the manufacturer. For each engine family and 
rating, the information submitted by the manufacturer would need to 
identify engine model(s), power ratings, applicable emissions standards 
or family emissions limits, emissions controls on the engine, and 
projected engine sales volume. Factors that would be used in selecting 
the one to three engine ratings for demonstration testing include, but 
are not limited to, new versus old/carryover engines, emissions control 
system design, possible transition point to more stringent emissions 
standards and/or OBD emissions thresholds, and projected sales volume.
2. Required Testing
    Regarding the actual testing, the manufacturer would be required to 
perform ``single fault'' testing using the applicable test procedure 
and with the appropriate components/systems set at the manufacturer 
defined malfunction criteria limits for the following monitors:
     For diesel engines: Fuel system; misfire; EGR; turbo boost 
control; NMHC catalyst; NOX catalyst/adsorber; DPF; exhaust 
gas sensors; VVT; and any other monitor that would fall within the 
discussion of section II.D.5.
     For gasoline engines: Fuel system; misfire; EGR; cold 
start strategy; secondary air; catalyst; exhaust gas sensors; VVT; and 
any other monitor that would fall within the discussion of section 
II.D.5.
    Such ``single fault'' testing would require that, when performing a 
test for a specific parameter, that parameter must be operating at the 
malfunction criteria limit while all other parameters would be 
operating within normal characteristics (unless the malfunction 
prohibits some other parameter from operating within its normal 
characteristics). Also, the manufacturer would be allowed to use 
computer modifications to cause the specific parameter to operate at 
the malfunction limit provided the manufacturer can demonstrate that 
the computer modifications produce test results equivalent to an 
induced hardware malfunction. Lastly, for each of these testing 
requirements, wherever the manufacturer has established that only a 
functional check is required because no failure or deterioration of the 
specific tested component/system could result in an engine's emissions 
exceeding the applicable emissions thresholds, the manufacturer would 
not be required to perform a demonstration test. In such cases, the 
manufacturer could simply provide the data and/or engineering analysis 
used to determine that only a functional test of the component/system 
was required.
    Manufacturers required to submit data from more than one engine 
rating would be granted some flexibility by allowing the data to be 
collected under less rigorous testing requirements than the official 
FTP or SET certification test. That is, for the possible second and 
third engine ratings required for demonstration testing, manufacturers 
would be allowed to submit data using internal sign-off test procedures 
that are representative of the official FTP or SET in lieu of running 
the official test. Commonly used procedures include the use of engine 
emissions test cells with less rigorous quality control procedures than 
those required for the FTP or SET or the use of forced cool-downs to 
minimize time between tests. Manufacturers would still be liable for 
meeting the OBD emissions thresholds on FTPs and/or SETs conducted in 
full accordance with the Code of Federal Regulations. Nonetheless, this 
latitude would allow them to use some short-cut methods that they have 
developed to assure themselves that the system is calibrated to the 
correct level without incurring the additional testing cost and burden 
of running the official FTP or SET on every demonstration engine.
    For the demonstration engine(s), a manufacturer would be required 
to use an engine(s) aged for a minimum of 125

[[Page 3279]]

hours plus exhaust aftertreatment devices aged to be representative of 
full useful life. Manufacturers would be expected to use, subject to 
approval, an aging process that ensures that deterioration of the 
exhaust aftertreatment devices is stabilized sufficiently such that it 
properly represents the performance of the devices at the end of their 
useful life.
3. Testing Protocol
    We are proposing that the manufacturer be allowed to use any 
applicable test cycle for preconditioning test engines prior to 
conducting each of the emissions tests discussed above. Additional 
preconditioning can be done if the manufacturer has provided data and/
or engineering analyses that demonstrate that additional 
preconditioning is necessary.
    The manufacturer would then set the system or component of interest 
at the criteria limit(s) prior to conducting the applicable 
preconditioning cycle(s). If more than one preconditioning cycle is 
being used, the manufacturer may adjust the system or component of 
interest prior to conducting the subsequent preconditioning cycle. 
However, the manufacturer may not replace, modify, or adjust the system 
or component of interest following the last preconditioning cycle.
    After preconditioning, the test engine would be operated over the 
applicable test cycle to allow for the initial detection of the tested 
system or component malfunction. This test cycle may be omitted from 
the testing protocol if it is unnecessary. If required by the 
designated monitoring strategy, a cold soak may be performed prior to 
conducting this test cycle. The test engine would then be operated over 
the applicable exhaust emission test.
    A manufacturer required to test more than one test engine may use 
internal calibration sign-off test procedures (e.g., forced cool downs, 
less frequently calibrated emission analyzers) instead of official test 
procedures to obtain this emissions test data for all but one of the 
required test engines. However, the manufacturer should use sound 
engineering judgment to ensure that the data generated using such 
alternative test/sign-off procedures are good data because 
manufacturers would still be responsible for meeting the malfunction 
criteria when emissions tests are performed in accordance with official 
test procedures.
    Manufacturers would be allowed to use alternative testing 
protocols, even chassis testing, for demonstration of MIL illumination 
if the engine dynamometer emissions test cycle does not allow all of a 
monitor's enable conditions to be satisfied. Manufacturers wanting to 
do so would be required to demonstrate the technical necessity for 
using their alternative test cycle and that using it demonstrates that 
the MIL would illuminate during in-use operation with the 
malfunctioning component.
4. Evaluation Protocol
    For all demonstration tests on parent engines, we would expect that 
the MIL would activate upon detecting the malfunctioning system or 
component, and that it should occur before the end of the first engine 
start portion of the emissions test. If the MIL were to activate prior 
to emissions exceeding the applicable malfunction criteria, no further 
demonstration would be required. With respect to the misfire monitor 
demonstration test, if the manufacturer has elected to use the minimum 
misfire malfunction criterion of one percent (as is allowed), then no 
further demonstration would be required provided the MIL were to 
illuminate during a test with an implanted misfire of one percent.
    If the MIL does not activate when the system or component being 
tested is set at its malfunction criteria limits, then the criteria 
limits or the OBD system would not be considered acceptable. Retesting 
would be required with more tightly controlled criteria limits (i.e., 
recalibrated limits) and/or another suitable system or component that 
would result in MIL activation. If the criteria limits are 
recalibrated, the manufacturer would be required to confirm that the 
systems and components that were tested prior to recalibration would 
still function properly and as required.
5. Confirmatory Testing
    We may choose to confirmatory test a demonstration engine to verify 
the emissions test data submitted by the manufacturer. Any such 
confirmatory testing would be limited to the engine rating represented 
by the demonstration engine(s) (i.e., the parent engine(s)). To do so, 
we, or our designee, would install appropriately deteriorated or 
malfunctioning components (or simulate a deteriorated or malfunctioning 
component) in an otherwise properly functioning engine of the same 
engine family and rating as the demonstration engine. Such confirmatory 
testing would be done on those OBD monitors for which demonstration 
testing had been conducted as described in this section. The 
manufacturer would be required to make available, upon Administrator 
request, a test engine and all test equipment--e.g., malfunction 
simulators, deteriorated components--necessary to duplicate the 
manufacturer's testing.

D. Deficiencies

    Our under 14,000 pound OBD requirements have contained a deficiency 
provision for years. The OBD deficiency provision was first introduced 
on March 23, 1995 (60 FR 15242), and was revised on December 22, 1998 
(63 FR 70681). Consistent with that provision, we are proposing a 
deficiency provision for over 14,000 pound OBD. We believe that, like 
has occurred and even still occurs with under 14,000 pound OBD, some 
manufacturers will encounter unforeseen and generally last minute 
problems with some of their OBD monitoring strategies despite having 
made a good faith effort to comply with the requirements. Therefore, we 
are proposing a provision that would permit certification of an over 
14,000 pound OBD system with ``deficiencies'' in cases where a good 
faith effort to fully comply has been demonstrated. In making 
deficiency determinations, we would consider the extent to which the 
proposed OBD requirements have been satisfied overall based on our 
review of the certification application, the relative performance of 
the given OBD system compared to systems that truly are fully compliant 
with the proposed OBD requirements, and a demonstrated good-faith 
effort on the part of the manufacturer to both meet the proposed 
requirements in full and come into full compliance as expeditiously as 
possible.
    We believe that having the proposed deficiency provision is 
important because it would facilitate OBD implementation by allowing 
for certification of an engine despite having a relatively minor 
shortfall. Note that we do not expect to certify engines with OBD 
systems that have more than one deficiency, or to allow carryover of 
any deficiency to the following model year unless it can be 
demonstrated that correction of the deficiency requires hardware and/or 
software modifications that cannot be accomplished in the time 
available, as determined by the Administrator.\76\ Nonetheless, we 
recognize that there may be situations where more than one deficiency 
is necessary and appropriate, or where carry-over of a deficiency or 
deficiencies for more than one year is necessary and

[[Page 3280]]

appropriate. In such situations, more than one deficiency, or carry-
over for more than one year, may be approved, provided the manufacturer 
has demonstrated an acceptable level of effort toward full OBD 
compliance. Most importantly, the deficiency provisions cannot be used 
as a means to avoid compliance or delay implementation of any OBD 
monitors or as a means to compromise the overall effectiveness of the 
OBD program.
---------------------------------------------------------------------------

    \76\ The CARB HDOBD rulemaking has a provision to charge fees 
associated with OBD deficiencies 13 CCR 1971.1(k)(3), Docket 
ID EPA-HQ-OAR-2005-0047-0006. We have never had and are not 
proposing any such fee provision.
---------------------------------------------------------------------------

    There has often been some confusion by manufacturers regarding what 
CARB has termed ``retroactive'' deficiencies. The CARB rule states 
that, ``During the first 6 months after commencement of normal 
production, manufacturers may request that the Executive Officer grant 
a deficiency and amend an engine's certification to conform to the 
granting of the deficiencies for each aspect of the monitoring system: 
(a) Identified by the manufacturer (during testing required by section 
(l)(2) or any other testing) to be functioning different than the 
certified system or otherwise not meeting the requirements of any 
aspect of section 1971.1; and (b) reported to the Executive Officer.'' 
\77\ We have never had and are not proposing any such retroactive 
deficiency provision. We have regulations in place that govern 
situations, whether they be detected by EPA or by the manufacturer, 
where in-use vehicles or engines are determined to be functioning 
differently than the certified system.\78\ We refer to these 
regulations as our defect reporting requirements and manufacturers are 
required to comply with these regulations, even for situations deemed 
by CARB to be ``retroactive'' deficiencies, unless the defect is 
corrected prior to the sale of engines to an ultimate purchaser. In 
other words, a retroactive deficiency granted by the Executive Officer 
does not preclude a manufacturer from complying with our defect 
reporting requirements.
---------------------------------------------------------------------------

    \77\ See 13 CFR 1971.1(k)(6)), Docket ID EPA-HQ-OAR-
2005-0047-0006.
    \78\ See 40 CFR 85.1903.
---------------------------------------------------------------------------

E. Production Evaluation Testing

    The OBD system is a complex software and hardware system, so there 
are many opportunities for unintended interactions that can result in 
certain elements of the system not working as intended. We have seen 
many such mistakes in the under 14,000 pound arena ranging from OBD 
systems that are unable to communicate any information to a scan tool 
to monitors that are unable to store a DTC and illuminate the MIL. 
While over 14,000 pound heavy-duty vehicles are very different from 
light-duty vehicles in terms of emission controls and OBD monitoring 
strategies, among other things, these types of problems do not depend 
on these differences and, as such, are as likely to occur with over 
14,000 pound OBD as they are with under 14,000 pound OBD. Additionally, 
we believe that there is great value in having manufacturers self-test 
actual production end products that operate on the road, as opposed to 
pre-production products, where errors can be found in individual 
subsystems that may work fine by themselves but not when integrated 
into a complete product (e.g., due to mistakes like improper wiring).
    Therefore, we are proposing that manufacturers self-test a small 
fraction of their product line to verify compliance with the OBD 
requirements. The test requirements are divided into three distinct 
sections with each section representing a test for a different portion 
of the OBD requirements. These three sections being: compliance with 
the applicable SAE and/or ISO standardization requirements; compliance 
with the monitoring requirements for proper DTC storage and MIL 
illumination; and, compliance with the in-use monitoring performance 
ratios.
1. Verification of Standardization Requirements
    An essential part of the OBD system is the requirement for 
standardization. The proposed standardization requirements include 
items as simple as the location and shape of the diagnostic connector 
(where technicians can ``plug in'' a scan tool to the onboard computer) 
to more complex subjects concerning the manner and format in which DTC 
information is accessed by technicians via a ``generic'' scan tool. 
Manufacturers must meet these standardization requirements to 
facilitate the success of the proposed OBD program because they ensure 
consistent access by all repair technicians to the stored information 
in the onboard computer. The need for consistency is even greater when 
considering the potential use of OBD system checks in inspection and 
maintenance (I/M) programs for heavy-duty. Such OBD base I/M checks 
would benefit from having access to the diagnostic information in the 
onboard computer via a single ``generic'' scan tool instead of 
individual tools for every make and model of truck that might be 
inspected. For OBD based inspections to work effectively and 
efficiently, all engines/vehicles must be designed and built to meet 
all of the applicable standardization requirements.
    While we anticipate that the vast majority of vehicles would comply 
with all of the standardization requirements, some problems involving 
the communication between vehicles and ``generic'' scan tools are 
likely to occur in the field. The cause of such problems could range 
from differing interpretations of the existing standardization 
requirements to possible oversights by design engineers or hardware 
inconsistencies or even last-minute production changes on the assembly 
line.
    To minimize the chance for such problems on future over 14,000 
pound trucks, we are proposing that engine manufacturers be required to 
test a sample of production vehicles from the assembly line to verify 
that the vehicles have indeed been designed and built to the required 
specifications for communication with a ``generic'' scan tool. We are 
proposing that manufacturers be required to test complete vehicles to 
ensure that they comply with some of the basic ``generic'' scan tool 
standardization requirements, including those that are essential for 
proper inspection in an I/M setting. Ideally, manufacturers would be 
required to test one vehicle for each truck and engine model 
combination that is introduced into commerce. However, for a large 
engine manufacturer, this can be in the neighborhood of 5,000 to 10,000 
unique combinations making it unreasonable to require testing of every 
combination. Therefore, we are proposing that manufacturers test 10 
such combinations per engine family. Given that a typical engine family 
has roughly five different engine ratings, this works out to testing 
only around two vehicles per engine rating.
    More specifically, manufacturers would be required to test one 
vehicle per software ``version'' released by the manufacturer. With 
proper demonstration, manufacturers would be allowed to group different 
calibrations together to be demonstrated by a common vehicle. Prior to 
acquiring these data, the proposal would require engine manufacturers 
to submit for approval a test plan verifying that the vehicles 
scheduled for testing would be representative of all vehicle 
configurations (e.g., each engine control module variant coupled with 
and without the other available vehicle components that could affect 
scan tool communication such as automatic transmission or hybrid 
powertrain control modules). The plan would have to include details on 
all the different applications and configurations that would be tested.

[[Page 3281]]

    As noted, manufacturers would be required to conduct this testing 
on actual production vehicles, not stand-alone engines. This is 
important since controllers that work properly in a stand alone setting 
(e.g., the engine before it is installed in a vehicle) may have 
interaction problems when installed and attempting to communicate with 
other vehicle controllers (e.g., the transmission controller). In such 
a case, separate testing of the controllers would be blind to the 
problem. Since heavy-duty engine manufacturers are expected to sell the 
same engine (with the same calibration) to various vehicle 
manufacturers who would put them in different final products (e.g., 
with different transmission control modules), the same communication 
problem would be expected in each final product.
    This testing should occur soon enough in the production cycle to 
provide manufacturers with early feedback regarding the existence of 
any problems and time to resolve the problem prior to the entire model 
year's products being introduced into the field. We are proposing that 
the testing be done and the data submitted to us within either three 
months of the start of normal engine production or one month of the 
start of vehicle production, whichever is later.
    To be sure that all manufacturers are testing vehicles to the same 
level of stringency, we are proposing that engine manufacturers submit 
documentation outlining the testing equipment and methods they intend 
to use to perform this testing. We anticipate that engine manufacturers 
and scan tool manufacturers would probably develop a common piece of 
hardware and software that could be used by all engine manufacturers at 
the end of the vehicle assembly line to meet this requirement. Two 
different projects (SAE J1699 and LOC3T) have developed such equipment 
in response to California OBD II requirements.\79\ The equipment is 
currently being used to test 2005 and 2006 model year vehicles under 
14,000 pounds. We believe that similar equipment could be developed for 
vehicles over 14,000 pounds in time for the 2013 model year. Ideally, 
the equipment and the test procedure would verify each and every 
requirement of the communication specifications including the various 
physical layers, message structure, response times, and message 
content. Presumably, any such verification equipment would not replace 
the function of existing ``generic'' scan tools used by repair 
technicians or I/M inspectors. The equipment would likely be custom-
designed and be used for the express purpose of this assembly line 
testing (i.e., it would not include all of the necessary diagnostic 
features needed by repair technicians).
---------------------------------------------------------------------------

    \79\ 13 CCR 1968.2, August 11, 2006, Docket ID EPA-HQ-
OAR-2005-0047-0005.
---------------------------------------------------------------------------

2. Verification of Monitoring Requirements
    As noted above, the OBD system is a complex software and hardware 
system, so there are many opportunities for unintended interactions 
that can result in certain elements of the system not working as 
intended. The causes of possible problems vary from simple typing 
errors in the software code to component supplier hardware changes late 
in development or just prior to start of production. Given the 
complexity of OBD monitors and their associated algorithms, there can 
be thousands of lines of software code required to meet the diagnostic 
requirements. Implementing that code without interfering with the 
software code required for normal operation is and will be a very 
difficult task with many opportunities for human error. We expect that 
manufacturers will conduct some validation testing on end products to 
ensure that there are no problems that would be noticed by the vehicle 
operator. We believe that manufacturers should include in such 
verification testing an evaluation of the OBD system (e.g., does the 
MIL illuminate as intended in response to a malfunction?).
    Therefore, we are proposing that engine manufacturers be required 
to perform a thorough level of validation testing on at least one 
production vehicle and up to two more production engines per model 
year. The production vehicles/engines required for testing would have 
to be equipped with/be from the same engine families and ratings as 
used for the certification demonstration testing described in section 
VIII.B.3. If a manufacturer demonstrated one, two, or three engines for 
certification, then at least one production vehicle and perhaps an 
additional one to two engines would have to be tested, respectively. We 
would work with the manufacturer and CARB staff to determine the actual 
vehicles and engines to test.
    The testing itself would consist of implanting or simulating 
malfunctions to verify that virtually every single engine-related OBD 
monitor on the vehicle correctly identifies the malfunction, stores an 
appropriate DTC, and illuminates the MIL. Manufacturers would not be 
required to conduct any emissions testing. Instead, for those 
malfunctions designed against an emissions threshold, the manufacturer 
would simply implant or simulate a malfunction and verify detection, 
DTC storage, and MIL illumination. Actual ``threshold'' parts would not 
be needed for such testing. Implanted malfunctions could use severely 
deteriorated parts if desired by the manufacturer since the point of 
the testing is to verify detection, DTC storage, and MIL illumination. 
Upon submitting the data to the Administrator, the manufacturer would 
be required to also provide a description of the testing and the 
methods used to implant or simulate each malfunction. Note that testing 
of specific monitors would not be required if the manufacturer can show 
that no possible test exists that could be done on that monitor without 
causing physical damage to the production vehicle. We are proposing 
that the testing be completed and reported to us within six months 
after the manufacturer begins normal engine production. This should 
provide early feedback on the performance of every monitor on the 
vehicle prior to too many entering production. Upon good cause, we may 
extend the time period for testing.
    Note that, in their HDOBD rule,\80\ CARB allows, as an incentive to 
perform a thorough validation test, a manufacturer to request that any 
problem discovered during this self-test be treated as a 
``retroactive'' deficiency. As discussed in section VIII.B.4, we do not 
have a provision for retroactive deficiencies. Importantly, a 
retroactive deficiency granted by the Executive Officer does not 
preclude a manufacturer from complying with our defect reporting 
requirements. This issue was discussed in more detail in section 
VIII.B.4.
---------------------------------------------------------------------------

    \80\ 13 CCR 1971.1, Docket ID EPA-HQ-OAR-2005-0047-
0006.
---------------------------------------------------------------------------

3. Verification of In-Use Monitoring Performance Ratios
    We are proposing that manufacturers track the performance of 
several of the most important monitors on the engine to determine how 
often they are monitoring during in-use operation. These requirements 
are discussed in more detail in section II.E. To summarize that 
discussion, monitors would be expected to execute in the real world and 
meet a minimum acceptable performance level determined as the ratio of 
the number of good monitoring events to the number of actual trips. The 
ratio being proposed is 10 percent, meaning that monitors should 
execute during at least 10 percent of the trips taken by the engine/
vehicle. Monitors

[[Page 3282]]

that perform below the minimum ratio would be subject to remedial 
action and possibly recall. However, the minimum ratio is not effective 
until the 2013 and later model years. For the 2010 through 2012 model 
year engines certified to today's proposed OBD requirements, we are 
proposing that the data be collected even though the minimum ratio is 
not yet effective. The data gathered on these engines will help to 
determine whether the 10 percent ratio is appropriate for all 
applications and, if not, we would intend to propose a change to the 
proposed requirement to reflect that learning.
    We are proposing that manufacturers gather these data on production 
vehicles rather than engines. Since not every vehicle can be evaluated, 
we are proposing that manufacturers generate groups of engine/vehicle 
combinations to ensure adequate representation of the fleet. 
Specifically, manufacturers would be required to separate production 
vehicles into monitoring performance groups based on the following 
criteria and submit performance ratio data representative of each 
group:
     Emission control system architecture type--All engines 
that use the same or similar emissions control system architecture and 
associated monitoring system would be in the same emission architecture 
category. By architecture we mean engines with EGR+DPF+SCR, or 
EGR+DPF+NOX Adsorber, or EGR+DPF-only, etc.
     Application type--Within an emission architecture 
category, engines would be separated by vehicle application. The 
separate application categories would be based on three 
classifications: engines intended primarily for line-haul chassis 
applications, engines intended primarily for urban delivery chassis 
applications, and all other engines.
    We are proposing that these data be submitted to us within 12 
months of the production vehicles entering the market. Upon submitting 
the collected data to us, the manufacturer would also be required to 
provide a detailed description of how the data were gathered, how 
vehicles were grouped to represent sales of their engines, and the 
number of engines tested per monitoring performance group. 
Manufacturers would be required to submit performance ratio data from a 
sample of at least 15 vehicles per monitoring performance group. For 
example, a manufacturer with two emission control system architectures 
sold into each of the line-haul, urban delivery, and ``other'' 
groupings, would be required to submit data on up to 90 vehicles (i.e., 
2 x 3 x 15). We are proposing that these data be collected every year. 
Some manufacturers may find it easiest to collect data from vehicles 
that come in to its authorized repair facilities for routine 
maintenance or warranty work during the time period required, while 
others may find it more advantageous to hire a contractor to collect 
the data. Upon good cause, we may extend the time period for testing.
    As stated before, the data collected under this program are 
intended primarily to provide an early indication that the systems are 
working as intended in the field, to provide information to ``fine-
tune'' the proposed requirement to track the performance of monitors, 
and to provide data to be used to develop a more appropriate minimum 
ratio for future regulatory revisions. The data are not intended to 
substitute for testing that we would perform for enforcement reasons to 
determine if a manufacturer is complying with the minimum acceptable 
performance ratios. In fact, the data collected would not likely meet 
all the required elements for testing to make an official determination 
that the system is noncompliant. As such, we believe the testing would 
be of most value to manufacturers since monitor performance problems 
can be corrected prior to EPA conducting a full enforcement action that 
could result in a recall.

IX. What are the Issues Concerning Inspection and Maintenance Programs?

A. Current Heavy-Duty I/M Programs

    While there are currently no regulatory requirements for heavy-duty 
inspection and maintenance (I/M), and no State Implementation Plan 
(SIP) credit given for heavy-duty I/M, a recent review shows that 
programs in the United States as well as abroad are currently testing 
heavy-duty diesel and heavy-duty gasoline vehicles as part of their 
Inspection and Maintenance programs. A recent study found that the 
mandated vehicle emission I/M programs in the CAAA of 1990, originally 
required in areas where ambient levels of ozone and CO exceeded the 
national standards, are being utilized as a framework as diesel PM 
becomes increasingly recognized as an important health concern in the 
United States.\81\ Some countries outside the U.S., particularly 
developing countries, have been seeking to improve air quality by 
implementing both light-duty and heavy-duty I/M programs.
---------------------------------------------------------------------------

    \81\ Review of Light-Duty Diesel and Heavy-Duty Diesel/Gasoline 
Inspection Programs, St. Denis and Lindner, Journal of the Air and 
Waste Management Association, December 2005.
---------------------------------------------------------------------------

    In the U.S., the light-duty fleet has become cleaner. As a result, 
heavy-duty vehicles are responsible for an increasing contribution of 
the mobile source emission inventory. EPA has responded to the 
increased contribution by promulgating technology-promoting standards, 
to be phased in during the years leading up to 2010. Some non-
attainment areas are implementing HD vehicle I/M programs to improve 
their regional air quality. The current tailpipe emissions measurements 
result in a number of issues, so other technologies such as remote 
sensing are being examined. Interrogation of the OBD system on over 
14,000 pound vehicles would likely be a candidate I/M test method.
    As of 2004, according to the aforementioned study, many I/M 
programs in the U.S. have developed a wide range of emission tests for 
HD diesel vehicles and HD gasoline vehicles. 19 States currently test 
HD diesel vehicles (these are: AZ, CA, CO, CT, ID, IL, KY, ME, MD, MA, 
NV, NH, NJ, NM, NY, OH, UT, VT, WA); 25 states test HD gasoline 
vehicles (these are: AK, AZ, CA, CO, CT, ID, IL, IN, KY, MD, MA, NV, 
NJ, NM, NY, NC, OH, OR, PA, TN, TX, UT, VA, WA, WI). Canada, China, 
Singapore, Sweden, and the United Kingdom test HD diesel vehicles. 
Lastly, Germany, Singapore, and Sweden test HD gasoline vehicles.
    Whether or not voluntary or regulated inspection and maintenance 
programs become prominent, heavy-duty OBD should be designed to allow 
ease of interrogation to maximize the potential of this technology to 
help realize environmental benefit. There is evidence that localities 
are utilizing this strategy in their air quality protection programs. 
There is also a wealth of light-duty OBD experience to support making 
an I/M-type test as user-friendly as possible so technician training 
and scan tool designs do not limit the ability to assess a vehicle's 
status.

B. Challenges for Heavy-Duty I/M

    There are a number of challenges that are being discovered as 
programs implement heavy-duty I/M. Existing HD I/M programs utilize of 
a number of different emission test types, such as snap-idle testing 
(based on SAE J1667), loaded cruise testing (chassis dynamometer), ASM 
testing, Transient IMXXX, Two-Speed Idle or Curb Idle, and Lug-down 
testing. Projections of heavy-duty vehicle inventory contributions for 
VOC, NOX, PM, and toxics have substantiated the need for 
more stringent regulations. Repairs

[[Page 3283]]

based on individual emission test types, such as opacity testing, may 
target and reduce one pollutant (e.g., PM) while neglecting or 
increasing others (e.g., NOX). A sound test should 
effectively control all harmful pollutants, thus must be able to 
measure multiple pollutants--specifically PM and NOX 
emissions.
    Systems capable of measuring both pollutants at the same time have 
to date been prohibitively expensive for I/M programs, and 
traditionally require a heavy-duty dynamometer so that vehicles can be 
tested under load. Recent work has begun to investigate the use of 
remote sensing and other technologies for measuring heavy-duty gaseous 
and PM emissions. While this technology has not yet been routinely 
implemented in HD vehicle I/M programs to date, the impetus to identify 
more robust or user-friendly emission testing strategies exists. 
Portable emissions measurement systems (PEMS) are not really conducive 
to an I/M environment at this time because the units are very costly, 
require a great deal of expertise to operate, and require considerable 
time for completing a test. Such systems are best suited for intensive 
analysis of emissions performance on a limited number of vehicles 
rather than the widespread testing of nearly all vehicles as is the 
attempt in most I/M programs. All these factors heighten the potential 
that OBD systems will be utilized in I/M programs for vehicles over 
14,000 pounds.

C. Heavy-Duty OBD and I/M

    Heavy-duty OBD should be designed with the anticipation that there 
may be new use of OBD to help insure local or regional emission 
benefits. If multiple individuals are querying OBD, standardization of 
testing equipment and protocol, and information format and availability 
should be considered to maximize the effective use of this technology. 
Many of the lessons learned from the use of light-duty OBD in I/M 
programs point to a need to ensure standard protocols for testing, so 
that test equipment and data collection requirements can be 
accommodated in system designs. Along with common connectors, data 
formats, and specific parameter monitoring requirements, future 
technologies enabling standardization of data stream logic (e.g., 
built-in checks, broadcasted updates, etc.) and other currently non-
existing strategies may be attractive to minimize training requirements 
for test personnel and data management for model year-specific 
information.
    Due to the regional or national registrations of many heavy-duty 
vehicles, there is the potential that eventual I/M use of OBD to 
control heavy-duty vehicle emission exceedences could be at the fleet 
or corporate level, rather than at the state level as is the current 
light-duty convention. Stakeholders will need to inform the debate but 
today's HD I/M programs may not follow the same development pattern as 
light-duty I/M programs did a decade ago. The lessons learned from 
light-duty OBD I/M should be complemented with early data on HD I/M 
programs being piloted in the U.S. and globally.
    As one example, Ontario's Ministry of the Environment has prepared 
a report on their Heavy-Duty Drive Clean program. This study developed 
estimates of emissions benefits for inspected diesel vehicles and 
compares them to estimated baseline emissions for the case with no 
Drive Clean program, for calendar years 2000, 2001, and 2002. According 
to this study, over the three years of the program the total 
accumulated emission reductions generated by the program's operation 
were estimated to be 1092 tonnes of PM10 emissions, 654 tonnes of HC 
emissions, and 721 tonnes of NOX emissions.\82\ This 
particular study utilized opacity testing, and compared failed and 
fixed vehicles for different model year vehicles and for different 
weight classes. The malperformance model developed originally by Radian 
Corporation for ARB in 1986 was utilized since the statistical 
correlation between smoke opacity an mass emissions is weak, especially 
in newer vehicles; and the EPA MOBILE model assume zero deterioration 
of emissions for most HD diesel engines, thereby implying no benefit 
for I/M. The relationship between maintenance and emission 
deterioration is complicated by the use of high efficiency 
aftertreatment devices, which lose emission conversion efficiency with 
age, so this model's basic premise is likely appropriate only until the 
year 2008. Nevertheless, as the benefits of inspection and maintenance 
become more clearly articulated, the interest in assessing test 
methodologies that provide ease of use as well as multi-pollutant 
screening will likely increase. For these reasons consideration of 
potential I/M program use of OBD for the heavy-duty fleet is warranted, 
and should include lessons-learned from the light-duty fleet as well as 
anticipate new strategies for utilizing OBD information.
---------------------------------------------------------------------------

    \82\ ``Drive Clean Program Emission Benefit Analysis and 
Reporting--Heavy-Duty Diesel Vehicles,'' Canada Ministry of the 
Environment, October 2003.
---------------------------------------------------------------------------

    We request comment with respect to the level of interest in I/M 
programs that make use of the proposed OBD system on over 14,000 pound 
vehicles. Specifically, are states interested in I/M for over 14,000 
pound vehicles that mirrors existing programs for passenger cars and 
other light trucks? For those that might be interested, does the 
proposed OBD system meet the needs of their potential I/M program?

X. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    This action is not a ``significant regulatory action'' under the 
terms of Executive Order (EO) 12866 (58 FR 51735, October 4, 1993) and 
is, therefore, not subject to review under the EO.
    EPA prepared an analysis of the potential costs associated with 
this action. This analysis is contained in the technical support 
document.\83\ A copy of the analysis is available in the docket and was 
summarized in section VI of this preamble.
---------------------------------------------------------------------------

    \83\ Draft Technical Support Document, HDOBD NPRM, EPA420-D-06-
006, Docket ID EPA-HQ-OAR-2005-0047-0008.
---------------------------------------------------------------------------

B. Paperwork Reduction Act

    The proposed information collection requirements for this action 
have been submitted for approval to the Office of Management and Budget 
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. The 
Information Collection Request (ICR) document prepared by EPA has been 
assigned EPA ICR number 1684.09. Under Title II of the Clean Air Act 
(42 U.S.C. 7521 et seq.; CAA), EPA is charged with issuing certificates 
of conformity for those engines that comply with applicable emission 
standards. Such a certificate must be issued before engines may be 
legally introduced into commerce. EPA uses certification information to 
verify that the proper engine prototypes have been selected and that 
the necessary testing has been performed to assure that each engine 
complies with emission standards. In addition, EPA also has the 
authority under Title II of the Clean Air to ensure compliance by 
require in-use testing of vehicles and engines. EPA is proposing to 
require additional information at the time of certification to ensure 
that that on-board diagnostic (OBD) requirements are being met. EPA is 
also proposing that manufacturers conduct and report the results of in-
use testing of the OBD systems to

[[Page 3284]]

demonstrate that they are performing properly. Therefore, EPA is 
proposing 207 hours of annual burden per each of the 12 respondents to 
conduct the OBD certification, compliance, and in-use testing 
requirements proposed by this action. EPA estimates that the total of 
the of the 2484 hours of annual cost burden will be $16,018 per 
respondent for a total annual industry cost burden for the 12 
respondents of $1,236,481.
    Burden means the total time, effort, or financial resources 
expended by persons to generate, maintain, retain, or disclose or 
provide information to or for a Federal agency. technology and systems 
for the purposes of collecting, validating, and verifying. This 
includes the time needed to review instructions; develop, acquire, 
install, and utilize information, processing and maintaining 
information, and disclosing and providing information; adjust the 
existing ways to comply with any previously applicable instructions and 
requirements; train personnel to be able to respond to a collection of 
information; search data sources; complete and review the collection of 
information; and transmit or otherwise disclose the information.
    An agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations in 40 CFR are listed in 40 CFR part 9.
    To comment on the Agency's need for this information, the accuracy 
of the provided burden estimates, and any suggested methods for 
minimizing respondent burden, including the use of automated collection 
techniques, EPA has established a public docket for this rule, which 
includes this ICR, under Docket ID number EPA-HQ-OAR-2005-0047. Submit 
any comments related to the ICR for this proposed rule to EPA and OMB. 
See the ADDRESSES section at the beginning of this notice for where to 
submit comments to EPA. Send comments to OMB at the Office of 
Information and Regulatory Affairs, Office of Management and Budget, 
725 17th Street, NW., Washington, DC 20503, Attention: Desk Office for 
EPA. Since OMB is required to make a decision concerning the ICR 
between 30 and 60 days after January 24, 2007, a comment to OMB is best 
assured of having its full effect if OMB receives it by February 23, 
2007. The final rule will respond to any OMB or public comments on the 
information collection requirements contained in this proposal.

C. Regulatory Flexibility Act (RFA), as Amended by the Small Business 
Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 U.S.C. 601 et. 
seq.

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements under the Administrative 
Procedure Act or any other statute unless the agency certifies that the 
rule will not have a significant economic impact on a substantial 
number of small entities. Small entities include small businesses, 
small organizations, and small governmental jurisdictions.
    For purposes of assessing the impacts of today's proposed rule on 
small entities, small entity is defined as: (1) A motor vehicle 
manufacturer with fewer than 1,000 employees; (2) a motor vehicle 
converter with fewer than 750 employees; (3) a small governmental 
jurisdiction that is a government of a city, county, town, school 
district or special district with a population of less than 50,000; and 
(4) a small organization that is any not-for-profit enterprise which is 
independently owned and operated and is not dominant in its field. 
After considering the economic impacts of today's proposed rule on 
small entities, we have determined that this action would not have a 
significant economic impact on a substantial number of small entities. 
This proposed rule would not have any adverse economic impact on small 
entities. Today's rule places new requirements on manufacturers of 
large engines meant for highway use. These are large manufacturers. 
Today's rule also changes existing requirements on manufacturers of 
passenger car and smaller heavy-duty engines meant for highway use. 
These changes place no meaningful new requirements on those 
manufacturers.

D. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public 
Law 104-4, establishes requirements for federal agencies to assess the 
effects of their regulatory actions on state, local, and tribal 
governments, and the private sector. Under section 202 of the UMRA, EPA 
generally must prepare a written statement, including a cost-benefit 
analysis, for proposed and final rules with ``Federal mandates'' that 
may result in expenditures to state, local, and tribal governments, in 
the aggregate, or to the private sector, of $100 million or more for 
any single year. Before promulgating a rule for which a written 
statement is needed, section 205 of the UMRA generally requires EPA to 
identify and consider a reasonable number of regulatory alternatives 
and to adopt the least costly, most cost-effective, or least burdensome 
alternative that achieves the objectives of the rule. The provisions of 
section 205 do not apply when they are inconsistent with applicable 
law. Moreover, section 205 allows EPA to adopt an alternative that is 
not the least costly, most cost-effective, or least burdensome 
alternative if the Administrator publishes with the final rule an 
explanation of why such an alternative was not adopted.
    Before EPA establishes any regulatory requirement that may 
significantly or uniquely affect small governments, including tribal 
governments, it must have developed under section 203 of the UMRA a 
small government agency plan. The plan must provide for notifying 
potentially affected small governments, enabling officials of affected 
small governments to have meaningful and timely input in the 
development of EPA regulatory proposals with significant Federal 
intergovernmental mandates, and informing, educating, and advising 
small governments on compliance with the regulatory requirements.
    This rule contains no federal mandates (under the regulatory 
provisions of Title II of the UMRA) for State, local, or tribal 
governments or the private sector. The rule imposes no enforceable 
duties on any of these entities. Nothing in the rule would 
significantly or uniquely affect small governments. We have determined 
that this rule does not contain a federal mandate that may result in 
estimated expenditures of more than $100 million to the private sector 
in any single year. Therefore, the requirements of the UMRA do not 
apply to this action.

E. Executive Order 13132: Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August 
10, 1999), requires EPA to develop an accountable process to ensure 
``meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
``Policies that have federalism implications'' is defined in the 
Executive Order to include regulations that have ``substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government.''
    This proposed rule does not have federalism implications. It will 
not have substantial direct effects on the States, on the relationship 
between the national

[[Page 3285]]

government and the States, or on the distribution of power and 
responsibilities among the various levels of government, as specified 
in Executive Order 13132. This proposed rule places new requirements on 
manufacturers of large engines meant for highway use and changes 
existing requirements on manufacturers of passenger car and smaller 
heavy-duty engines meant for highway use. These changes do not affect 
States or the relationship between the national government and the 
States. Thus, Executive Order 13132 does not apply to this rule.
    In the spirit of Executive Order 13132, and consistent with EPA 
policy to promote communications between EPA and State and local 
governments, EPA specifically solicits comment on this proposed rule 
from State and local officials.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    Executive Order 13175, entitled ``Consultation and Coordination 
with Indian Tribal Governments'' (65 FR 67249, November 9, 2000), 
requires EPA to develop an accountable process to ensure ``meaningful 
and timely input by tribal officials in the development of regulatory 
policies that have tribal implications.'' This proposed rule does not 
have tribal implications, as specified in Executive Order 13175. 
Today's rule does not uniquely affect the communities of American 
Indian tribal governments since the motor vehicle requirements for 
private businesses in today's rule would have national applicability. 
Furthermore, today's rule does not impose any direct compliance costs 
on these communities and no circumstances specific to such communities 
exist that would cause an impact on these communities beyond those 
discussed in the other sections of today's document. Thus, Executive 
Order 13175 does not apply to this rule.

G. Executive Order 13045: Protection of Children From Environmental 
Health and Safety Risks

    Executive Order 13045, ``Protection of Children from Environmental 
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies 
to any rule that: (1) Is determined to be ``economically significant'' 
as defined under Executive Order 12866; and, (2) concerns an 
environmental health or safety risk that EPA has reason to believe may 
have a disproportionate effect on children. If the regulatory action 
meets both criteria, the Agency must evaluate the environmental health 
or safety effects of the planned rule on children, and explain why the 
planned regulation is preferable to other potentially effective and 
reasonably feasible alternatives considered by the Agency.
    This proposed rule is not subject to the Executive Order because it 
is not an economically significant regulatory action as defined by 
Executive Order 12866, and because the Agency does not have reason to 
believe the environmental health or safety risks addressed by this 
action present a disproportionate risk to children.

H. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution, or Use

    This rule is not subject to Executive Order 13211, ``Actions 
Concerning Regulations That Significantly Affect Energy Supply, 
Distribution, or Use'' (66 FR 28355, May 22, 2001) because it is not a 
significant regulatory action under Executive Order 12866.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Section 12(d) of Public Law 104-113, directs EPA 
to use voluntary consensus standards in its regulatory activities 
unless to do so would be inconsistent with applicable law or otherwise 
impractical. Voluntary consensus standards are technical standards 
(e.g., materials specifications, test methods, sampling procedures, and 
business practices) developed or adopted by voluntary consensus 
standards bodies. The NTTAA directs EPA to provide Congress, through 
OMB, explanations when the Agency decides not to use available and 
applicable voluntary consensus standards.
    This proposed rule references technical standards. The technical 
standards being proposed are listed in Table II.F-1 of this preamble, 
and directions for how they may be obtained are provided in section 
II.F.1. EPA welcomes comments on this aspect of the proposed rulemaking 
and, specifically, invites the public to identify other potentially-
applicable voluntary consensus standards and to explain why such 
standards should be used in this regulation.

XI. Statutory Provisions and Legal Authority

    Statutory authority for today's proposed rule is found in the Clean 
Air Act, 42 U.S.C. 7401 et seq., in particular, sections 202 and 206 of 
the Act, 42 U.S.C. 7521, 7525. This rule is being promulgated under the 
administrative and procedural provisions of Clean Air Act section 
307(d), 42 U.S.C. 7607(d).

List of Subjects in 40 CFR Part 86

    Environmental Protection, Administrative practice and procedure, 
Motor vehicle pollution.

    Dated: December 11, 2006.
Stephen L. Johnson,
Administrator.

    For the reasons set out in the preamble, part 86 of title 40 of the 
Code of Federal Regulations is proposed to be amended as follows:

PART 86--CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES 
AND ENGINES

    1. The authority citation for part 86 continues to read as follows:

    Authority: 42 U.S.C. 7401-7671q.

    2. Section 86.1 is amended as follows:
    a. In the table to paragraph (b)(2) by adding new entries to the 
end of the table.
    b. In the table to paragraph (b)(5) by adding a new entry to the 
end of the table.


Sec.  86.1  Reference materials.

* * * * *
    (b) * * *
    (2) * * *

------------------------------------------------------------------------
      Document No. and name               40 CFR part 86 reference
------------------------------------------------------------------------
 
                              * * * * * * *
SAE J1930, Electrical/Electronic   86.010-18
 Systems Diagnostic Terms,
 Definitions, Abbreviations, and
 Acronyms--Equivalent to ISO/TR
 15031-2: April 2002.
SAE J1939, MONTH 2006,             86.010-18; 86.010-38
 Recommended Practice for a
 Serial Control and
 Communications Vehicle Network.
SAE J1939-13, MONTH 2006, Off-     86.013-18
 Board Diagnostic Connector.
SAE J1962, Diagnostic Connector--  86.013-18
 Equivalent to ISO/DIS.
15031-3: April 2002..............
SAE J1978, OBD II Scan Tool--      86.010-18
 Equivalent to ISO/DIS 15031-4:
 April 2002.

[[Page 3286]]

 
SAE J1979, E/E Diagnostic Test     86.010-18; 86.010-38
 Modes--Equivalent to ISO/DIS
 15031-5: April 2002.
SAE J2012, Diagnostic Trouble      86.010-18
 Code Definitions--Equivalent to
 ISO/DIS 15031-6: April 2002.
SAE J2403, Medium/Heavy-Duty E/E   86.007-17; 86.010-18; 86.010-38;
 Systems Diagnosis Nomenclature;    86.1806-07
 August 2004.
SAE J2534, Recommended Practice    86.010-18; 86.010-38
 for Pass-Thru Vehicle
 Reprogramming: February 2002.
------------------------------------------------------------------------

* * * * *
    (5) * * *

------------------------------------------------------------------------
      Document No. and name               40 CFR part 86 reference
------------------------------------------------------------------------
 
                              * * * * * * *
ISO 15765-4:2001, Road Vehicles--  86.010-18
 Diagnostics on Controller Area
 Network (CAN)--Part 4:
 Requirements for emission-
 related systems: December 2001.
------------------------------------------------------------------------

* * * * *
    3. Section 86.007-17 is added to Subpart A to read as follows:


Sec.  86.007-17  On-board Diagnostics for engines used in applications 
less than or equal to 14,000 pounds GVWR.

    Section 86.007-17 includes text that specifies requirements that 
differ from Sec.  86.005-17. Where a paragraph in Sec.  86.005-17 is 
identical and applicable to Sec.  86.007-17, this may be indicated by 
specifying the corresponding paragraph and the statement ``[Reserved]. 
For guidance see Sec.  86.005-17.''
    (a)(1) [Reserved]. For guidance see Sec.  86.005-17.
    (a)(2) An OBD system demonstrated to fully meet the requirements in 
Sec.  86.1806-07 may be used to meet the requirements of this section, 
provided that the Administrator finds that a manufacturer's decision to 
use the flexibility in this paragraph (a)(2) is based on good 
engineering judgment.
    (b) introductory text and (b)(1)(i) [Reserved]. For guidance see 
Sec.  86.005-17.
    (b)(1)(ii) Diesel.
    (A) If equipped, catalyst deterioration or malfunction before it 
results in exhaust NOX emissions exceeding either: 1.75 
times the applicable NOX standard for engines certified to a 
NOX FEL greater than 0.50 g/bhp-hr; or, the applicable 
NOX FEL+0.5 g/bhp-hr for engines certified to a 
NOX FEL less than or equal to 0.50 g/bhp-hr. This 
requirement applies only to reduction catalysts; monitoring of 
oxidation catalysts is not required. This monitoring need not be done 
if the manufacturer can demonstrate that deterioration or malfunction 
of the system will not result in exceedance of the threshold.
    (b)(1)(ii)(B) and (b)(2) [Reserved]. For guidance see Sec.  86.005-
17.
    (b)(3)(i) Oxygen sensors and air-fuel ratio sensors downstream of 
aftertreatment devices.
    (A) Otto-cycle. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding 1.5 times the applicable 
standard or FEL for NMHC, NOX or CO.
    (B) Diesel. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding any of the following levels: 
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is 
higher; or, 1.75 times the applicable NOX standard for 
engines certified to a NOX FEL greater than 0.50 g/bhp-hr; 
or, the applicable NOX FEL+0.5 g/bhp-hr for engines 
certified to a NOX FEL less than or equal to 0.50 g/bhp-hr; 
or, 2.5 times the applicable NMHC standard.
    (ii) Oxygen sensors and air-fuel ratio sensors upstream of 
aftertreatment devices.
    (A) Otto-cycle. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding 1.5 times the applicable 
standard or FEL for NMHC, NOX or CO.
    (B) Diesel. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding any of the following levels: 
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is 
higher; or, 1.75 times the applicable NOX standard for 
engines certified to a NOX FEL greater than 0.50 g/bhp-hr; 
or, the applicable NOX FEL+0.5 g/bhp-hr for engines 
certified to a NOX FEL less than or equal to .50 g/bhp-hr; 
or, 2.5 times the applicable NMHC standard; or, 2.5 times the 
applicable CO standard.
    (iii) NOX sensors.
    (A) Otto-cycle. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding 1.5 times the applicable 
standard or FEL for NMHC, NOX or CO.
    (B) Diesel. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding any of the following levels: 
The applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is 
higher; or, 1.75 times the applicable NOX standard for 
engines certified to a NOX FEL greater than 0.50 g/bhp-hr; 
or, the applicable NOX FEL+0.5 g/bhp-hr for engines 
certified to a NOX FEL less than or equal to 0.50 g/bhp-hr.
    (b)(4) [Reserved]. For guidance see Sec.  86.005--17.
    (b)(5) Other emission control systems and components.
    (i) Otto-cycle. Any deterioration or malfunction occurring in an 
engine system or component directly intended to control emissions, 
including but not necessarily limited to, the exhaust gas recirculation 
(EGR) system, if equipped, the secondary air system, if equipped, and 
the fuel control system, singularly resulting in exhaust emissions 
exceeding 1.5 times the applicable emission standard or FEL for NMHC, 
NOX or CO. For engines equipped with a secondary air system, 
a functional check, as described in Sec.  86.005-17(b)(6), may satisfy 
the requirements of this paragraph (b)(5) provided the manufacturer can 
demonstrate that deterioration of the flow distribution system is 
unlikely. This demonstration is subject to Administrator approval and, 
if the demonstration and associated functional check are approved, the 
diagnostic system must indicate a malfunction when some degree of 
secondary airflow is not detectable in the exhaust system during the 
check. For engines equipped with positive crankcase ventilation (PCV), 
monitoring of the PCV system is not necessary provided the manufacturer 
can demonstrate to the Administrator's satisfaction that the PCV system 
is unlikely to fail.
    (ii) Diesel. Any deterioration or malfunction occurring in an 
engine system or component directly intended to control emissions, 
including but not necessarily limited to, the exhaust gas

[[Page 3287]]

recirculation (EGR) system, if equipped, and the fuel control system, 
singularly resulting in exhaust emissions exceeding any of the 
following levels: The applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr 
PM, whichever is higher; or, 1.75 times the applicable NOX 
standard for engines certified to a NOX FEL greater than 
0.50 g/bhp-hr; or, the applicable NOX FEL+0.5 g/bhp-hr for 
engines certified to a NOX FEL less than or equal to 0.50 g/
bhp-hr; or, 2.5 times the applicable NMHC standard; or, 2.5 times the 
applicable CO standard. A functional check, as described in Sec.  
86.005-17(b)(6), may satisfy the requirements of this paragraph (b)(5) 
provided the manufacturer can demonstrate that a malfunction would not 
cause emissions to exceed the applicable levels. This demonstration is 
subject to Administrator approval. For engines equipped with crankcase 
ventilation (CV), monitoring of the CV system is not necessary provided 
the manufacturer can demonstrate to the Administrator's satisfaction 
that the CV system is unlikely to fail.
    (b)(6) [Reserved]. For guidance see Sec.  86.005-17.
    (b)(7) Performance of OBD functions. Any sensor or other component 
deterioration or malfunction which renders that sensor or component 
incapable of performing its function as part of the OBD system must be 
detected and identified on engines so equipped.
    (c), (d), (e), (f), (g), and (h)(1)(i) through (h)(1)(iv) 
[Reserved]. For guidance see Sec.  86.005-17.
    (h)(1)(v) All acronyms, definitions and abbreviations shall be 
formatted according to SAE J1930 ``Electrical/Electronic Systems 
Diagnostic Terms, Definitions, Abbreviations, and Acronyms Equivalent 
to ISO/TR 15031-2: April 30, 2002'', (Revised, April 2002), or SAE 
J2403, ``Medium/Heavy-Duty E/E Systems Diagnosis Nomenclature: August 
2004.''
    (h)(1)(vi) through (h)(3) [Reserved]. For guidance see Sec.  
86.005-17.
    (i) Deficiencies and alternative fueled engines. Upon application 
by the manufacturer, the Administrator may accept an OBD system as 
compliant even though specific requirements are not fully met. Such 
compliances without meeting specific requirements, or deficiencies, 
will be granted only if compliance would be infeasible or unreasonable 
considering such factors as, but not limited to: Technical feasibility 
of the given monitor and lead time and production cycles including 
phase-in or phase-out of engines or vehicle designs and programmed 
upgrades of computers. Unmet requirements should not be carried over 
from the previous model year except where unreasonable hardware or 
software modifications would be necessary to correct the deficiency, 
and the manufacturer has demonstrated an acceptable level of effort 
toward compliance as determined by the Administrator. Furthermore, EPA 
will not accept any deficiency requests that include the complete lack 
of a major diagnostic monitor (``major'' diagnostic monitors being 
those for exhaust aftertreatment devices, oxygen sensor, air-fuel ratio 
sensor, NOX sensor, engine misfire, evaporative leaks, and 
diesel EGR, if equipped), with the possible exception of the special 
provisions for alternative fueled engines. For alternative fueled 
heavy-duty engines (e.g. natural gas, liquefied petroleum gas, 
methanol, ethanol), manufacturers may request the Administrator to 
waive specific monitoring requirements of this section for which 
monitoring may not be reliable with respect to the use of the 
alternative fuel. At a minimum, alternative fuel engines must be 
equipped with an OBD system meeting OBD requirements to the extent 
feasible as approved by the Administrator.
    (j) California OBDII compliance option. For heavy-duty engines used 
in applications weighing 14,000 pounds GVWR or less, demonstration of 
compliance with California OBD II requirements (Title 13 California 
Code of Regulations section 1968.2 (13 CCR 1968.2)), as modified and 
released on August 11, 2006, shall satisfy the requirements of this 
section, except that compliance with 13 CCR 1968.2(e)(4.2.2)(C), 
pertaining to 0.02 inch evaporative leak detection, and 13 CCR 
1968.2(d)(1.4), pertaining to tampering protection, are not required to 
satisfy the requirements of this section. Also, the deficiency 
provisions of 13 CCR 1968.2(k) do not apply. The deficiency provisions 
of paragraph (i) of this section and the evaporative leak detection 
requirement of Sec.  86.005-17(b)(4) apply to manufacturers selecting 
this paragraph for demonstrating compliance. In addition, demonstration 
of compliance with 13 CCR 1968.2(e)(15.2.1)(C), to the extent it 
applies to the verification of proper alignment between the camshaft 
and crankshaft, applies only to vehicles equipped with variable valve 
timing.
    (k) [Reserved]. For guidance see Sec.  86.005-17.
    4. Section 86.007-30 is added to Subpart A to read as follows:
    Section 86.007-30 includes text that specifies requirements that 
differ from Sec. Sec.  86.094-30, 86.095-30, 86.096-30, 86.098-30, 
86.001-30 or 86.004-30. Where a paragraph in Sec.  86.094-30, Sec.  
86.095-30, Sec.  86.096-30, Sec.  86.098-30, Sec.  86.001-30 or Sec.  
86.004-30 is identical and applicable to Sec.  86.007-30, this may be 
indicated by specifying the corresponding paragraph and the statement 
``[Reserved]. For guidance see Sec.  86.094-30.'' or ``[Reserved]. For 
guidance see Sec.  86.095-30.'' or ``[Reserved]. For guidance see Sec.  
86.096-30.'' or ``[Reserved]. For guidance see Sec.  86.098-30.'' or 
``[Reserved]. For guidance see Sec.  86.001-30.'' or ``[Reserved]. For 
guidance see 86.004-30.''


Sec.  86.007-30  Certification.

    (a)(1) and (a)(2) [Reserved]. For guidance see Sec.  86.094-30.
    (a)(3)(i) through (a)(4)(ii) [Reserved]. For guidance see Sec.  
86.004-30.
    (a)(4)(iii) introductory text through (a)(4)(iii)(C) [Reserved]. 
For guidance see Sec.  86.094-30.
    (a)(4)(iv) introductory text [Reserved]. For guidance see Sec.  
86.095-30.
    (a)(4)(iv)(A)-(a)(9) [Reserved]. For guidance see Sec.  86.094-30.
    (a)(10) and (a)(11) [Reserved]. For guidance see Sec.  86.004-30.
    (a)(12) [Reserved]. For guidance see Sec.  86.094-30.
    (a)(13) [Reserved]. For guidance see Sec.  86.095-30.
    (a)(14) [Reserved]. For guidance see Sec.  86.094-30.
    (a) (15)-(18) [Reserved]. For guidance see Sec.  86.096-30.
    (a)(19) [Reserved]. For guidance see Sec.  86.098-30.
    (a)(20) [Reserved]. For guidance see Sec.  86.001-30.
    (a)(21) [Reserved]. For guidance see Sec.  86.004-30.
    (b)(1) introductory text through (b)(1)(ii)(A) [Reserved]. For 
guidance see Sec.  86.094-30.
    (b)(1)(ii)(B) [Reserved]. For guidance see Sec.  86.004-30.
    (b)(1)(ii)(C) [Reserved]. For guidance see Sec.  86.094-30.
    (b)(1)(ii)(D) [Reserved]. For guidance see Sec.  86.004-30.
    (b)(1)(iii) and (b)(1)(iv) [Reserved]. For guidance see Sec.  
86.094-30.
    (b)(2) [Reserved]. For guidance see Sec.  86.098-30.
    (b)(3)-(b)(4)(i) [Reserved]. For guidance see Sec.  86.094-30.
    (b)(4)(ii) introductory text [Reserved]. For guidance see Sec.  
86.098-30.
    (b)(4)(ii)(A) [Reserved]. For guidance see Sec.  86.094-30.
    (b)(4)(ii)(B)-(b)(4)(iv) [Reserved]. For guidance see Sec.  86.098-
30.
    (b)(5)-(e) [Reserved]. For guidance see Sec.  86.094-30.
    (f) introductory text through (f)(1)(i) [Reserved]. For guidance 
see Sec.  86.004-30.

[[Page 3288]]

    (f)(1)(ii) Diesel.
    (A) If monitored for emissions performance--a catalyst is replaced 
with a deteriorated or defective catalyst, or an electronic simulation 
of such, resulting in exhaust emissions exceeding 1.75 times the 
applicable NOX standard for engines certified to a 
NOX FEL greater than 0.50 g/bhp-hr; or, the applicable 
NOX FEL+0.5 g/bhp-hr for engines certified to a 
NOX FEL less than or equal to 0.50 g/bhp-hr. This 
requirement applies only to reduction catalysts.
    (B) If monitored for performance--a particulate trap is replaced 
with a trap that has catastrophically failed, or an electronic 
simulation of such.
    (f)(2) [Reserved]. For guidance see Sec.  86.004-30.
    (f)(3)(i) Oxygen sensors and air-fuel ratio sensors downstream of 
aftertreatment devices.
    (A) Otto-cycle. If so equipped, any oxygen sensor or air-fuel ratio 
sensor located downstream of aftertreatment devices is replaced with a 
deteriorated or defective sensor, or an electronic simulation of such, 
resulting in exhaust emissions exceeding 1.5 times the applicable 
standard or FEL for NMHC, NOX or CO.
    (B) Diesel. If so equipped, any oxygen sensor or air-fuel ratio 
sensor located downstream of aftertreatment devices is replaced with a 
deteriorated or defective sensor, or an electronic simulation of such, 
resulting in exhaust emissions exceeding any of the following levels: 
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is 
higher; or, 1.75 times the applicable NOX standard for 
engines certified to a NOX FEL greater than 0.50 g/bhp-hr; 
or, the applicable NOX FEL+0.5 g/bhp-hr for engines 
certified to a NOX FEL less than or equal to 0.50 g/bhp-hr; 
or, 2.5 times the applicable NMHC standard.
    (ii) Oxygen sensors and air-fuel ratio sensors upstream of 
aftertreatment devices.
    (A) Otto-cycle. If so equipped, any oxygen sensor or air-fuel ratio 
sensor located upstream of aftertreatment devices is replaced with a 
deteriorated or defective sensor, or an electronic simulation of such, 
resulting in exhaust emissions exceeding 1.5 times the applicable 
standard or FEL for NMHC, NOX or CO.
    (B) Diesel. If so equipped, any oxygen sensor or air-fuel ratio 
sensor located upstream of aftertreatment devices is replaced with a 
deteriorated or defective sensor, or an electronic simulation of such, 
resulting in exhaust emissions exceeding any of the following levels: 
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is 
higher; or, 1.75 times the applicable NOX standard for 
engines certified to a NOX FEL greater than 0.50 g/bhp-hr; 
or, the applicable NOX FEL+0.5 g/bhp-hr for engines 
certified to a NOX FEL less than or equal to 0.50 g/bhp-hr; 
or, 2.5 times the applicable NMHC standard; or, 2.5 times the 
applicable CO standard.
    (iii) NOX sensors.
    (A) Otto-cycle. If so equipped, any NOX sensor is 
replaced with a deteriorated or defective sensor, or an electronic 
simulation of such, resulting in exhaust emissions exceeding 1.5 times 
the applicable standard or FEL for NMHC, NOX or CO.
    (B) Diesel. If so equipped, any NOX sensor is replaced 
with a deteriorated or defective sensor, or an electronic simulation of 
such, resulting in exhaust emissions exceeding any of the following 
levels: the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, 
whichever is higher; or, 1.75 times the applicable NOX 
standard for engines certified to a NOX FEL greater than 
0.50 g/bhp-hr; or, the applicable NOX FEL+0.5 g/bhp-hr for 
engines certified to a NOX FEL less than or equal to 0.50 g/
bhp-hr.
    (f)(4) [Reserved]. For guidance see Sec.  86.004-30.
    (f)(5)(i) Otto-cycle. A malfunction condition is induced in any 
emission-related engine system or component, including but not 
necessarily limited to, the exhaust gas recirculation (EGR) system, if 
equipped, the secondary air system, if equipped, and the fuel control 
system, singularly resulting in exhaust emissions exceeding 1.5 times 
the applicable emission standard or FEL for NMHC, NOX, or 
CO.
    (ii) Diesel. A malfunction condition is induced in any emission-
related engine system or component, including but not necessarily 
limited to, the exhaust gas recirculation (EGR) system, if equipped, 
and the fuel control system, singularly resulting in exhaust emissions 
exceeding any of the following levels: the applicable PM FEL+0.04 g/
bhp-hr or 0.05 g/bhp-hr PM, whichever is higher; or, 1.75 times the 
applicable NOX standard for engines certified to a 
NOX FEL greater than 0.50 g/bhp-hr; or, the applicable 
NOX FEL+0.5 g/bhp-hr for engines certified to a 
NOX FEL less than or equal to 0.50 g/bhp-hr; or, 2.5 times 
the applicable NMHC standard; or, 2.5 times the applicable CO standard.
    (f)(6) [Reserved]. For guidance see Sec.  86.004-30.
    5. Section 86.010-2 is added to Subpart A to read as follows:


Sec.  86.010-2  Definitions.

    The definitions of Sec.  86.004-2 continue to apply to 2004 and 
later model year vehicles. The definitions listed in this section apply 
beginning with the 2010 model year.
    Drive cycle or driving cycle means operation that consists of 
engine startup and engine shutoff during which a given onboard 
diagnostic (OBD) monitor makes a diagnostic decision. A drive cycle 
need not consist of all OBD monitors making a diagnostic decision 
during the engine startup and engine shutoff cycle. An engine restart 
following an engine shutoff that has been neither commanded by the 
vehicle operator nor by the engine control strategy but caused by an 
event such as an engine stall may be considered a new drive cycle or a 
continuation of the existing drive cycle.
    DTC means diagnostic trouble code.
    Engine start as used in Sec.  86.010-18 means the point when the 
engine reaches a speed 150 rpm below the normal, warmed-up idle speed 
(as determined in the drive position for vehicles equipped with an 
automatic transmission). For hybrid vehicles or for engines employing 
alternative engine start hardware or strategies (e.g., integrated 
starter and generators.), the manufacturer may use an alternative 
definition for engine start (e.g., key-on) provided the alternative 
definition is based on equivalence to an engine start for a 
conventional vehicle.
    Functional check, in the context of onboard diagnostics, means 
verifying that a component and/or system that receives information from 
a control computer responds properly to a command from the control 
computer.
    Ignition cycle as used in Sec.  86.010-18 means a cycle that begins 
with engine start, meets the engine start definition for at least two 
seconds plus or minus one second, and ends with engine shutoff.
    Limp-home operation as used in Sec.  86.010-18 means an operating 
mode that an engine is designed to enter upon determining that normal 
operation cannot be maintained. In general, limp-home operation implies 
that a component or system is not operating properly or is believed to 
be not operating properly.
    Malfunction means the conditions have been met that require the 
activation of an OBD malfunction indicator light and storage of a DTC.
    MIL-on DTC means the diagnostic trouble code stored when an OBD 
system has detected and confirmed that a malfunction exists (e.g., 
typically on the second drive cycle during which a given OBD monitor 
has evaluated a system or component). Industry standards may refer to 
this as a confirmed or an active DTC.

[[Page 3289]]

    Pending DTC means the diagnostic trouble code stored upon the 
detection of a potential malfunction.
    Permanent DTC means a DTC that corresponds to a MIL-on DTC and is 
stored in non-volatile random access memory (NVRAM). A permanent DTC 
can only be erased by the OBD system itself and cannot be erased 
through human interaction with the OBD system or any onboard computer.
    Previous-MIL-on DTC means a DTC that corresponds to a MIL-on DTC 
but is distinguished by representing a malfunction that the OBD system 
has determined no longer exists but for which insufficient operation 
has occurred to satisfy the DTC erasure provisions.
    Potential malfunction means that conditions have been detected that 
meet the OBD malfunction criteria but for which more drive cycles are 
allowed to provide further evaluation prior to confirming that a 
malfunction exists.
    Rationality check, in the context of onboard diagnostics, means 
verifying that a component that provides input to a control computer 
provides an accurate input to the control computer while in the range 
of normal operation and when compared to all other available 
information.
    Similar conditions, in the context of onboard diagnostics, means 
engine conditions having an engine speed within 375 rpm, load 
conditions within 20 percent, and the same warm up status (i.e., cold 
or hot). The manufacturer may use other definitions of similar 
conditions based on comparable timeliness and reliability in detecting 
similar engine operation.
    6. Section 86.010-17 is added to Subpart A to read as follows:


Sec.  86.010-17  On-board Diagnostics for engines used in applications 
less than or equal to 14,000 pounds GVWR.

    Section 86.010-17 includes text that specifies requirements that 
differ from Sec.  86.005-17 and Sec.  86.007-17. Where a paragraph in 
Sec.  86.005-17 or Sec.  86.007-17 is identical and applicable to Sec.  
86.010-17, this may be indicated by specifying the corresponding 
paragraph and the statement ``[Reserved]. For guidance see Sec.  
86.005-17.'' or ``[Reserved]. For guidance see Sec.  86.007-17.''
    (a) General.
    (1) All heavy-duty engines intended for use in a heavy-duty vehicle 
weighing 14,000 pounds GVWR or less must be equipped with an on-board 
diagnostic (OBD) system capable of monitoring all emission-related 
engine systems or components during the applicable useful life. All 
monitored systems and components must be evaluated periodically, but no 
less frequently than once per applicable certification test cycle as 
defined in Appendix I, paragraph (f), of this part, or similar trip as 
approved by the Administrator.
    (2) An OBD system demonstrated to fully meet the requirements in 
Sec.  86.1806-10 may be used to meet the requirements of this section, 
provided that the Administrator finds that a manufacturer's decision to 
use the flexibility in this paragraph (a)(2) is based on good 
engineering judgment.
    (b) Introductory text and (b)(1)(i) [Reserved]. For guidance see 
Sec.  86.005-17.
    (b)(1)(ii) Diesel.
    (A) If equipped, reduction catalyst deterioration or malfunction 
before it results in exhaust NOX emissions exceeding the 
applicable NOX FEL+0.3 g/bhp-hr. If equipped, oxidation 
catalyst deterioration or malfunction before it results in exhaust NMHC 
emissions exceeding 2.5 times the applicable NMHC standard. These 
catalyst monitoring requirements need not be done if the manufacturer 
can demonstrate that deterioration or malfunction of the system will 
not result in exceedance of the threshold.
    (B) If equipped, diesel particulate trap deterioration or 
malfunction before it results in exhaust emissions exceeding any of the 
following levels: The applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr 
PM, whichever is higher; or, exhaust NMHC emissions exceeding 2.5 times 
the applicable NMHC standard. Catastrophic failure of the particulate 
trap must also be detected. In addition, the absence of the particulate 
trap or the trapping substrate must be detected.
    (b)(2) [Reserved]. For guidance see Sec.  86.005-17.
    (b)(3)(i) Oxygen sensors and air-fuel ratio sensors downstream of 
aftertreatment devices.
    (A) Otto-cycle. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding 1.5 times the applicable 
standard or FEL for NMHC, NOX or CO.
    (B) Diesel. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding any of the following levels: 
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is 
higher; or, the applicable NOX FEL+0.3 g/bhp-hr; or, 2.5 
times the applicable NMHC standard.
    (ii) Oxygen sensors and air-fuel ratio sensors upstream of 
aftertreatment devices.
    (A) Otto-cycle. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding 1.5 times the applicable 
standard or FEL for NMHC, NOX or CO.
    (B) Diesel. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding any of the following levels: 
the applicable PM FEL+0.02 g/bhp-hr or 0.03 g/bhp-hr PM, whichever is 
higher; or, the applicable NOX FEL+0.3 g/bhp-hr; or, 2.5 
times the applicable NMHC standard; or, 2.5 times the applicable CO 
standard.
    (iii) NOX sensors.
    (A) Otto-cycle. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding 1.5 times the applicable 
standard or FEL for NMHC, NOX or CO.
    (B) Diesel. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding any of the following levels: 
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is 
higher; or, the applicable NOX FEL+0.3 g/bhp-hr.
    (b)(4) [Reserved]. For guidance see Sec.  86.005-17.
    (b)(5) Other emission control systems and components.
    (i) Otto-cycle. Any deterioration or malfunction occurring in an 
engine system or component directly intended to control emissions, 
including but not necessarily limited to, the exhaust gas recirculation 
(EGR) system, if equipped, the secondary air system, if equipped, and 
the fuel control system, singularly resulting in exhaust emissions 
exceeding 1.5 times the applicable emission standard or FEL for NMHC, 
NOX or CO. For engines equipped with a secondary air system, 
a functional check, as described in Sec.  86.005-17(b)(6), may satisfy 
the requirements of this paragraph (b)(5) provided the manufacturer can 
demonstrate that deterioration of the flow distribution system is 
unlikely. This demonstration is subject to Administrator approval and, 
if the demonstration and associated functional check are approved, the 
diagnostic system must indicate a malfunction when some degree of 
secondary airflow is not detectable in the exhaust system during the 
check. For engines equipped with positive crankcase ventilation (PCV), 
monitoring of the PCV system is not necessary provided the manufacturer 
can demonstrate to the Administrator's satisfaction that the PCV system 
is unlikely to fail.
    (ii) Diesel. Any deterioration or malfunction occurring in an 
engine system or component directly intended to control emissions, 
including but not necessarily limited to, the exhaust gas recirculation 
(EGR) system, if equipped, and the fuel control system, singularly 
resulting in exhaust emissions

[[Page 3290]]

exceeding any of the following levels: the applicable PM FEL+0.02 g/
bhp-hr or 0.03 g/bhp-hr PM, whichever is higher; or, the applicable 
NOX FEL+0.3 g/bhp-hr; or, 2.5x the applicable NMHC standard; 
or, 2.5x the applicable CO standard. A functional check, as described 
in Sec.  86.005-17(b)(6), may satisfy the requirements of this 
paragraph (b)(5) provided the manufacturer can demonstrate that a 
malfunction would not cause emissions to exceed the applicable levels. 
This demonstration is subject to Administrator approval. For engines 
equipped with crankcase ventilation (CV), monitoring of the CV system 
is not necessary provided the manufacturer can demonstrate to the 
Administrator's satisfaction that the CV system is unlikely to fail.
    (b)(6) [Reserved]. For guidance see Sec.  86.005-17.
    (b)(7) [Reserved]. For guidance see Sec.  86.007-17.
    (c) [Reserved]. For guidance see Sec.  86.005-17.
    (d) MIL illumination.
    (1) The MIL must illuminate and remain illuminated when any of the 
conditions specified in paragraph (b) of this section are detected and 
verified, or whenever the engine control enters a default or secondary 
mode of operation considered abnormal for the given engine operating 
conditions. The MIL must blink once per second under any period of 
operation during which engine misfire is occurring and catalyst damage 
is imminent. If such misfire is detected again during the following 
driving cycle (i.e., operation consisting of, at a minimum, engine 
start-up and engine shut-off) or the next driving cycle in which 
similar conditions are encountered, the MIL must maintain a steady 
illumination when the misfire is not occurring and then remain 
illuminated until the MIL extinguishing criteria of this section are 
satisfied. The MIL must also illuminate when the vehicle's ignition is 
in the ``key-on'' position before engine starting or cranking and 
extinguish after engine starting if no malfunction has previously been 
detected. If a fuel system or engine misfire malfunction has previously 
been detected, the MIL may be extinguished if the malfunction does not 
reoccur during three subsequent sequential trips during which similar 
conditions are encountered and no new malfunctions have been detected. 
Similar conditions are defined as engine speed within 375 rpm, engine 
load within 20 percent, and engine warm-up status equivalent to that 
under which the malfunction was first detected. If any malfunction 
other than a fuel system or engine misfire malfunction has been 
detected, the MIL may be extinguished if the malfunction does not 
reoccur during three subsequent sequential trips during which the 
monitoring system responsible for illuminating the MIL functions 
without detecting the malfunction, and no new malfunctions have been 
detected. Upon Administrator approval, statistical MIL illumination 
protocols may be employed, provided they result in comparable 
timeliness in detecting a malfunction and evaluating system 
performance, i.e., three to six driving cycles would be considered 
acceptable.
    (2) Drive cycle or driving cycle, in the context of this section 
Sec.  86.010-17, the definition for drive cycle or driving cycle given 
in Sec.  86.010-2 is enhanced. A drive cycle means an OBD trip that 
consists of engine startup and engine shutoff and includes the period 
of engine off time up to the next engine startup. For vehicles that 
employ engine shutoff strategies (e.g., engine shutoff at idle), the 
manufacturer may use an alternative definition for drive cycle (e.g., 
key-on followed by key-off). Any alternative definition must be based 
on equivalence to engine startup and engine shutoff signaling the 
beginning and ending of a single driving event for a conventional 
vehicle. For applications that span 14,000 pounds GVWR, the 
manufacturer may use the drive cycle definition of Sec.  86.010-18 in 
lieu of the definition in this paragraph.
    (e), (f), (g), and (h)(1)(i) through (h)(1)(iv) [Reserved]. For 
guidance see Sec.  86.005-17.
    (h)(1)(v) [Reserved]. For guidance see Sec.  86.007-17.
    (h)(1)(vi) through (h)(3) [Reserved]. For guidance see Sec.  
86.005-17.
    (i) and (j) [Reserved]. For guidance see Sec.  86.007-17.
    (k) [Reserved.]
    7. Section 86.010-18 is added to Subpart A to read as follows:


Sec.  86.010-18  On-board Diagnostics for engines used in applications 
greater than 14,000 pounds GVWR.

    (a) General. According to the implementation schedule shown in 
paragraph (o) of this section, heavy-duty engines intended for use in a 
heavy-duty vehicle weighing more than 14,000 pounds GVWR must be 
equipped with an on-board diagnostic (OBD) system capable of monitoring 
all emission-related engine systems or components during the life of 
the engine. The OBD system is required to detect all malfunctions 
specified in paragraphs (g), (h), and (i) of this section although the 
OBD system is not required to use a unique monitor to detect each of 
those malfunctions.
    (1) When the OBD system detects a malfunction, it must store a 
pending, a MIL-on, or a previous-MIL-on diagnostic trouble code (DTC) 
in the onboard computer's memory. A malfunction indicator light (MIL) 
must also be activated as specified in paragraph (b) of this section.
    (2) The OBD system must be equipped with a data link connector to 
provide access to the stored DTCs as specified in paragraph (k)(2) of 
this section.
    (3) The OBD system cannot be programmed or otherwise designed to 
deactivate based on age and/or mileage. This requirement does not alter 
existing law and enforcement practice regarding a manufacturer's 
liability for an engine beyond its regulatory useful life, except where 
an engine has been programmed or otherwise designed so that an OBD 
system deactivates based on age and/or mileage of the engine.
    (4) Drive cycle or driving cycle, in the context of this section, 
the definition for drive cycle or driving cycle given in Sec.  86.010-2 
is enhanced. A drive cycle means an OBD trip that meets any of the 
conditions of paragraphs (a)(4)(i) through (a)(4)(iv) of this section. 
Further, for OBD monitors that run during engine-off conditions, the 
period of engine-off time following engine shutoff and up to the next 
engine start may be considered part of the drive cycle for the 
conditions of paragraphs (a)(4)(i) and (a)(4)(iv) of this section. For 
engines/vehicles that employ engine shutoff OBD monitoring strategies 
that do not require the vehicle operator to restart the engine to 
continue vehicle operation (e.g., a hybrid bus with engine shutoff at 
idle), the manufacturer may use an alternative definition for drive 
cycle (e.g., key-on followed by key-off). Any alternative definition 
must be based on equivalence to engine startup and engine shutoff 
signaling the beginning and ending of a single driving event for a 
conventional vehicle. For engines that are not likely to be routinely 
operated for long continuous periods of time, a manufacturer may also 
request approval to use an alternative definition for drive cycle 
(e.g., solely based on engine start and engine shutoff without regard 
to four hours of continuous engine-on time). Administrator approval of 
the alternative definition will be based on manufacturer-submitted data 
and/or information demonstrating the typical usage, operating habits, 
and/or driving patterns of these vehicles.
    (i) Begins with engine start and ends with engine shutoff;

[[Page 3291]]

    (ii) Begins with engine start and ends after four hours of 
continuous engine-on operation;
    (iii) Begins at the end of the previous four hours of continuous 
engine-on operation and ends after four hours of continuous engine-on 
operation; or
    (iv) Begins at the end of the previous four hours of continuous 
engine-on operation and ends with engine shutoff.
    (b) Malfunction indicator light (MIL) and Diagnostic Trouble Codes 
(DTC). The OBD system must incorporate a malfunction indicator light 
(MIL) or equivalent and must store specific types of diagnostic trouble 
codes (DTC).
    (1) MIL specifications.
    (i) [Reserved.]
    (ii) The OBD system must activate the MIL when the ignition is in 
the key-on/engine-off position before engine cranking to indicate that 
the MIL is functional. The MIL shall be activated continuously during 
this functional check for a minimum of 5 seconds. During this MIL key-
on functional check, the data stream value (see paragraph (k)(4)(ii) of 
this section) for MIL status must indicate ``commanded off'' unless the 
OBD system has detected a malfunction and has stored a MIL-on DTC. This 
MIL key-on functional check is not required during vehicle operation in 
the key-on/engine-off position subsequent to the initial engine 
cranking of an ignition cycle (e.g., due to an engine stall or other 
non-commanded engine shutoff).
    (iii) As an option, the MIL may be used to indicate readiness 
status (see paragraph (k)(4)(i) of this section) in a standardized 
format in the key-on/engine-off position.
    (iv) A manufacturer may also use the MIL to indicate which, if any, 
DTCs are currently stored (e.g., to ``blink'' the stored DTCs). Such 
use must not activate unintentionally during routine driver operation.
    (v) [Reserved.]
    (2) MIL activation and DTC storage protocol.
    (i) Within 10 seconds of detecting a potential malfunction, the OBD 
system must store a pending DTC that identifies the potential 
malfunction.
    (ii) If the potential malfunction is again detected before the end 
of the next drive cycle during which monitoring occurs (i.e., the 
potential malfunction has been confirmed as a malfunction), then within 
10 seconds of such detection the OBD system must activate the MIL 
continuously and store a MIL-on DTC. If the potential malfunction is 
not detected before the end of the next drive cycle during which 
monitoring occurs (i.e., there is no indication of the malfunction at 
any time during the drive cycle), the corresponding pending DTC should 
be erased at the end of the drive cycle. Similarly, if a malfunction is 
detected for the first time and confirmed on a given drive cycle 
without need for further evaluation, then within 10 seconds of such 
detection the OBD system must activate the MIL continuously and store a 
MIL-on DTC.
    (iii) A manufacturer may request Administrator approval to employ 
alternative statistical MIL activation and DTC storage protocols to 
those specified in paragraphs (b)(2)(i) and (b)(2)(ii) of this section. 
Approval will depend upon the manufacturer providing data and/or 
engineering evaluations that demonstrate that the alternative protocols 
can evaluate system performance and detect malfunctions in a manner 
that is equally effective and timely. Strategies requiring on average 
more than six drive cycles for MIL activation will not be accepted.
    (iv) The OBD system must store a ``freeze frame'' of the operating 
conditions (as defined in paragraph (k)(4)(iii) of this section) 
present upon detecting a malfunction or a potential malfunction. In the 
event that a pending DTC has matured to a MIL-on DTC, the manufacturer 
shall either retain the currently stored freeze frame conditions or 
replace the stored freeze frame with freeze frame conditions regarding 
the MIL-on DTC. Any freeze frame stored in conjunction with any pending 
DTC or MIL-on DTC should be erased upon erasure of the corresponding 
DTC.
    (v) If the engine enters a limp-home mode of operation that can 
affect emissions or the performance of the OBD system, or in the event 
of a malfunction of an onboard computer(s) itself that can affect the 
performance of the OBD system, the OBD system must activate the MIL and 
store a MIL-on DTC within 10 seconds to inform the vehicle operator. If 
the limp-home mode of operation is recoverable (i.e., operation 
automatically returns to normal at the beginning of the following 
ignition cycle), the OBD system may wait to activate the MIL and store 
the MIL-on DTC if the limp-home mode of operation is again entered 
before the end of the next ignition cycle rather than activating the 
MIL within 10 seconds on the first drive cycle during which the limp-
home mode of operation is entered.
    (vi) Before the end of an ignition cycle, the OBD system must store 
a permanent DTC(s) that corresponds to any stored MIL-on DTC(s).
    (3) MIL deactivation and DTC erasure protocol.
    (i) Deactivating the MIL. Except as otherwise provided for in 
paragraph (g)(6)(iv)(B) of this section for empty reductant tanks, and 
paragraphs (h)(1)(iv)(F), (h)(2)(viii), and (h)(7)(iv)(B) of this 
section for gasoline fuel system, misfire, and evaporative system 
malfunctions, once the MIL has been activated, it may be deactivated 
after three subsequent sequential drive cycles during which the 
monitoring system responsible for activating the MIL functions and the 
previously detected malfunction is no longer present and provided no 
other malfunction has been detected that would independently activate 
the MIL according to the requirements outlined in paragraph (b)(2) of 
this section.
    (ii) Erasing a MIL-on DTC. The OBD system may erase a MIL-on DTC if 
the identified malfunction has not again been detected in at least 40 
engine warm up cycles and the MIL is presently not activated for that 
malfunction. The OBD system may also erase a MIL-on DTC upon 
deactivating the MIL according to paragraph (b)(3)(i) of this section 
provided a previous-MIL-on DTC is stored upon erasure of the MIL-on 
DTC. The OBD system may erase a previous-MIL-on DTC if the identified 
malfunction has not again been detected in at least 40 engine warm up 
cycles and the MIL is presently not activated for that malfunction.
    (iii) Erasing a permanent DTC. The OBD system can erase a permanent 
DTC only if either of the following conditions occur:
    (A) The OBD system itself determines that the malfunction that 
caused the corresponding MIL-on DTC to be stored is no longer present 
and is not commanding activation of the MIL, concurrent with the 
requirements of paragraph (b)(3)(i) of this section.
    (B) Subsequent to erasing the DTC information from the on-board 
computer (i.e., through the use of a scan tool or a battery 
disconnect), the OBD monitor for the malfunction that caused the 
permanent DTC to be stored has executed the minimum number of 
monitoring events necessary for MIL activation and has determined that 
the malfunction is no longer present.
    (4) Exceptions to MIL and DTC requirements.
    (i) If a limp-home mode of operation causes an overt indication 
(e.g., activation of a red engine shut-down warning light) such that 
the driver is certain to respond and have the problem corrected, a 
manufacturer may choose not to activate the MIL as required by 
paragraph (b)(2)(v) of this section. Additionally, if an auxiliary 
emission control device has been properly

[[Page 3292]]

activated as approved by the Administrator, a manufacturer may choose 
not to activate the MIL.
    (ii) For gasoline engines, a manufacturer may choose to meet the 
MIL and DTC requirements in Sec.  86.010-17 in lieu of meeting the 
requirements of paragraph (b) of Sec.  86.010-18.
    (a) Monitoring conditions. The OBD system must monitor and detect 
the malfunctions specified in paragraphs (g), (h), and (i) of this 
section under the following general monitoring conditions. The more 
specific monitoring conditions of paragraph (d) of this section are 
sometimes required according to the provisions of paragraphs (g), (h), 
and (i) of this section.
    (1) As specifically provided for in paragraphs (g), (h), and (i) of 
this section, the monitoring conditions for detecting malfunctions must 
be technically necessary to ensure robust detection of malfunctions 
(e.g., avoid false passes and false indications of malfunctions); 
designed to ensure monitoring will occur under conditions that may 
reasonably be expected to be encountered in normal vehicle operation 
and normal vehicle use; and, designed to ensure monitoring will occur 
during the FTP transient test cycle contained in Appendix I paragraph 
(f), of this part, or similar drive cycle as approved by the 
Administrator.
    (2) Monitoring must occur at least once per drive cycle in which 
the monitoring conditions are met.
    (3) Manufacturers may request approval to define monitoring 
conditions that are not encountered during the FTP cycle as required in 
paragraph (c)(1) of this section. In evaluating the manufacturer's 
request, the Administrator will consider the degree to which the 
requirement to run during the FTP transient cycle restricts monitoring 
during in-use operation, the technical necessity for defining 
monitoring conditions that are not encountered during the FTP cycle, 
data and/or an engineering evaluation submitted by the manufacturer 
that demonstrate that the component/system does not normally function 
during the FTP, whether monitoring is otherwise not feasible during the 
FTP cycle, and/or the ability of the manufacturer to demonstrate that 
the monitoring conditions satisfy the minimum acceptable in-use monitor 
performance ratio requirement as defined in paragraph (d) of this 
section.
    (d) In-use performance tracking. As specifically required in 
paragraphs (g), (h), and (i) of this section, the OBD system must 
monitor and detect the malfunctions specified in paragraphs (g), (h), 
and (i) of this section according to the criteria of this paragraph 
(d). The OBD system is not required to track and report in-use 
performance for monitors other than those specifically identified in 
paragraph (d)(1) of this section.
    (1) The manufacturer must implement software algorithms in the OBD 
system to individually track and report the in-use performance of the 
following monitors, if equipped, in the standardized format specified 
in paragraph (e) of this section: NMHC converting catalyst (paragraph 
(g)(5) of this section); NOX converting catalyst (paragraph 
(g)(6) of this section); gasoline catalyst (paragraph (h)(6) of this 
section); exhaust gas sensor (paragraph (g)(9) or (h)(8) of this 
section); evaporative system (paragraph (h)(7) of this section); EGR 
system (paragraph (g)(3) or (h)(3) of this section); VVT system 
(paragraph (g)(10) or (h)(9) of this section); secondary air system 
(paragraph (h)(5) of this section); DPF system (paragraph (g)(8) of 
this section); boost pressure control system (paragraph (g)(4) of this 
section); and, NOX adsorber system (paragraph (g)(7) of this 
section).
    (i) The manufacturer shall not use the calculated ratio specified 
in paragraph (d)(2) of this section or any other indication of monitor 
frequency as a monitoring condition for a monitor (e.g., using a low 
ratio to enable more frequent monitoring through diagnostic executive 
priority or modification of other monitoring conditions, or using a 
high ratio to enable less frequent monitoring).
    (ii) [Reserved.]
    (2) In-use performance ratio definition. For monitors required to 
meet the requirements of paragraph (d) of this section, the performance 
ratio must be calculated in accordance with the specifications of this 
paragraph (d)(2).
    (i) The numerator of the performance ratio is defined as the number 
of times a vehicle has been operated such that all monitoring 
conditions have been encountered that are necessary for the specific 
monitor to detect a malfunction.
    (ii) The denominator is defined as the number of times a vehicle 
has been operated in accordance with the provisions of paragraph (d)(4) 
of this section.
    (iii) The performance ratio is defined as the numerator divided by 
the denominator.
    (3) Specifications for incrementing the numerator.
    (i) Except as provided for in paragraph (d)(3)(v) of this paragraph 
(d)(3), the numerator, when incremented, must be incremented by an 
integer of one. The numerator shall not be incremented more than once 
per drive cycle.
    (ii) The numerator for a specific monitor must be incremented 
within 10 seconds if and only if the following criteria are satisfied 
on a single drive cycle:
    (A) Every monitoring condition has been satisfied that is necessary 
for the specific monitor to detect a malfunction and store a pending 
DTC, including applicable enable criteria, presence or absence of 
related DTCs, sufficient length of monitoring time, and diagnostic 
executive priority assignments (e.g., diagnostic ``A'' must execute 
prior to diagnostic ``B''). For the purpose of incrementing the 
numerator, satisfying all the monitoring conditions necessary for a 
monitor to determine that the monitor is not malfunctioning shall not, 
by itself, be sufficient to meet this criteria.
    (B) For monitors that require multiple stages or events in a single 
drive cycle to detect a malfunction, every monitoring condition 
necessary for all events to complete must be satisfied.
    (C) For monitors that require intrusive operation of components to 
detect a malfunction, a manufacturer must request approval of the 
strategy used to determine that, had a malfunction been present, the 
monitor would have detected the malfunction. Administrator approval of 
the request will be based on the equivalence of the strategy to actual 
intrusive operation and the ability of the strategy to determine 
accurately if every monitoring condition was satisfied that was 
necessary for the intrusive event to occur.
    (D) For the secondary air system monitor, the criteria in 
paragraphs (d)(3)(ii)(A) through (d)(3)(ii)(C) of this section are 
satisfied during normal operation of the secondary air system. 
Monitoring during intrusive operation of the secondary air system later 
in the same drive cycle for the sole purpose of monitoring shall not, 
by itself, be sufficient to meet these criteria.
    (iii) For monitors that can generate results in a ``gray zone'' or 
``non-detection zone'' (i.e., monitor results that indicate neither a 
properly operating system nor a malfunctioning system) or in a ``non-
decision zone'' (e.g., monitors that increment and decrement counters 
until a pass or fail threshold is reached), the numerator, in general, 
shall not be incremented when the monitor indicates a result in the 
``non-detection zone'' or prior to the monitor reaching a complete 
decision. When necessary, the Administrator will consider data and/or 
engineering analyses submitted by the manufacturer

[[Page 3293]]

demonstrating the expected frequency of results in the ``non-detection 
zone'' and the ability of the monitor to determine accurately, had an 
actual malfunction been present, whether or not the monitor would have 
detected a malfunction instead of a result in the ``non-detection 
zone.''
    (iv) For monitors that run or complete their evaluation with the 
engine off, the numerator must be incremented either within 10 seconds 
of the monitor completing its evaluation in the engine off state, or 
during the first 10 seconds of engine start on the subsequent drive 
cycle.
    (v) Manufacturers that use alternative statistical MIL activation 
protocols as allowed in paragraph (b)(2)(iii) of this section for any 
of the monitors requiring a numerator, are required to increment the 
numerator(s) appropriately. The manufacturer may be required to provide 
supporting data and/or engineering analyses demonstrating both the 
equivalence of their incrementing approach to the incrementing 
specified in this paragraph (d)(3) for monitors using the standard MIL 
activation protocol.
    (4) Specifications for incrementing the denominator.
    (i) The denominator, when incremented, must be incremented by an 
integer of one. The denominator shall not be incremented more than once 
per drive cycle.
    (ii) The denominator for each monitor must be incremented within 10 
seconds if and only if the following criteria are satisfied on a single 
drive cycle:
    (A) Cumulative time since the start of the drive cycle is greater 
than or equal to 600 seconds while at an elevation of less than 8,000 
feet (2,400 meters) above sea level and at an ambient temperature of 
greater than or equal to 20 degrees Fahrenheit (-7 C);
    (B) Cumulative gasoline engine operation at or above 25 miles per 
hour or diesel engine operation at or above 15% calculated load, either 
of which occurs for greater than or equal to 300 seconds while at an 
elevation of less than 8,000 feet (2,400 meters) above sea level and at 
an ambient temperature of greater than or equal to 20 degrees 
Fahrenheit (-7 C); and
    (C) Continuous vehicle operation at idle (e.g., accelerator pedal 
released by driver and vehicle speed less than or equal to one mile per 
hour) for greater than or equal to 30 seconds while at an elevation of 
less than 8,000 feet (2,400 meters) above sea level and at an ambient 
temperature of greater than or equal to 20 degrees Fahrenheit (-7 C).
    (iii) In addition to the requirements of paragraph (d)(4)(ii) of 
this section, the evaporative system monitor denominator(s) may be 
incremented if and only if:
    (A) Cumulative time since the start of the drive cycle is greater 
than or equal to 600 seconds while at an ambient temperature of greater 
than or equal to 40 degrees Fahrenheit (4 C) but less than or equal to 
95 degrees Fahrenheit (35 C); and,
    (B) Engine cold start occurs with the engine coolant temperature 
greater than or equal to 40 degrees Fahrenheit (4 C) but less than or 
equal to 95 degrees Fahrenheit (35 C) and less than or equal to 12 
degrees Fahrenheit (7 C) higher than the ambient temperature.
    (iv) In addition to the requirements of paragraph (d)(4)(ii) of 
this section, the denominator(s) for the following monitors may be 
incremented if and only if the component or strategy is commanded 
``on'' for a time greater than or equal to 10 seconds. For purposes of 
determining this commanded ``on'' time, the OBD system shall not 
include time during intrusive operation of any of the components or 
strategies that occurs later in the same drive cycle for the sole 
purpose of monitoring.
    (A) Secondary air system (paragraph (h)(5) of this section).
    (B) Cold start emission reduction strategy (paragraph (h)(4) of 
this section).
    (C) Components or systems that operate only at engine start-up 
(e.g., glow plugs, intake air heaters) and are subject to monitoring 
under ``other emission control systems'' (paragraph (i)(4) of this 
section) or comprehensive component output components (paragraph 
(i)(3)(iii) of this section).
    (v) In addition to the requirements of paragraph (d)(4)(ii) of this 
section, the denominator(s) for the following monitors of output 
components (except those operated only at engine start-up and subject 
to the requirements of paragraph (d)(4)(iv) of this section, may be 
incremented if and only if the component is commanded to function 
(e.g., commanded ``on'', ``opened'', ``closed'', ``locked'') on two or 
more occasions during the drive cycle or for a time greater than or 
equal to 10 seconds, whichever occurs first:
    (A) Variable valve timing and/or control system (paragraph (g)(10) 
or (h)(9) of this section).
    (B) ``Other emission control systems'' (paragraph (i)(4) of this 
section).
    (C) Comprehensive component output component (paragraph (i)(3) of 
this section) (e.g., turbocharger waste-gates, variable length manifold 
runners).
    (vi) For monitors of the following components, the manufacturer may 
use alternative or additional criteria for incrementing the denominator 
to that set forth in paragraph (d)(4)(ii) of this section. To do so, 
the alternative criteria must be based on equivalence to the criteria 
of paragraph (d)(4)(ii) of this section in measuring the frequency of 
monitor operation relative to the amount of engine operation:
    (A) Engine cooling system input components (paragraph (i)(1) of 
this section).
    (B) ``Other emission control systems'' (paragraph (i)(4) of this 
section).
    (C) Comprehensive component input components that require extended 
monitoring evaluation (paragraph (i)(3) of this section) (e.g., stuck 
fuel level sensor rationality).
    (vii) For monitors of the following components or other emission 
controls that experience infrequent regeneration events, the 
manufacturer may use alternative or additional criteria for 
incrementing the denominator to that set forth in paragraph (d)(4)(ii) 
of this section. To do so, the alternative criteria must be based on 
equivalence to the criteria of paragraph (d)(4)(ii) of this section in 
measuring the frequency of monitor operation relative to the amount of 
engine operation:
    (A) Oxidation catalyst (paragraph (g)(5) of this section).
    (B) DPF (paragraph (g)(8) of this section).
    (viii) For hybrids that employ alternative engine start hardware or 
strategies (e.g., integrated starter and generators), or alternative 
fuel vehicles (e.g. dedicated, bi-fuel, or dual-fuel applications), the 
manufacturer may use alternative criteria for incrementing the 
denominator to that set forth in paragraph (d)(4)(ii) of this section. 
In general, the Administrator will not approve alternative criteria for 
those hybrids that employ engine shut off only at or near idle and/or 
vehicle stop conditions. To use alternative criteria, the alternative 
criteria must be based on the equivalence to the criteria of paragraph 
(d)(4)(ii) of this section in measuring the amount of vehicle operation 
relative to the measure of conventional vehicle operation.
    (5) Disablement of numerators and denominators.
    (i) Within 10 seconds of detecting a malfunction (i.e. a pending or 
a MIL-on DTC has been stored) that disables a monitor for which the 
monitoring conditions in paragraph (d) of this section must be met, the 
OBD system must stop incrementing the numerator and denominator for any 
monitor that may be disabled as a consequence of the detected 
malfunction. Within 10 seconds of the time at which the malfunction is 
no longer being detected

[[Page 3294]]

(e.g., the pending DTC is erased through OBD system self-clearing or 
through a scan tool command), incrementing of all applicable numerators 
and denominators must resume.
    (ii) Within 10 seconds of the start of a power take-off unit (e.g., 
dump bed, snow plow blade, or aerial bucket, etc.) that disables a 
monitor for which the monitoring conditions in paragraph (d) of this 
section must be met, the OBD system must stop incrementing the 
numerator and denominator for any monitor that may be disabled as a 
consequence of power take-off operation. Within 10 seconds of the time 
at which the power take-off operation ends, incrementing of all 
applicable numerators and denominators must resume.
    (iii) Within 10 seconds of detecting a malfunction (i.e., a pending 
or a MIL-on DTC has been stored) of any component used to determine if 
the criteria of paragraphs (d)(4)(ii) and (d)(4)(iii) of this section 
are satisfied, the OBD system must stop incrementing all applicable 
numerators and denominators. Within 10 seconds of the time at which the 
malfunction is no longer being detected (e.g., the pending DTC is 
erased through OBD system self-clearing or through a scan tool 
command), incrementing of all applicable numerators and denominators 
must resume.
    (e) Standardized tracking and reporting of in-use monitor 
performance.
    (1) General. For monitors required to track and report in-use 
monitor performance according to paragraph (d) of this section, the 
performance data must be tracked and reported in accordance with the 
specifications in paragraphs (d)(2), (e), and (k)(5) of this section. 
The OBD system must separately report an in-use monitor performance 
numerator and denominator for each of the following components:
    (i) For diesel engines, NMHC catalyst bank 1, NMHC catalyst bank 2, 
NOX catalyst bank 1, NOX catalyst bank 2, exhaust 
gas sensor bank 1, exhaust gas sensor bank 2, EGR/VVT system, DPF, 
boost pressure control system, and NOX adsorber. The OBD 
system must also report a general denominator and an ignition cycle 
counter in the standardized format specified in paragraphs (e)(5), 
(e)(6), and (k)(5) of this section.
    (ii) For gasoline engines, catalyst bank 1, catalyst bank 2, 
exhaust gas sensor bank 1, exhaust gas sensor bank 2, evaporative leak 
detection system, EGR/VVT system, and secondary air system. The OBD 
system must also report a general denominator and an ignition cycle 
counter in the standardized format specified in paragraphs (e)(5), 
(e)(6), and (k)(5) of this section.
    (iii) For specific components or systems that have multiple 
monitors that are required to be reported under paragraphs (g) and (h) 
of this section (e.g., exhaust gas sensor bank 1 may have multiple 
monitors for sensor response or other sensor characteristics), the OBD 
system must separately track numerators and denominators for each of 
the specific monitors and report only the corresponding numerator and 
denominator for the specific monitor that has the lowest numerical 
ratio. If two or more specific monitors have identical ratios, the 
corresponding numerator and denominator for the specific monitor that 
has the highest denominator must be reported for the specific 
component.
    (2) Numerator.
    (i) The OBD system must report a separate numerator for each of the 
applicable components listed in paragraph (e)(1) of this section.
    (ii) The numerator(s) must be reported in accordance with the 
specifications in paragraph (k)(5)(ii) of this section.
    (3) Denominator.
    (i) The OBD system must report a separate denominator for each of 
the applicable components listed in paragraph (e)(1) of this section.
    (ii) The denominator(s) must be reported in accordance with the 
specifications in paragraph (k)(5)(ii) of this section.
    (4) Monitor performance ratio. For purposes of determining which 
corresponding numerator and denominator to report as required in 
paragraph (e)(1)(iii) of this section, the ratio must be calculated in 
accordance with the specifications in paragraph (k)(5)(iii) of this 
section.
    (5) Ignition cycle counter.
    (i) The ignition cycle counter is defined as a counter that 
indicates the number of ignition cycles a vehicle has experienced 
according to the specifications of paragraph (e)(5)(ii)(B) of this 
section. The ignition cycle counter must be reported in accordance with 
the specifications in paragraph (k)(5)(ii) of this section.
    (ii) The ignition cycle counter must be incremented as follows:
    (A) The ignition cycle counter, when incremented, must be 
incremented by an integer of one. The ignition cycle counter shall not 
be incremented more than once per ignition cycle.
    (B) The ignition cycle counter must be incremented within 10 
seconds if and only if the engine exceeds an engine speed of 50 to 150 
rpm below the normal, warmed-up idle speed (as determined in the drive 
position for engines paired with an automatic transmission) for at 
least two seconds plus or minus one second.
    (iii) Within 10 seconds of detecting a malfunction (i.e., a pending 
or a MIL-on DTC has been stored) of any component used to determine if 
the criteria in paragraph (e)(5)(ii)(B) of this section are satisfied 
(i.e., engine speed or time of operation), the OBD system must stop 
incrementing the ignition cycle counter. Incrementing of the ignition 
cycle counter shall not be stopped for any other condition. Within 10 
seconds of the time at which the malfunction is no longer being 
detected (e.g., the pending DTC is erased through OBD system self-
clearing or through a scan tool command), incrementing of the ignition 
cycle counter must resume.
    (6) General denominator.
    (i) The general denominator is defined as a measure of the number 
of times an engine has been operated according to the specifications of 
paragraph (e)(6)(ii)(B) of this section. The general denominator must 
be reported in accordance with the specifications in paragraph 
(k)(5)(ii) of this section.
    (ii) The general denominator must be incremented as follows:
    (A) The general denominator, when incremented, must be incremented 
by an integer of one. The general denominator shall not be incremented 
more than once per drive cycle.
    (B) The general denominator must be incremented within 10 seconds 
if and only if the criteria identified in paragraph (d)(4)(ii) of this 
section are satisfied on a single drive cycle.
    (C) Within 10 seconds of detecting a malfunction (i.e., a pending 
or a MIL-on DTC has been stored) of any component used to determine if 
the criteria in paragraph (d)(4)(ii) of this section are satisfied 
(i.e., vehicle speed/load, ambient temperature, elevation, idle 
operation, or time of operation), the OBD system must stop incrementing 
the general denominator. Incrementing of the general denominator shall 
not be stopped for any other condition (e.g., the disablement criteria 
in paragraphs (d)(5)(i) and (d)(5)(ii) of this section shall not 
disable the general denominator). Within 10 seconds of the time at 
which the malfunction is no longer being detected (e.g., the pending 
DTC is erased through OBD system self-clearing or through a scan tool 
command), incrementing of the general denominator must resume.
    (f) Malfunction criteria determination.
    (1) In determining the malfunction criteria for the diesel engine 
monitors required under paragraphs (g) and (i) of

[[Page 3295]]

this section that are required to indicate a malfunction before 
emissions exceed an emission threshold based on any applicable 
standard, the manufacturer must:
    (i) Use the emission test cycle and standard (i.e., the transient 
FTP or the supplemental emissions test (SET)) determined by the 
manufacturer to be more stringent (i.e., to result in higher emissions 
with the same level of monitored component malfunction). The 
manufacturer must use data and/or engineering analysis to determine the 
test cycle and standard that is more stringent.
    (ii) Identify in the certification documentation required under 
paragraph (m) of this section, the test cycle and standard determined 
by the manufacturer to be the most stringent for each applicable 
monitor.
    (iii) If the Administrator reasonably believes that a manufacturer 
has determined incorrectly the test cycle and standard that is most 
stringent, the manufacturer must be able to provide emission data and/
or engineering analysis supporting their choice of test cycle and 
standard.
    (2) On engines equipped with emission controls that experience 
infrequent regeneration events, a manufacturer must adjust the emission 
test results that are used to determine the malfunction criteria for 
monitors that are required to indicate a malfunction before emissions 
exceed a certain emission threshold. For each such monitor, the 
manufacturer must adjust the emission result as done in accordance with 
the provisions of section 86.004-28(i) with the component for which the 
malfunction criteria are being established having been deteriorated to 
the malfunction threshold. The adjusted emission value must be used for 
purposes of determining whether or not the applicable emission 
threshold is exceeded.
    (i) For purposes of this paragraph (f)(2) of this section, 
regeneration means an event, by design, during which emissions levels 
change while the emission control performance is being restored.
    (ii) For purposes of this paragraph (f)(2) of this section, 
infrequent means having an expected frequency of less than once per 
transient FTP cycle.
    (3) For gasoline engines, rather than meeting the malfunction 
criteria specified under paragraphs (h) and (i) of this section, the 
manufacturer may request approval to use an OBD system certified to the 
requirements of Sec.  86.010-17. To do so, the manufacturer must 
demonstrate use of good engineering judgment in determining equivalent 
malfunction detection criteria to those required in this section.
    (g) OBD monitoring requirements for diesel-fueled/compression-
ignition engines. The following table shows the thresholds at which 
point certain components or systems, as specified in this paragraph 
(g), are considered malfunctioning.

Table 1.--OBD Emissions Thresholds for Diesel-Fueled/Compression-Ignition Engines Meant for Placement in Applications Greater Than 14,000 Pounds GVWR (g/
                                                                         bhp-hr)
--------------------------------------------------------------------------------------------------------------------------------------------------------
              Component                   Sec.   86.010-18 reference               NMHC                   CO                    NOX               PM
--------------------------------------------------------------------------------------------------------------------------------------------------------
NMHC catalyst system................  (g)(5)............................  2.5x.................  ....................  ....................  ...........
NOX aftertreatment system...........  (g)(6), (g)(7)....................  .....................  ....................  +0.3................  ...........
Diesel particulate filter (DPF)       (g)(8)............................  2.5x.................  ....................  ....................   0.05/+0.04
 system.
Air-fuel ratio sensors upstream of    (g)(9)............................  2.5x.................  2.5x................  +0.3................   0.03/+0.02
 aftertreatment devices.
Air-fuel ratio sensors downstream of  (g)(9)............................  2.5x.................  ....................  +0.3................   0.05/+0.04
 aftertreatment devices.
NOX sensors.........................  (g)(9)............................  .....................  ....................  +0.3................   0.05/+0.04
``Other monitors'' with emissions     (g)(1), (g)(3), (g)(4), (g)(10)...  2.5x.................  2.5x................  +0.3................  0.03/+0.02
 thresholds.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: FEL=Family Emissions Limit; 2.5x std means a multiple of 2.5 times the applicable emissions standard; +0.3 means the standard or FEL plus 0.3;
  0.05/+0.04 means an absolute level of 0.05 or an additive level of the standard or FEL plus 0.04, whilchever level is higher; these emissions
  thresholds apply to the monitoring requirements of paragraph (g) of this section 86.010-18.

    (1) Fuel system monitoring.
    (i) General. The OBD system must monitor the fuel delivery system 
to verify that it is functioning properly. The individual electronic 
components (e.g., actuators, valves, sensors, pumps) that are used in 
the fuel system and are not specifically addressed in this paragraph 
(g)(1) must be monitored in accordance with the requirements of 
paragraph (i)(3) of this section.
    (ii) Fuel system malfunction criteria.
    (A) Fuel system pressure control. The OBD system must monitor the 
fuel system's ability to control to the desired fuel pressure. This 
monitoring must be done continuously unless new hardware has to be 
added, in which case the monitoring must be done at least once per 
drive cycle. The OBD system must detect a malfunction of the fuel 
system's pressure control system when the pressure control system is 
unable to maintain an engine's emissions at or below the emissions 
thresholds for ``other monitors'' as shown in Table 1 of this paragraph 
(g). For engines in which no failure or deterioration of the fuel 
system pressure control could result in an engine's emissions exceeding 
the applicable emissions thresholds, the OBD system must detect a 
malfunction when the system has reached its control limits such that 
the commanded fuel system pressure cannot be delivered.
    (B) Fuel system injection quantity. The OBD system must detect a 
malfunction of the fuel injection system when the system is unable to 
deliver the commanded quantity of fuel necessary to maintain an 
engine's emissions at or below the emissions thresholds for ``other 
monitors'' as shown in Table 1 of this paragraph (g). For engines in 
which no failure or deterioration of the fuel injection quantity could 
result in an engine's emissions exceeding the applicable emissions 
thresholds, the OBD system must detect a malfunction when the system 
has reached its control limits such that the commanded fuel quantity 
cannot be delivered.
    (C) Fuel system injection timing. The OBD system must detect a 
malfunction of the fuel injection system when the system is unable to 
deliver fuel at the proper crank angle/timing (e.g., injection timing 
too advanced or too retarded) necessary to maintain an engine's 
emissions at or below the emissions thresholds for ``other monitors'' 
as shown in Table 1 of this paragraph (g). For engines in which no 
failure or deterioration of the fuel injection timing could result in 
an engine's emissions exceeding the applicable emissions thresholds, 
the OBD system must detect a malfunction when the system has reached 
its control limits such that the commanded fuel injection timing cannot 
be achieved.

[[Page 3296]]

    (D) Fuel system feedback control. See paragraph (i)(6) of this 
section.
    (iii) Fuel system monitoring conditions.
    (A) The OBD system must monitor continuously for malfunctions 
identified in paragraphs (g)(1)(ii)(A) and (g)(1)(ii)(D) of this 
section.
    (B) The manufacturer must define the monitoring conditions for 
malfunctions identified in paragraphs (g)(1)(ii)(B) and (g)(1)(ii)(C) 
in accordance with paragraphs (c) and (d) of this section.
    (iv) Fuel system MIL activation and DTC storage. The MIL must 
activate and DTCs must be stored according to the provisions of 
paragraph (b) of this section.
    (2) Engine misfire monitoring.
    (i) General. The OBD system must monitor the engine for misfire 
causing excess emissions.
    (ii) Engine misfire malfunction criteria. The OBD system must be 
capable of detecting misfire occurring in one or more cylinders. To the 
extent possible without adding hardware for this specific purpose, the 
OBD system must also identify the specific misfiring cylinder. If more 
than one cylinder is misfiring continuously, a separate DTC must be 
stored indicating that multiple cylinders are misfiring. When 
identifying multiple cylinder misfire, the OBD system is not required 
to identify individually through separate DTCs each of the continuously 
misfiring cylinders.
    (iii) Engine misfire monitoring conditions.
    (A) The OBD system must monitor for engine misfire during engine 
idle conditions at least once per drive cycle in which the monitoring 
conditions for misfire are met. The manufacturer must be able to 
demonstrate via engineering analysis and/or data that the self-defined 
monitoring conditions: Are technically necessary to ensure robust 
detection of malfunctions (e.g., avoid false passes and false detection 
of malfunctions); require no more than 1000 cumulative engine 
revolutions; and, do not require any single continuous idle operation 
of more than 15 seconds to make a determination that a malfunction is 
present (e.g., a decision can be made with data gathered during several 
idle operations of 15 seconds or less); or, satisfy the requirements of 
paragraph (c) of this section with alternative engine operating 
conditions.
    (B) Manufacturers may employ alternative monitoring conditions 
(e.g., off-idle) provided the manufacturer is able to demonstrate that 
the alternative monitoring ensure equivalent robust detection of 
malfunctions and equivalent timeliness in detection of malfunctions.
    (iv) Engine misfire MIL activation and DTC storage. The MIL must 
activate and DTCs must be stored according to the provisions of 
paragraph (b) of this section.
    (3) EGR system monitoring.
    (i) General. The OBD system must monitor the EGR system on engines 
so equipped for low flow rate, high flow rate, and slow response 
malfunctions. For engines equipped with EGR coolers (e.g., heat 
exchangers), the OBD system must monitor the cooler for insufficient 
cooling malfunctions. The individual electronic components (e.g., 
actuators, valves, sensors) that are used in the EGR system must be 
monitored in accordance with the comprehensive component requirements 
in paragraph (i)(3) of this section.
    (ii) EGR system malfunction criteria.
    (A) EGR low flow. The OBD system must detect a malfunction of the 
EGR system prior to a decrease from the manufacturer's specified EGR 
flow rate that would cause an engine's emissions to exceed the 
emissions thresholds for ``other monitors'' as shown in Table 1 of this 
paragraph (g). For engines in which no failure or deterioration of the 
EGR system that causes a decrease in flow could result in an engine's 
emissions exceeding the applicable emissions thresholds, the OBD system 
must detect a malfunction when the system has reached its control 
limits such that it cannot increase EGR flow to achieve the commanded 
flow rate.
    (B) EGR high flow. The OBD system must detect a malfunction of the 
EGR system, including a leaking EGR valve (i.e., exhaust gas flowing 
through the valve when the valve is commanded closed) prior to an 
increase from the manufacturer's specified EGR flow rate that would 
cause an engine's emissions to exceed the emissions thresholds for 
``other monitors'' as shown in Table 1 of this paragraph (g). For 
engines in which no failure or deterioration of the EGR system that 
causes an increase in flow could result in an engine's emissions 
exceeding the applicable emissions thresholds, the OBD system must 
detect a malfunction when the system has reached its control limits 
such that it cannot reduce EGR flow to achieve the commanded flow rate.
    (C) EGR slow response. The OBD system must detect a malfunction of 
the EGR system prior to any failure or deterioration in the capability 
of the EGR system to achieve the commanded flow rate within a 
manufacturer-specified time that would cause an engine's emissions to 
exceed the emissions thresholds for ``other monitors'' as shown in 
Table 1 of this paragraph (g). The OBD system must monitor both the 
capability of the EGR system to respond to a commanded increase in flow 
and the capability of the EGR system to respond to a commanded decrease 
in flow.
    (D) EGR system feedback control. See paragraph (i)(6) of this 
section.
    (E) EGR cooler performance. The OBD system must detect a 
malfunction of the EGR cooler prior to a reduction from the 
manufacturer's specified cooling performance that would cause an 
engine's emissions to exceed the emissions thresholds for ``other 
monitors'' as shown in Table 1 of this paragraph (g). For engines in 
which no failure or deterioration of the EGR cooler could result in an 
engine's emissions exceeding the applicable emissions thresholds, the 
OBD system must detect a malfunction when the system has no detectable 
amount of EGR cooling.
    (iii) EGR system monitoring conditions.
    (A) The OBD system must monitor continuously for malfunctions 
identified in paragraphs (g)(3)(ii)(A), (g)(3)(ii)(B), and 
(g)(3)(ii)(D) of this section.
    (B) The manufacturer must define the monitoring conditions for 
malfunctions identified in paragraph (g)(3)(ii)(C) in accordance with 
paragraphs (c) and (d) of this section, with the exception that 
monitoring must occur every time the monitoring conditions are met 
during the drive cycle rather than once per drive cycle as required in 
paragraph (c)(2) of this section. For purposes of tracking and 
reporting as required in paragraph (d)(1) of this section, all monitors 
used to detect malfunctions identified in paragraph (g)(3)(ii)(C) of 
this section must be tracked separately but reported as a single set of 
values as specified in paragraph (e)(1)(iii) of this section.
    (C) The manufacturer must define the monitoring conditions for 
malfunctions identified in paragraph (g)(3)(ii)(E) of this section in 
accordance with paragraphs (c) and (d) of this section. For purposes of 
tracking and reporting as required in paragraph (d)(1) of this section, 
all monitors used to detect malfunctions identified in paragraph 
(g)(3)(ii)(E) of this section must be tracked separately but reported 
as a single set of values as specified in paragraph (e)(1)(iii) of this 
section.
    (D) The manufacturer may request Administrator approval to disable 
temporarily the EGR system monitor(s) under specific conditions (e.g., 
when freezing may affect performance of the system) provided the 
manufacturer is

[[Page 3297]]

able to demonstrate via data or engineering analysis that a reliable 
monitor cannot be run when these conditions exist.
    (iv) EGR system MIL activation and DTC storage. The MIL must 
activate and DTCs must be stored according to the provisions of 
paragraph (b) of this section.
    (4) Turbo boost control system monitoring.
    (i) General. The OBD system must monitor the boost pressure control 
system (e.g., turbocharger) on engines so equipped for under and over 
boost malfunctions. For engines equipped with variable geometry 
turbochargers (VGT), the OBD system must monitor the VGT system for 
slow response malfunctions. For engines equipped with charge air cooler 
systems, the OBD system must monitor the charge air cooler system for 
cooling system performance malfunctions. The individual electronic 
components (e.g., actuators, valves, sensors) that are used in the 
boost pressure control system must be monitored in accordance with the 
comprehensive component requirements in paragraph (i)(3) of this 
section.
    (ii) Turbo boost control system malfunction criteria.
    (A) Turbo underboost. The OBD system must detect a malfunction of 
the boost pressure control system prior to a decrease from the 
manufacturer's commanded boost pressure that would cause an engine's 
emissions to exceed the emissions thresholds for ``other monitors'' as 
shown in Table 1 of this paragraph (g). For engines in which no failure 
or deterioration of the boost pressure control system that causes a 
decrease in boost could result in an engine's emissions exceeding the 
applicable emissions thresholds, the OBD system must detect a 
malfunction when the system has reached its control limits such that it 
cannot increase boost to achieve the commanded boost pressure.
    (B) Turbo overboost. The OBD system must detect a malfunction of 
the boost pressure control system prior to an increase from the 
manufacturer's commanded boost pressure that would cause an engine's 
emissions to exceed the emissions thresholds for ``other monitors'' as 
shown in Table 1 of this paragraph (g). For engines in which no failure 
or deterioration of the boost pressure control system that causes an 
increase in boost could result in an engine's emissions exceeding the 
applicable emissions thresholds, the OBD system must detect a 
malfunction when the system has reached its control limits such that it 
cannot decrease boost to achieve the commanded boost pressure.
    (C) VGT slow response. The OBD system must detect a malfunction 
prior to any failure or deterioration in the capability of the VGT 
system to achieve the commanded turbocharger geometry within a 
manufacturer-specified time that would cause an engine's emissions to 
exceed the emissions thresholds for ``other monitors'' as shown in 
Table 1 of this paragraph (g). For engines in which no failure or 
deterioration of the VGT system response could result in an engine's 
emissions exceeding the applicable emissions thresholds, the OBD system 
must detect a malfunction of the VGT system when proper functional 
response of the system to computer commands does not occur.
    (D) Turbo boost feedback control. See paragraph (i)(6) of this 
section.
    (E) Charge air undercooling. The OBD system must detect a 
malfunction of the charge air cooling system prior to a decrease from 
the manufacturer's specified cooling rate that would cause an engine's 
emissions to exceed the emissions thresholds for ``other monitors'' as 
shown in Table 1 of this paragraph (g). For engines in which no failure 
or deterioration of the charge air cooling system that causes a 
decrease in cooling performance could result in an engine's emissions 
exceeding the applicable emissions thresholds, the OBD system must 
detect a malfunction when the system has no detectable amount of charge 
air cooling.
    (iii) Turbo boost monitoring conditions.
    (A) The OBD system must monitor continuously for malfunctions 
identified in paragraphs (g)(4)(ii)(A), (g)(4)(ii)(B), and 
(g)(4)(ii)(D) of this section.
    (B) The manufacturer must define the monitoring conditions for 
malfunctions identified in paragraph (g)(4)(ii)(C) of this section in 
accordance with paragraphs (c) and (d) of this section, with the 
exception that monitoring must occur every time the monitoring 
conditions are met during the drive cycle rather than once per drive 
cycle as required in paragraph (c)(2) of this section. For purposes of 
tracking and reporting as required in paragraph (d)(1) of this section, 
all monitors used to detect malfunctions identified in paragraph 
(g)(4)(ii)(C) of this section must be tracked separately but reported 
as a single set of values as specified in paragraph (e)(1)(iii) of this 
section.
    (C) The manufacturer must define the monitoring conditions for 
malfunctions identified in paragraph (g)(4)(ii)(E) of this section in 
accordance with paragraphs (c) and (d) of this section. For purposes of 
tracking and reporting as required in paragraph (d)(1) of this section, 
all monitors used to detect malfunctions identified in paragraph 
(g)(4)(ii)(E) of this section must be tracked separately but reported 
as a single set of values as specified in paragraph (e)(1)(iii) of this 
section.
    (iv) Turbo boost system MIL activation and DTC storage. The MIL 
must activate and DTCs must be stored according to the provisions of 
paragraph (b) of this section.
    (5) NMHC converting catalyst monitoring.
    (i) General. The OBD system must monitor the NMHC converting 
catalyst(s) for proper NMHC conversion capability. For engines equipped 
with catalyzed diesel particulate filter(s) (DPF) that convert NMHC 
emissions, the catalyst function of the DPF must be monitored in 
accordance with the DPF requirements of paragraph (g)(8) of this 
section. For purposes of this paragraph (g)(5), each catalyst that 
converts NMHC must be monitored either individually or in combination 
with others.
    (ii) NMHC converting catalyst malfunction criteria.
    (A) NMHC converting catalyst conversion efficiency. The OBD system 
must detect a catalyst malfunction when the catalyst conversion 
capability decreases to the point that NMHC emissions exceed the 
emissions thresholds for the NMHC catalyst system as shown in Table 1 
of this paragraph (g). If no failure or deterioration of the catalyst 
NMHC conversion capability could result in an engine's NMHC emissions 
exceeding the applicable emissions thresholds, the OBD system must 
detect a malfunction when the catalyst has no detectable amount of NMHC 
conversion capability.
    (B) NMHC converting catalyst aftertreatment assistance functions. 
For catalysts used to generate an exotherm to assist DPF regeneration, 
the OBD system must detect a malfunction when the catalyst is unable to 
generate a sufficient exotherm to achieve DPF regeneration. For 
catalysts used to generate a feedgas constituency to assist selective 
catalytic reduction (SCR) systems (e.g., to increase NO2 
concentration upstream of an SCR system), the OBD system must detect a 
malfunction when the catalyst is unable to generate the necessary 
feedgas constituents for proper SCR system operation. For catalysts 
located downstream of a DPF and used to convert NMHC emissions during 
DPF regeneration, the OBD system must detect a malfunction when the 
catalyst has no detectable amount of NMHC conversion capability.

[[Page 3298]]

    (iii) NMHC converting catalyst monitoring conditions. The 
manufacturer must define the monitoring conditions for malfunctions 
identified in paragraphs (g)(5)(ii)(A) and (g)(5)(ii)(B) of this 
section in accordance with paragraphs (c) and (d) of this section. For 
purposes of tracking and reporting as required in paragraph (d)(1) of 
this section, all monitors used to detect malfunctions identified in 
paragraphs (g)(5)(ii)(A) and (g)(5)(ii)(B) of this section must be 
tracked separately but reported as a single set of values as specified 
in paragraph (e)(1)(iii) of this section.
    (iv) NMHC converting catalyst MIL activation and DTC storage. The 
MIL must activate and DTCs must be stored according to the provisions 
of paragraph (b) of this section. The monitoring method for the NMHC 
converting catalyst(s) must be capable of detecting all instances, 
except diagnostic self-clearing, when a catalyst DTC has been erased 
but the catalyst has not been replaced (e.g., catalyst over-temperature 
histogram approaches are not acceptable).
    (6) Selective catalytic reduction (SCR) and lean NOX catalyst 
monitoring.
    (i) General. The OBD system must monitor the SCR and/or the lean 
NOX converting catalyst(s) for proper conversion capability. 
For engines equipped with SCR systems or other catalyst systems that 
use an active/intrusive reductant injection (e.g., active lean 
NOX catalysts that use diesel fuel post-injection or in-
exhaust injection), the OBD system must monitor the active/intrusive 
reductant injection system for proper performance. The individual 
electronic components (e.g., actuators, valves, sensors, heaters, 
pumps) in the active/intrusive reductant injection system must be 
monitored in accordance with the comprehensive component requirements 
in paragraph (i)(3) of this section. For purposes of this paragraph 
(g)(6), each catalyst that converts NOX must be monitored 
either individually or in combination with others.
    (ii) SCR and lean NOX catalyst malfunction criteria.
    (A) SCR and lean NOX catalyst conversion efficiency. The OBD system 
must detect a catalyst malfunction when the catalyst conversion 
capability decreases to the point that would cause an engine's 
emissions to exceed the emissions thresholds for NOX 
aftertreatment systems as shown in Table 1 of this paragraph (g). If no 
failure or deterioration of the catalyst NOX conversion 
capability could result in an engine's emissions exceeding any of the 
applicable emissions thresholds, the OBD system must detect a 
malfunction when the catalyst has no detectable amount of 
NOX conversion capability.
    (B) SCR and lean NOX catalyst active/intrusive reductant delivery 
performance. The OBD system must detect a malfunction prior to any 
failure or deterioration of the system to properly regulate reductant 
delivery (e.g., urea injection, separate injector fuel injection, post 
injection of fuel, air assisted injection/mixing) that would cause an 
engine's emissions to exceed any of the applicable emissions thresholds 
for NOX aftertreatment systems as shown in Table 1 of this 
paragraph (g). If no failure or deterioration of the reductant delivery 
system could result in an engine's emissions exceeding any of the 
applicable thresholds, the OBD system must detect a malfunction when 
the system has reached its control limits such that it is no longer 
able to deliver the desired quantity of reductant.
    (C) SCR and lean NOX catalyst active/intrusive reductant quantity. 
If the SCR or lean NOX catalyst system uses a reductant 
other than the fuel used for the engine, or uses a reservoir/tank for 
the reductant that is separate from the fuel tank used for the engine, 
the OBD system must detect a malfunction when there is no longer 
sufficient reductant available (e.g., the reductant tank is empty).
    (D) SCR and lean NOX catalyst active/intrusive reductant quality. 
If the SCR or lean NOX catalyst system uses a reservoir/tank 
for the reductant that is separate from the fuel tank used for the 
engine, the OBD system must detect a malfunction when an improper 
reductant is used in the reductant reservoir/tank (e.g., the reductant 
tank is filled with something other than the reductant).
    (E) SCR and lean NOX catalyst active/intrusive reductant feedback 
control. See paragraph (i)(6) of this section.
    (iii) SCR and lean NOX catalyst monitoring conditions.
    (A) The manufacturers must define the monitoring conditions for 
malfunctions identified in paragraphs (g)(6)(ii)(A) and (g)(6)(ii)(D) 
of this section in accordance with paragraphs (c) and (d) of this 
section. For purposes of tracking and reporting as required in 
paragraph (d)(1) of this section, all monitors used to detect 
malfunctions identified in paragraph (g)(6)(ii)(A) of this section must 
be tracked separately but reported as a single set of values as 
specified in paragraph (e)(1)(iii) of this section.
    (B) The OBD system must monitor continuously for malfunctions 
identified in paragraphs (g)(6)(ii)(B), (g)(6)(ii)(C), and 
(g)(6)(ii)(E) of this section.
    (iv) SCR and lean NOX catalyst MIL activation and DTC 
storage.
    (A) For malfunctions identified in paragraph (g)(6)(ii)(A) of this 
section, the MIL must activate and DTCs must be stored according to the 
provisions of paragraph (b) of this section.
    (B) For malfunctions identified in paragraphs (g)(6)(ii)(B), 
(g)(6)(ii)(C), and (g)(6)(ii)(D) of this section, the manufacturer may 
delay activating the MIL if the vehicle is equipped with an alternative 
indicator for notifying the vehicle operator of the malfunction. The 
alternative indicator must be of sufficient illumination and be located 
such that it is readily visible to the vehicle operator under all 
lighting conditions. If the vehicle is not equipped with such an 
alternative indicator and the OBD MIL activates, the MIL may be 
immediately deactivated and the corresponding DTC(s) erased once the 
OBD system has verified that the reductant tank has been refilled 
properly and the MIL has not been activated for any other malfunction. 
The Administrator may approve other strategies that provide equivalent 
assurance that a vehicle operator would be promptly notified and that 
corrective action would be taken.
    (C) The monitoring method for the SCR and lean NOX 
catalyst(s) must be capable of detecting all instances, except 
diagnostic self-clearing, when a catalyst DTC(s) has been erased but 
the catalyst has not been replaced (e.g., catalyst over-temperature 
histogram approaches are not acceptable).
    (7) NOX adsorber system monitoring.
    (i) General. The OBD system must monitor the NOX 
adsorber on engines so-equipped for proper performance. For engines 
equipped with active/intrusive injection (e.g., in-exhaust fuel and/or 
air injection) to achieve desorption of the NOX adsorber, 
the OBD system must monitor the active/intrusive injection system for 
proper performance. The individual electronic components (e.g., 
injectors, valves, sensors) that are used in the active/intrusive 
injection system must be monitored in accordance with the comprehensive 
component requirements in paragraph (i)(3) of this section.
    (ii) NOX adsorber system malfunction criteria.
    (A) NOX adsorber system capability. The OBD system must 
detect a NOX adsorber malfunction when its capability (i.e., 
its combined adsorption and conversion capability) decreases to

[[Page 3299]]

the point that would cause an engine's NOX emissions to 
exceed the emissions thresholds for NOX aftertreatment 
systems as shown in Table 1 of this paragraph (g). If no failure or 
deterioration of the NOX adsorber capability could result in 
an engine's NOX emissions exceeding the applicable emissions 
thresholds, the OBD system must detect a malfunction when the system 
has no detectable amount of NOX adsorber capability.
    (B) NOX adsorber system active/intrusive reductant 
delivery performance. For NOX adsorber systems that use 
active/intrusive injection (e.g., in-cylinder post fuel injection, in-
exhaust air-assisted fuel injection) to achieve desorption of the 
NOX adsorber, the OBD system must detect a malfunction if 
any failure or deterioration of the injection system's ability to 
properly regulate injection causes the system to be unable to achieve 
desorption of the NOX adsorber.
    (C) NOX adsorber system feedback control. Malfunction 
criteria for the NOX adsorber and the NOX 
adsorber active/instrusive reductant delivery system are contained in 
paragraph (i)(6)of this section.
    (iii) NOX adsorber system monitoring conditions.
    (A) The manufacturer must define the monitoring conditions for 
malfunctions identified in paragraph (g)(7)(ii)(A) of this section in 
accordance with paragraphs (c) and (d) of this section. For purposes of 
tracking and reporting as required in paragraph (d)(1) of this section, 
all monitors used to detect malfunctions identified in paragraph 
(g)(7)(ii)(A) of this section must be tracked separately but reported 
as a single set of values as specified in paragraph (e)(1)(iii) of this 
section.
    (B) The OBD system must monitor continuously for malfunctions 
identified in paragraphs (g)(7)(ii)(B) and (g)(7)(ii)(C) of this 
section.
    (iv) NOX adsorber system MIL activation and DTC storage. 
The MIL must activate and DTCs must be stored according to the 
provisions of paragraph (b) of this section.
    (8) Diesel particulate filter (DPF) system monitoring.
    (i) General. The OBD system must monitor the DPF on engines so-
equipped for proper performance. For engines equipped with active 
regeneration systems that use an active/intrusive injection (e.g., in-
exhaust fuel injection, in-exhaust fuel/air burner), the OBD system 
must monitor the active/intrusive injection system for proper 
performance. The individual electronic components (e.g., injectors, 
valves, sensors) that are used in the active/intrusive injection system 
must be monitored in accordance with the comprehensive component 
requirements in paragraph (i)(3) of this section.
    (ii) DPF system malfunction criteria.
    (A) DPF filtering performance. The OBD system must detect a 
malfunction prior to a decrease in the PM filtering capability of the 
DPF (e.g., cracking, melting, etc.) that would cause an engine's PM 
emissions to exceed the emissions thresholds for DPF systems as shown 
in Table 1 of this paragraph (g). If no failure or deterioration of the 
PM filtering performance could result in an engine's PM emissions 
exceeding the applicable emissions thresholds, the OBD system must 
detect a malfunction when no detectable amount of PM filtering occurs.
    (B) DPF regeneration frequency. The OBD system must detect a 
malfunction when the DPF regeneration frequency increases from (i.e., 
occurs more often than) the manufacturer's specified regeneration 
frequency to a level such that it would cause an engine's NMHC 
emissions to exceed the emissions threshold for DPF systems as shown in 
Table 1 of this paragraph (g). If no such regeneration frequency exists 
that could cause NMHC emissions to exceed the applicable emission 
threshold, the OBD system must detect a malfunction when the DPF 
regeneration frequency exceeds the manufacturer's specified design 
limits for allowable regeneration frequency.
    (C) DPF incomplete regeneration. The OBD system must detect a 
regeneration malfunction when the DPF does not properly regenerate 
under manufacturer-defined conditions where regeneration is designed to 
occur.
    (D) DPF NMHC conversion. For any DPF that serves to convert NMHC 
emissions, the OBD system must detect a malfunction when the NMHC 
conversion capability decreases to the point that NMHC emissions exceed 
the emissions threshold for DPF systems as shown in Table 1 of this 
paragraph (g). If no failure or deterioration of the NMHC conversion 
capability could result in NMHC emissions exceeding the applicable 
threshold, the OBD system must detect a malfunction when the system has 
no detectable amount of NMHC conversion capability.
    (E) DPF missing substrate. The OBD system must detect a malfunction 
if either the DPF substrate is completely destroyed, removed, or 
missing, or if the DPF assembly has been replaced with a muffler or 
straight pipe.
    (F) DPF system active/intrusive injection. For DPF systems that use 
active/intrusive injection (e.g., in-cylinder post fuel injection, in-
exhaust air-assisted fuel injection) to achieve regeneration of the 
DPF, the OBD system must detect a malfunction if any failure or 
deterioration of the injection system's ability to properly regulate 
injection causes the system to be unable to achieve regeneration of the 
DPF.
    (G) DPF regeneration feedback control. See paragraph (i)(6) of this 
section.
    (iii) DPF monitoring conditions. The manufacturer must define the 
monitoring conditions for malfunctions identified in paragraph 
(g)(8)(ii) of this section in accordance with paragraphs (c) and (d) of 
this section, with the exception that monitoring must occur every time 
the monitoring conditions are met during the drive cycle rather than 
once per drive cycle as required in paragraph (c)(2) of this section. 
For purposes of tracking and reporting as required in paragraph (d)(1) 
of this section, all monitors used to detect malfunctions identified in 
paragraph (g)(8)(ii) of this section must be tracked separately but 
reported as a single set of values as specified in paragraph 
(e)(1)(iii) of this section.
    (iv) DPF system MIL activation and DTC storage. The MIL must 
activate and DTCs must be stored according to the provisions of 
paragraph (b) of this section.
    (9) Exhaust gas sensor and sensor heater monitoring.
    (i) General. The OBD system must monitor for proper output signal, 
activity, response rate, and any other parameter that can affect 
emissions, all exhaust gas sensors (e.g., oxygen, air-fuel ratio, 
NOX) used for emission control system feedback (e.g., EGR 
control/feedback, SCR control/feedback, NOX adsorber 
control/feedback) and/or as a monitoring device. For engines equipped 
with heated exhaust gas sensors, the OBD system must monitor the heater 
for proper performance.
    (ii) Malfunction criteria for air-fuel ratio sensors located 
upstream of aftertreatment devices.
    (A) Sensor performance. The OBD system must detect a malfunction 
prior to any failure or deterioration of the sensor voltage, 
resistance, impedance, current, response rate, amplitude, offset, or 
other characteristic(s) that would cause an engine's emissions to 
exceed the emissions thresholds for ``other monitors'' as shown in 
Table 1 of this paragraph (g).
    (B) Circuit integrity. The OBD system must detect malfunctions of 
the sensor related to a lack of circuit continuity or signal out-of-
range values.
    (C) Feedback function. The OBD system must detect a malfunction of 
the

[[Page 3300]]

sensor if the emission control system (e.g., EGR, SCR, or 
NOX adsorber) is unable to use that sensor as a feedback 
input (e.g., causes limp-home or open-loop operation).
    (D) Monitoring function. To the extent feasible, the OBD system 
must detect a malfunction of the sensor when the sensor output voltage, 
resistance, impedance, current, amplitude, activity, offset, or other 
characteristics are no longer sufficient for use as an OBD system 
monitoring device (e.g., for catalyst, EGR, SCR, or NOX 
adsorber monitoring).
    (iii) Malfunction criteria for air-fuel ratio sensors located 
downstream of aftertreatment devices.
    (A) Sensor performance. The OBD system must detect a malfunction 
prior to any failure or deterioration of the sensor voltage, 
resistance, impedance, current, response rate, amplitude, offset, or 
other characteristic(s) that would cause an engine's emissions to 
exceed the emissions thresholds for air-fuel ratio sensors downstream 
of aftertreatment devices as shown in Table 1 of this paragraph (g).
    (B) Circuit integrity. The OBD system must detect malfunctions of 
the sensor related to a lack of circuit continuity or signal out-of-
range values.
    (C) Feedback function. The OBD system must detect a malfunction of 
the sensor if the emission control system (e.g., EGR, SCR, or 
NOX adsorber) is unable to use that sensor as a feedback 
input (e.g., causes limp-home or open-loop operation).
    (D) Monitoring function. To the extent feasible, the OBD system 
must detect a malfunction of the sensor when the sensor output voltage, 
resistance, impedance, current, amplitude, activity, offset, or other 
characteristics are no longer sufficient for use as an OBD system 
monitoring device (e.g., for catalyst, EGR, SCR, or NOX 
adsorber monitoring).
    (iv) Malfunction criteria for NOX sensors.
    (A) Sensor performance. The OBD system must detect a malfunction 
prior to any failure or deterioration of the sensor voltage, 
resistance, impedance, current, response rate, amplitude, offset, or 
other characteristic(s) that would cause an engine's emissions to 
exceed the emissions thresholds for NOX sensors as shown in 
Table 1 of this paragraph (g).
    (B) Circuit integrity. The OBD system must detect malfunctions of 
the sensor related to a lack of circuit continuity or signal out-of-
range values.
     (C) Feedback function.The OBD system must detect a malfunction of 
the sensor if the emission control system (e.g., EGR, SCR, or 
NOX adsorber) is unable to use that sensor as a feedback 
input (e.g., causes limp-home or open-loop operation).
    (D) Monitoring function. To the extent feasible, the OBD system 
must detect a malfunction of the sensor when the sensor output voltage, 
resistance, impedance, current, amplitude, activity, offset, or other 
characteristics are no longer sufficient for use as an OBD system 
monitoring device (e.g., for catalyst, EGR, SCR, or NOX 
adsorber monitoring).
    (v) Malfunction criteria for other exhaust gas sensors. For other 
exhaust gas sensors, the manufacturer must submit a monitoring plan to 
the Administrator for approval. The plan must include data and/or 
engineering evaluations that demonstrate that the monitoring plan is as 
reliable and effective as the monitoring required in paragraphs 
(g)(9)(ii) through (g)(9)(iv) of this section.
    (vi) Malfunction criteria for exhaust gas sensor heaters.
    (A) The OBD system must detect a malfunction of the heater 
performance when the current or voltage drop in the heater circuit is 
no longer within the manufacturer's specified limits for normal 
operation (i.e., within the criteria required to be met by the 
component vendor for heater circuit performance at high mileage). The 
manufacturer may use other malfunction criteria for heater performance 
malfunctions. To do so, the manufacturer must be able to demonstrate 
via data and/or an engineering evaluation that the monitor is reliable 
and robust.
    (B) The OBD system must detect malfunctions of the heater circuit 
including open or short circuits that conflict with the commanded state 
of the heater (e.g., shorted to 12 Volts when commanded to 0 Volts 
(ground)).
    (vii) Monitoring conditions for exhaust gas sensors.
    (A) The manufacturer must define the monitoring conditions for 
malfunctions identified in paragraphs (g)(9)(ii)(A), (g)(9)(iii)(A), 
and (g)(9)(iv)(A) of this section (i.e., sensor performance) in 
accordance with paragraphs (c) and (d) of this section. For purposes of 
tracking and reporting as required in paragraph (d)(1) of this section, 
all monitors used to detect malfunctions identified in paragraphs 
(g)(9)(ii)(A), (g)(9)(iii)(A), and (g)(9)(iv)(A) of this section must 
be tracked separately but reported as a single set of values as 
specified in paragraph (e)(1)(iii) of this section.
    (B) The manufacturer must define the monitoring conditions for 
malfunctions identified in paragraphs (g)(9)(ii)(D), (g)(9)(iii)(D), 
and (g)(9)(iv)(D) of this section (i.e., monitoring function) in 
accordance with paragraphs (c) and (d) of this section with the 
exception that monitoring must occur every time the monitoring 
conditions are met during the drive cycle rather than once per drive 
cycle as required in paragraph (c)(2) of this section.
    (C) Except as provided for in paragraph (g)(9)(vii)(D) of this 
paragraph (g)(9), the OBD system must monitor continuously for 
malfunctions identified in paragraphs (g)(9)(ii)(B), (g)(9)(ii)(C), 
(g)(9)(iii)(B), (g)(9)(iii)(C), (g)(9)(iv)(B), and (g)(9)(iv)(C) (i.e., 
circuit integrity and feedback function).
    (D) A manufacturer may request approval to disable continuous 
exhaust gas sensor monitoring when an exhaust gas sensor malfunction 
cannot be distinguished from other effects (e.g., disable monitoring 
for out-of-range on the low side during fuel cut conditions). To do so, 
the manufacturer must demonstrate via data and/or engineering analyses 
that a properly functioning sensor cannot be distinguished from a 
malfunctioning sensor and that the disablement interval is limited only 
to that necessary for avoiding false malfunction detection.
    (viii) Monitoring conditions for exhaust gas sensor heaters.
    (A) The manufacturer must define monitoring conditions for 
malfunctions identified in paragraph (g)(9)(vi)(A) of this section 
(i.e., sensor heater performance) in accordance with paragraphs (c) and 
(d) of this section.
    (B) The OBD system must monitor continuously for malfunctions 
identified in paragraph (g)(9)(vi)(B) of this section (i.e., circuit 
malfunctions).
    (ix) Exhaust gas sensor and sensor heater MIL activation and DTC 
storage. The MIL must activate and DTCs must be stored according to the 
provisions of paragraph (b) of this section.
    (10) Variable Valve Timing (VVT) system monitoring.
    (i) General. The OBD system must monitor the VVT system on engines 
so equipped for target error and slow response malfunctions. The 
individual electronic components (e.g., actuators, valves, sensors) 
that are used in the VVT system must be monitored in accordance with 
the comprehensive components requirements in paragraph (i)(3) of this 
section.
    (ii) VVT system malfunction criteria.
    (A) VVT system target error. The OBD system must detect a 
malfunction prior to any failure or deterioration in the capability of 
the VVT system to achieve the commanded valve timing and/or control 
within a crank angle and/or lift tolerance that would cause an engine's

[[Page 3301]]

emissions to exceed the emission thresholds for ``other monitors'' as 
shown in Table 1 of this paragraph (g).
    (B) VVT slow response. The OBD system must detect a malfunction 
prior to any failure or deterioration in the capability of the VVT 
system to achieve the commanded valve timing and/or control within a 
manufacturer-specified time that would cause an engine's emissions to 
exceed the emission thresholds for ``other monitors'' as shown in Table 
1 of this paragraph (g).
    (C) For engines in which no failure or deterioration of the VVT 
system could result in an engine's emissions exceeding the applicable 
emissions thresholds of paragraphs (g)(10)(ii)(A) and (g)(10)(ii)(B) of 
this section, the OBD system must detect a malfunction of the VVT 
system when proper functional response of the system to computer 
commands does not occur.
    (iii) VVT system monitoring conditions. Manufacturers must define 
the monitoring conditions for VVT system malfunctions identified in 
paragraph (g)(10)(ii) of this section in accordance with paragraphs (c) 
and (d) of this section, with the exception that monitoring must occur 
every time the monitoring conditions are met during the drive cycle 
rather than once per drive cycle as required in paragraph (c)(2) of 
this section. For purposes of tracking and reporting as required in 
paragraph (d)(1) of this section, all monitors used to detect 
malfunctions identified in paragraph (g)(10)(ii) of this section must 
be tracked separately but reported as a single set of values as 
specified in paragraph (e)(1)(iii) of this section.
    (iv) VVT MIL activation and DTC storage. The MIL must activate and 
DTCs must be stored according to the provisions of paragraph (b) of 
this section.
    (h) OBD monitoring requirements for gasoline-fueled/spark-ignition 
engines. The following table shows the thresholds at which point 
certain components or systems, as specified in this paragraph (h), are 
considered malfunctioning.

      Table 2.--OBD Emissions Thresholds for Gasoline-Fueled/Spark-Ignition Engines Meant for Placement in
                             Applications Greater Than 14,000 Pounds GVWR (g/bhp-hr)
----------------------------------------------------------------------------------------------------------------
                                                                                               Sec.   86.010-18
            Component                    NOX                 NMHC                 CO              reference
----------------------------------------------------------------------------------------------------------------
Catalyst system.................  1.75x std........  1.75x std..........  .................  (h)(6).
Evaporative emissions control     .................  0.150 inch leak....  .................  (h)(7).
 system.
``Other monitors'' with           1.5x std.........  1.5x std...........  1.5x std.........  (h)(1), (h)(2),
 emissions thresholds.                                                                        (h)(3), (h)(4),
                                                                                              (h)(5), (h)(8),
                                                                                              (h)(9).
----------------------------------------------------------------------------------------------------------------
Notes: 1.75x std means a multiple of 1.75 times the applicable emissions standard; these emissions thresholds
  apply to the monitoring requirements of paragraph (h) of this section 86.010-18; The evaporative emissions
  control system threshold is not, technically, an emissions threshold but rather a leak size that must be
  detected; nonetheless, for ease we refer to this as the threshold.

    (1) Fuel system monitoring.
    (i) General. The OBD system must monitor the fuel delivery system 
to determine its ability to provide compliance with emission standards.
    (ii) Fuel system malfunction criteria.
    (A) The OBD system must detect a malfunction of the fuel delivery 
system (including feedback control based on a secondary oxygen sensor) 
when the fuel delivery system is unable to maintain an engine's 
emissions at or below the emissions thresholds for ``other monitors'' 
as shown in Table 2 of this paragraph (h).
    (B) Except as provided for in paragraph (h)(1)(ii)(C) of this 
section, if the engine is equipped with adaptive feedback control, the 
OBD system must detect a malfunction when the adaptive feedback control 
has used up all of the adjustment allowed by the manufacturer.
    (C) If the engine is equipped with feedback control that is based 
on a secondary oxygen (or equivalent) sensor, the OBD system is not 
required to detect a malfunction of the fuel system solely when the 
feedback control based on a secondary oxygen sensor has used up all of 
the adjustment allowed by the manufacturer. However, if a failure or 
deterioration results in engine emissions that exceed the emissions 
thresholds for ``other monitors'' as shown in Table 2 of this paragraph 
(h), the OBD system is required to detect a malfunction.
    (D) The OBD system must detect a malfunction whenever the fuel 
control system fails to enter closed loop operation following engine 
start within a manufacturer specified time interval. The specified time 
interval must be supported by data and/or engineering analyses 
submitted by the manufacturer.
    (E) The manufacturer may adjust the malfunction criteria and/or 
monitoring conditions to compensate for changes in altitude, for 
temporary introduction of large amounts of purge vapor, or for other 
similar identifiable operating conditions when such conditions occur.
    (iii) Fuel system monitoring conditions. The fuel system must be 
monitored continuously for the presence of a malfunction.
    (iv) Fuel system MIL activation and DTC storage.
    (A) A pending DTC must be stored immediately upon the fuel system 
exceeding the malfunction criteria established in paragraph (h)(1)(ii) 
of this section.
    (B) Except as provided for in paragraph (h)(1)(iv)(C) of this 
section, if a pending DTC is stored, the OBD system must activate the 
MIL immediately and store a MIL-on DTC if a malfunction is again 
detected during either the drive cycle immediately following storage of 
the pending DTC regardless of the conditions encountered during that 
drive cycle, or on the next drive cycle in which similar conditions are 
encountered to those that occurred when the pending DTC was stored. 
Similar conditions means engine conditions having an engine speed 
within 375 rpm, load conditions within 20 percent, and the same warm up 
status (i.e., cold or hot) as the engine conditions stored pursuant to 
paragraph (h)(1)(iv)(E) of this section. Other definitions of similar 
conditions may be used but must result in comparable timeliness and 
reliability in detecting similar engine operation.
    (C) The pending DTC may be erased at the end of the next drive 
cycle in which similar conditions have been encountered without having 
again exceeded the specified fuel system malfunction criteria. The 
pending DTC may also be erased if similar conditions are not 
encountered during the 80 drive cycles immediately following detection 
of the potential malfunction for which the pending DTC was stored.
    (D) Storage of freeze frame conditions. The OBD system must store 
and erase freeze frame conditions either in conjunction with storing 
and erasing a pending DTC or in conjunction with storing and erasing a 
MIL-on DTC. Freeze frame information associated with a fuel system 
malfunction shall be

[[Page 3302]]

stored in preference to freeze frame information required elsewhere in 
paragraphs (h) or (i) of this section.
    (E) Storage of fuel system conditions for determining similar 
conditions of operation. The OBD must store the engine speed, load, and 
warm-up status present at the time it first detects a potential 
malfunction meeting the criteria of paragraph (h)(1)(ii) of this 
section and stores a pending DTC.
    (F) Deactivating the MIL. The MIL may be extinguished after three 
sequential driving cycles in which similar conditions have been 
encountered without detecting a malfunction of the fuel system.
    (2) Engine misfire monitoring.
    (i) General.
    (A) The OBD system must monitor the engine for misfire causing 
catalyst damage and misfire causing excess emissions.
    (B) The OBD system must identify the specific cylinder that is 
misfiring. The manufacturer may store a general misfire DTC instead of 
a cylinder specific DTC under certain operating conditions. To do so, 
the manufacturer must submit data and/or engineering analyses that 
demonstrate that the misfiring cylinder cannot be identified reliably 
when the conditions occur.
    (C) If more than one cylinder is misfiring, a separate DTC must be 
stored to indicate that multiple cylinders are misfiring unless 
otherwise allowed by this paragraph (h)(2). When identifying multiple 
cylinder misfire, the OBD system is not required to also identify using 
separate DTCs each of the misfiring cylinders individually. If more 
than 90 percent of the detected misfires occur in a single cylinder, an 
appropriate DTC may be stored that indicates the specific misfiring 
cylinder rather than storing the multiple cylinder misfire DTC. If two 
or more cylinders individually have more than 10 percent of the total 
number of detected misfires, a multiple cylinder DTC must be stored.
    (ii) Engine misfire malfunction criteria.
    (A) Misfire causing catalyst damage. The manufacturer must 
determine the percentage of misfire evaluated in 200 revolution 
increments for each engine speed and load condition that would result 
in a temperature that causes catalyst damage. If this percentage of 
misfire is exceeded, it shall be considered a malfunction that must be 
detected. For every engine speed and load condition for which this 
percentage of misfire is determined to be lower than five percent, the 
manufacturer may set the malfunction criteria at five percent. The 
manufacturer may use a longer interval than 200 revolutions but only 
for determining, on a given drive cycle, the first misfire exceedance 
as provided in paragraph (h)(2)(iv)(A) of this section. To do so, the 
manufacturer must demonstrate that the interval is not so long that 
catalyst damage would occur prior to the interval being elapsed.
    (B) Misfire causing emissions to exceed the applicable thresholds. 
The manufacturer must determine the percentage of misfire evaluated in 
1000 revolution increments that would cause emissions from an emissions 
durability demonstration engine to exceed the emissions thresholds for 
``other monitors'' as shown in Table 2 of this paragraph (h) if that 
percentage of misfire were present from the beginning of the test. If 
this percentage of misfire is exceeded, regardless of the pattern of 
misfire events (e.g., random, equally spaced, continuous), it shall be 
considered a malfunction that must be detected. To establish this 
percentage of misfire, the manufacturer must use misfire events 
occurring at equally spaced, complete engine cycle intervals, across 
randomly selected cylinders throughout each 1000-revolution increment. 
If this percentage of misfire is determined to be lower than one 
percent, the manufacturer may set the malfunction criteria at one 
percent. The manufacturer may use a longer interval than 1000 
revolutions. To do so, the manufacturer must demonstrate that the 
strategy would be equally effective and timely at detecting misfire.
    (iii) Engine misfire monitoring conditions.
    (A) The OBD system must monitor continuously for misfire under the 
following conditions: from no later than the end of the second 
crankshaft revolution after engine start; during the rise time and 
settling time for engine speed to reach the desired idle engine speed 
at engine start-up (i.e., ``flare-up'' and ``flare-down''); and, under 
all positive torque engine speeds and load conditions except within the 
engine operating region bound by the positive torque line (i.e., engine 
load with the transmission in neutral), and the points represented by 
an engine speed of 3000 rpm with the engine load at the positive torque 
line and the redline engine speed with the engine's manifold vacuum at 
four inches of mercury lower than that at the positive torque line. For 
this purpose, redline engine speed is defined as either the recommended 
maximum engine speed as displayed on the instrument panel tachometer, 
or the engine speed at which fuel shutoff occurs.
    (B) If an OBD monitor cannot detect all misfire patterns under all 
required engine speed and load conditions as required by paragraph 
(h)(2)(iii)(A) of this section, the OBD system may still be acceptable. 
The Administrator will evaluate the following factors in making a 
determination: the magnitude of the region(s) in which misfire 
detection is limited; the degree to which misfire detection is limited 
in the region(s) (i.e., the probability of detection of misfire 
events); the frequency with which said region(s) are expected to be 
encountered in-use; the type of misfire patterns for which misfire 
detection is troublesome; and demonstration that the monitoring 
technology employed is not inherently incapable of detecting misfire 
under the required conditions (i.e., compliance can be achieved on 
other engines). The evaluation will be based on the following misfire 
patterns: equally spaced misfire occurring on randomly selected 
cylinders; single cylinder continuous misfire; and paired cylinder 
(cylinders firing at the same crank angle) continuous misfire.
    (C) The manufacturer may use monitoring system that has reduced 
misfire detection capability during the portion of the first 1000 
revolutions after engine start that a cold start emission reduction 
strategy is active that reduces engine torque (e.g., spark retard 
strategies). To do so, the manufacturer must demonstrate that the 
probability of detection is greater than or equal to 75 percent during 
the worst case condition (i.e., lowest generated torque) for a vehicle 
operated continuously at idle (park/neutral idle) on a cold start 
between 50 and 86 degrees Fahrenheit and that the technology cannot 
reliably detect a higher percentage of the misfire events during the 
conditions.
    (D) The manufacturer may disable misfire monitoring or use an 
alternative malfunction criterion when misfire cannot be distinguished 
from other effects. To do so, the manufacturer must demonstrate that 
the disablement interval or the period of use of an alternative 
malfunction criterion is limited only to that necessary for avoiding 
false detection and for one or more of the following operating 
conditions: rough road; fuel cut; gear changes for manual transmission 
vehicles; traction control or other vehicle stability control 
activation such as anti-lock braking or other engine torque 
modifications to enhance vehicle stability; off-board control or 
intrusive activation of vehicle components or monitors during service 
or assembly plant testing; portions of intrusive evaporative system or 
EGR monitors that can significantly affect engine stability (i.e., 
while the purge valve is open during the vacuum pull-down of a

[[Page 3303]]

evaporative system leak check but not while the purge valve is closed 
and the evaporative system is sealed or while an EGR monitor causes the 
EGR valve to be cycled intrusively on and off during positive torque 
conditions); or, engine speed, load, or torque transients due to 
throttle movements more rapid than those that occur over the FTP cycle 
for the worst case engine within each engine family. In general, the 
Administrator will not approve disablement for conditions involving 
normal air conditioning compressor cycling from on-to-off or off-to-on, 
automatic transmission gear shifts (except for shifts occurring during 
wide open throttle operation), transitions from idle to off-idle, 
normal engine speed or load changes that occur during the engine speed 
rise time and settling time (i.e., ``flare-up'' and ``flare-down'') 
immediately after engine starting without any vehicle operator-induced 
actions (e.g., throttle stabs), or excess acceleration (except for 
acceleration rates that exceed the maximum acceleration rate obtainable 
at wide open throttle while the vehicle is in gear due to abnormal 
conditions such as slipping of a clutch).
    (iv) MIL activation and DTC storage for engine misfire causing 
catalyst damage.
    (A) Pending DTCs. A pending DTC must be stored immediately if, 
during a single drive cycle, the specified misfire percentage described 
in paragraph (h)(2)(ii)(A) of this section is exceeded three times when 
operating in the positive torque region encountered during a FTP cycle 
or is exceeded on a single occasion when operating at any other engine 
speed and load condition in the positive torque region defined in 
paragraph (h)(2)(iii)(A) of this section. Immediately after a pending 
DTC is stored pursuant to this paragraph, the MIL must blink once per 
second at all times during the drive cycle that engine misfire is 
occurring. The MIL may be deactivated during those times that misfire 
is not occurring. If, at the time that a catalyst damaging misfire 
malfunction occurs, the MIL is already activated for a malfunction 
other than misfire, the MIL must still blink once per second at all 
times during the drive cycle that engine misfire is occurring. If 
misfire ceases, the MIL must stop blinking but remain activated as 
appropriate in accordance with the other malfunction.
    (B) MIL-on DTCs. If a pending DTC is stored in accordance with 
paragraph (h)(2)(iv)(A) of this section, the OBD system must 
immediately store a MIL-on DTC if the percentage of misfire described 
in paragraph (h)(2)(ii)(A) of this section is again exceeded one or 
more times during either the drive cycle immediately following storage 
of the pending DTC, regardless of the conditions encountered during 
that drive cycle, or on the next drive cycle in which similar 
conditions are encountered to those that occurred when the pending DTC 
was stored. If, during a previous drive cycle, a pending DTC is stored 
in accordance with paragraph (h)(2)(iv)(A) of this section, a MIL-on 
DTC must be stored immediately upon exceeding the percentage misfire 
described in paragraph (h)(2)(ii)(A) of this section regardless of the 
conditions encountered. Upon storage of a MIL-on DTC, the MIL must 
blink once per second at all times during the drive cycle that engine 
misfire is occurring. If misfire ceases, the MIL must stop blinking but 
remain activated until the conditions are met for extinguishing the 
MIL.
    (C) Erasure of pending DTCs. Pending DTCs stored in accordance with 
paragraph (h)(2)(iv)(A) of this section must be erased at the end of 
the next drive cycle in which similar conditions are encountered to 
those that occurred when the pending DTC was stored provided no 
exceedances have been detected of the misfire percentage described in 
paragraph (h)(2)(ii)(A) of this section. The pending DTC may also be 
erased if similar conditions are not encountered during the next 80 
drive cycles immediately following storage of the pending DTC.
    (D) Exemptions for engines with fuel shutoff and default fuel 
control. In engines that provide for fuel shutoff and default fuel 
control to prevent over fueling during catalyst damaging misfire 
conditions, the MIL need not blink as required by paragraphs 
(h)(2)(iv)(A) and (h)(2)(iv)(B) of this section. Instead, the MIL may 
be activated continuously upon misfire detection provided that the fuel 
shutoff and default fuel control are activated immediately upon misfire 
detection. Fuel shutoff and default fuel control may be deactivated 
only when the engine is outside of the misfire range except that the 
manufacturer may periodically, but not more than once every 30 seconds, 
deactivate fuel shutoff and default fuel control to determine if the 
catalyst damaging misfire is still occurring. Normal fueling and fuel 
control may be resumed if the catalyst damaging misfire is no longer 
occurring.
    (E) The manufacturer may use a strategy that activates the MIL 
continuously rather than blinking the MIL during extreme catalyst 
damage misfire conditions (i.e., catalyst damage misfire occurring at 
all engine speeds and loads). Use of such a strategy must be limited to 
catalyst damage misfire levels that cannot be avoided during reasonable 
driving conditions. To use such a strategy, the manufacturer must be 
able to demonstrate that the strategy will encourage operation of the 
vehicle in conditions that will minimize catalyst damage (e.g., at low 
engine speeds and loads).
    (v) MIL activation and DTC storage for engine misfire causing 
emissions to exceed applicable emissions thresholds.
    (A) Immediately upon detection, during the first 1000 revolutions 
after engine start of the misfire percentage described in paragraph 
(h)(2)(ii)(B) of this section, a pending DTC must be stored. If such a 
pending DTC is stored already and another such exceedance of the 
misfire percentage is detected within the first 1000 revolutions after 
engine start on any subsequent drive cycle, the MIL must activate and a 
MIL-on DTC must be stored. The pending DTC may be erased if, at the end 
of the next drive cycle in which similar conditions are encountered to 
those that occurred when the pending DTC was stored, there has been no 
exceedance of the misfire percentage described in paragraph 
(h)(2)(ii)(B) of this section. The pending DTC may also be erased if 
similar conditions are not encountered during the next 80 drive cycles 
immediately following storage of the pending DTC.
    (B) No later than the fourth detection during a single drive cycle, 
following the first 1000 revolutions after engine start of the misfire 
percentage described in paragraph (h)(2)(ii)(B) of this section, a 
pending DTC must be stored. If such a pending DTC is stored already, 
then the MIL must activate and a MIL-on DTC must be stored within 10 
seconds of the fourth detection of the misfire percentage described in 
paragraph (h)(2)(ii)(B) of this section during either the drive cycle 
immediately following storage of the pending DTC, regardless of the 
conditions encountered during that drive cycle excepting those 
conditions within the first 1000 revolutions after engine start, or on 
the next drive cycle in which similar conditions are encountered to 
those that occurred when the pending DTC was stored excepting those 
conditions within the first 1000 revolutions after engine start. The 
pending DTC may be erased if, at the end of the next drive cycle in 
which similar conditions are encountered to those that occurred when 
the pending DTC was stored, there has been no exceedance of the misfire 
percentage described in paragraph (h)(2)(ii)(B) of this section. The 
pending DTC may also be erased if

[[Page 3304]]

similar conditions are not encountered during the next 80 drive cycles 
immediately following storage of the pending DTC.
    (vi) Storage of freeze frame conditions for engine misfire.
    (A) The OBD system must store and erase freeze frame conditions (as 
defined in paragraph (k)(4)(iii) of this section) either in conjunction 
with storing and erasing a pending DTC or in conjunction with storing 
and erasing a MIL-on DTC.
    (B) If, upon storage of a DTC as required by paragraphs (h)(2)(iv) 
and (h)(2)(v) of this section, there already exist stored freeze frame 
conditions for a malfunction other than a misfire or fuel system 
malfunction (see paragraph (h)(1) of this section) then the stored 
freeze frame information shall be replaced with freeze frame 
information associated with the misfire malfunction.
    (vii) Storage of engine conditions in association with engine 
misfire. Upon detection of the misfire percentages described in 
paragraphs (h)(2)(ii)(A) and (h)(2)(ii)(B) of this section, the 
following engine conditions must be stored for use in determining 
similar conditions: engine speed, load, and warm up status of the first 
misfire event that resulted in pending DTC storage.
    (viii) MIL deactivation in association with engine misfire. The MIL 
may be deactivated after three sequential drive cycles in which similar 
conditions have been encountered without an exceedance of the misfire 
percentages described in paragraphs (h)(2)(ii)(A) and (h)(2)(ii)(B) of 
this section.
    (3) Exhaust gas recirculation system monitoring.
    (i) General. The OBD system must monitor the EGR system on engines 
so equipped for low and high flow rate malfunctions. The individual 
electronic components (e.g., actuators, valves, sensors) that are used 
in the EGR system must be monitored in accordance with the 
comprehensive component requirements in paragraph (i)(3) of this 
section.
    (ii) EGR system malfunction criteria.
    (A) The OBD system must detect a malfunction of the EGR system 
prior to a decrease from the manufacturer's specified EGR flow rate 
that would cause an engine's emissions to exceed the emissions 
thresholds for ``other monitors'' as shown in Table 2 of this paragraph 
(h). For engines in which no failure or deterioration of the EGR system 
that causes a decrease in flow could result in an engine's emissions 
exceeding the applicable emissions thresholds, the OBD system must 
detect a malfunction when the system has no detectable amount of EGR 
flow.
    (B) The OBD system must detect a malfunction of the EGR system 
prior to an increase from the manufacturer's specified EGR flow rate 
that would cause an engine's emissions to exceed the emissions 
thresholds for ``other monitors'' as shown in Table 2 of this paragraph 
(h). For engines in which no failure or deterioration of the EGR system 
that causes an increase in flow could result in an engine's emissions 
exceeding the applicable emissions thresholds, the OBD system must 
detect a malfunction when the system has reached its control limits 
such that it cannot reduce EGR flow.
    (iii) EGR system monitoring conditions.
    (A) The manufacturer must define the monitoring conditions for 
malfunctions identified in paragraph (h)(3)(ii) of this section in 
accordance with paragraphs (c) and (d) of this section. For purposes of 
tracking and reporting as required by paragraph (d)(1) of this section, 
all monitors used to detect malfunctions identified in paragraph 
(h)(3)(ii) of this section must be tracked separately but reported as a 
single set of values as specified in paragraph (e)(1)(iii) of this 
section.
    (B) The manufacturer may disable temporarily the EGR monitor under 
conditions when monitoring may not be reliable (e.g., when freezing may 
affect performance of the system). To do so, the manufacturer must be 
able to demonstrate that the monitor is unreliable when such conditions 
exist.
    (iv) EGR system MIL activation and DTC storage. The MIL must 
activate and DTCs must be stored according to the provisions of 
paragraph (b) of this section.
    (4) Cold start emission reduction strategy monitoring.
    (i) General. If an engine incorporates a specific engine control 
strategy to reduce cold start emissions, the OBD system must monitor 
the key components (e.g., idle air control valve), other than secondary 
air, while the control strategy is active to ensure proper operation of 
the control strategy.
    (ii) Cold start strategy malfunction criteria.
    (A) The OBD system must detect a malfunction prior to any failure 
or deterioration of the individual components associated with the cold 
start emission reduction control strategy that would cause an engine's 
emissions to exceed the emissions thresholds for ``other monitors'' as 
shown in Table 2 of this paragraph (h). The manufacturer must establish 
the malfunction criteria based on data from one or more representative 
engine(s) and provide an engineering evaluation for establishing the 
malfunction criteria for the remainder of the manufacturer's product 
line.
    (B) Where no failure or deterioration of a component used for the 
cold start emission reduction strategy could result in an engine's 
emissions exceeding the applicable emissions thresholds, the individual 
component must be monitored for proper functional response while the 
control strategy is active in accordance with the malfunction criteria 
in paragraphs (i)(3)(ii) and (i)(3)(iii) of this section.
    (iii) Cold start strategy monitoring conditions. The manufacturer 
must define monitoring conditions for malfunctions identified in 
paragraph (h)(4)(ii) of this section in accordance with paragraphs (c) 
and (d) of this section.
    (iv) Cold start strategy MIL activation and DTC storage. The MIL 
must activate and DTCs must be stored according to the provisions of 
paragraph (b) of this section.
    (5) Secondary air system monitoring.
    (i) General. The OBD system on engines equipped with any form of 
secondary air delivery system must monitor the proper functioning of 
the secondary air delivery system including all air switching 
valves(s). The individual electronic components (e.g., actuators, 
valves, sensors) that are used in the secondary air system must be 
monitored in accordance with the comprehensive component requirements 
in paragraph (i)(3) of this section. For purposes of this paragraph 
(h)(5), ``air flow'' is defined as the air flow delivered by the 
secondary air system to the exhaust system. For engines using secondary 
air systems with multiple air flow paths/distribution points, the air 
flow to each bank (i.e., a group of cylinders that share a common 
exhaust manifold, catalyst, and control sensor) must be monitored in 
accordance with the malfunction criteria in paragraph (h)(5)(ii) of 
this section. Also for purposes of this paragraph (h)(5), ``normal 
operation'' is defined as the condition when the secondary air system 
is activated during catalyst and/or engine warm-up following engine 
start. ``Normal operation'' does not include the condition when the 
secondary air system is turned on intrusively for the sole purpose of 
monitoring.
    (ii) Secondary air system malfunction criteria.
    (A) Except as provided in paragraph (h)(5)(ii)(C) of this section, 
the OBD system must detect a secondary air system malfunction prior to 
a decrease from the manufacturer's specified air

[[Page 3305]]

flow during normal operation that would cause an engine's emissions to 
exceed the emissions thresholds for ``other monitors'' as shown in 
Table 2 of this paragraph (h).
    (B) Except as provided in paragraph (h)(5)(ii)(C) of this section, 
the OBD system must detect a secondary air system malfunction prior to 
an increase from the manufacturer's specified air flow during normal 
operation that would cause an engine's emissions to exceed the 
emissions thresholds for ``other monitors'' as shown in Table 2 of this 
paragraph (h).
    (C) For engines in which no deterioration or failure of the 
secondary air system would result in an engine's emissions exceeding 
the applicable emissions thresholds, the OBD system must detect a 
malfunction when no detectable amount of air flow is delivered by the 
secondary air system during normal operation.
    (iii) Secondary air system monitoring conditions. The manufacturer 
must define monitoring conditions for malfunctions identified in 
paragraph (h)(5)(ii) of this section in accordance with paragraphs (c) 
and (d) of this section. For purposes of tracking and reporting as 
required by paragraph (d)(1) of this section, all monitors used to 
detect malfunctions identified in paragraph (h)(5)(ii) of this section 
must be tracked separately but reported as a single set of values as 
specified in paragraph (e)(1)(iii) of this section.
    (iv) Secondary air system MIL activation and DTC storage. The MIL 
must activate and DTCs must be stored according to the provisions of 
paragraph (b) of this section.
    (6) Catalyst system monitoring.
    (i) General. The OBD system must monitor the catalyst system for 
proper conversion capability.
    (ii) Catalyst system malfunction criteria. The OBD system must 
detect a catalyst system malfunction when the catalyst system's 
conversion capability decreases to the point that emissions exceed the 
emissions thresholds for the catalyst system as shown in Table 2 of 
this paragraph (h).
    (iii) Catalyst system monitoring conditions. The manufacturer must 
define monitoring conditions for malfunctions identified in paragraph 
(h)(6)(ii) of this section in accordance with paragraphs (c) and (d) of 
this section. For purposes of tracking and reporting as required by 
paragraph (d)(1) of this section, all monitors used to detect 
malfunctions identified in paragraph (h)(6)(ii) of this section must be 
tracked separately but reported as a single set of values as specified 
in paragraph (e)(1)(iii) of this section.
    (iv) Catalyst system MIL activation and DTC storage.
    (A) The MIL must activate and DTCs must be stored according to the 
provisions of paragraph (b) of this section.
    (B) The monitoring method for the catalyst system must be capable 
of detecting when a catalyst DTC has been erased (except OBD system 
self erasure), but the catalyst has not been replaced (e.g., catalyst 
overtemperature histogram approaches are not acceptable).
    (7) Evaporative system monitoring.
    (i) General. The OBD system must verify purge flow from the 
evaporative system and monitor the complete evaporative system, 
excluding the tubing and connections between the purge valve and the 
intake manifold, for vapor leaks to the atmosphere. Individual 
components of the evaporative system (e.g., valves, sensors) must be 
monitored in accordance with the comprehensive components requirements 
in paragraph (i)(3) of this section.
    (ii) Evaporative system malfunction criteria.
    (A) Purge monitor. The OBD system must detect an evaporative system 
malfunction when no purge flow from the evaporative system to the 
engine can be detected by the OBD system.
    (B) Leak monitor. The OBD system must detect an evaporative system 
malfunction when the complete evaporative system contains a leak or 
leaks that cumulatively are greater than or equal to a leak caused by a 
0.150 inch diameter hole.
    (C) The manufacturer may demonstrate that detection of a larger 
hole is more appropriate than that specified in paragraph (h)(7)(ii)(B) 
of this section. To do so, the manufacturer must demonstrate through 
data and/or engineering analyses that holes smaller than the proposed 
detection size would not result in evaporative or running loss 
emissions that exceed 1.5 times the applicable evaporative emissions 
standards. Upon such a demonstration, the proposed detection size could 
be substituted for the requirement of paragraph (h)(7)(ii)(B) of this 
section.
    (iii) Evaporative system monitoring conditions.
    (A) The manufacturer must define monitoring conditions for 
malfunctions identified in paragraph (h)(7)(ii)(A) of this section in 
accordance with paragraphs (c) and (d) of this section.
    (B) The manufacturer must define monitoring conditions for 
malfunctions identified in paragraph (h)(7)(ii)(B) of this section in 
accordance with paragraphs (c) and (d) of this section. For purposes of 
tracking and reporting as required by paragraph (d)(1) of this section, 
all monitors used to detect malfunctions identified in paragraph 
(h)(7)(ii)(B) of this section must be tracked separately but reported 
as a single set of values as specified in paragraph (e)(1)(iii) of this 
section.
    (C) The manufacturer may disable or abort an evaporative system 
monitor when the fuel tank level is over 85 percent of nominal tank 
capacity or during a refueling event.
    (D) The manufacturer may request Administrator approval to run the 
evaporative system monitor during only those drive cycles characterized 
as cold starts provided such a condition is needed to ensure reliable 
monitoring. In making the request, the manufacturer must demonstrate 
through data and/or engineering analyses that a reliable monitor can 
only be run on drive cycles that begin with a specific set of cold 
start criteria. A set of cold start criteria based solely on ambient 
temperature exceeding engine coolant temperature will not be 
acceptable.
    (E) The OBD system may disable temporarily the evaporative purge 
system to run an evaporative system leak monitor.
    (iv) Evaporative system MIL activation and DTC storage.
    (A) Except as provided for in paragraph (h)(7)(iv)(B) of this 
section, the MIL must activate and DTCs must be stored according to the 
provisions of paragraph (b) of this section.
    (B) If the OBD system is capable of discerning that a system leak 
is being caused by a missing or improperly secured gas cap, the OBD 
system need not activate the MIL or store a DTC provided the vehicle is 
equipped with an alternative indicator for notifying the operator of 
the gas cap problem. The alternative indicator must be of sufficient 
illumination and location to be readily visible under all lighting 
conditions. If the vehicle is not equipped with such an alternative 
indicator, the MIL must activate and a DTC be stored as required in 
paragraph (h)(7)(iv)(A) of this section; however, these may be 
deactivated and erased, respectively, if the OBD system determines that 
the gas cap problem has been corrected and the MIL has not been 
activated for any other malfunction. The Administrator may approve 
other strategies that provide equivalent assurance that a vehicle 
operator will be notified promptly of a missing or improperly secured 
gas cap and that corrective action will be undertaken.
    (8) Exhaust gas sensor monitoring.
    (i) General.
    (A) The OBD system must monitor for malfunctions the output signal,

[[Page 3306]]

response rate, and any other parameter that can affect emissions of all 
primary (i.e., fuel control) exhaust gas sensors (e.g., oxygen, wide-
range air/fuel). Both the lean-to-rich and rich-to-lean response rates 
must be monitored.
    (B) The OBD system must also monitor all secondary exhaust gas 
sensors (those used for secondary fuel trim control or as a monitoring 
device) for proper output signal, activity, and response rate.
    (C) For engines equipped with heated exhaust gas sensor, the OBD 
system must monitor the heater for proper performance.
    (ii) Primary exhaust gas sensor malfunction criteria.
    (A) The OBD system must detect a malfunction prior to any failure 
or deterioration of the exhaust gas sensor output voltage, resistance, 
impedance, current, response rate, amplitude, offset, or other 
characteristic(s) (including drift or bias corrected for by secondary 
sensors) that would cause an engine's emissions to exceed the emissions 
thresholds for ``other monitors'' as shown in Table 2 of this paragraph 
(h).
    (B) The OBD system must detect malfunctions of the exhaust gas 
sensor caused by either a lack of circuit continuity or out-of-range 
values.
    (C) The OBD system must detect a malfunction of the exhaust gas 
sensor when a sensor failure or deterioration causes the fuel system to 
stop using that sensor as a feedback input (e.g., causes default or 
open-loop operation).
    (D) The OBD system must detect a malfunction of the exhaust gas 
sensor when the sensor output voltage, resistance, impedance, current, 
amplitude, activity, or other characteristics are no longer sufficient 
for use as an OBD system monitoring device (e.g., for catalyst 
monitoring).
    (iii) Secondary exhaust gas sensor malfunction criteria.
    (A) The OBD system must detect a malfunction prior to any failure 
or deterioration of the exhaust gas sensor voltage, resistance, 
impedance, current, response rate, amplitude, offset, or other 
characteristic(s) that would cause an engine's emissions to exceed the 
emissions thresholds for ``other monitors'' as shown in Table 2 of this 
paragraph (h).
    (B) The OBD system must detect malfunctions of the exhaust gas 
sensor caused by a lack of circuit continuity.
    (C) To the extent feasible, the OBD system must detect a 
malfunction of the exhaust gas sensor when the sensor output voltage, 
resistance, impedance, current, amplitude, activity, offset, or other 
characteristics are no longer sufficient for use as an OBD system 
monitoring device (e.g., for catalyst monitoring).
    (D) The OBD system must detect malfunctions of the exhaust gas 
sensor caused by out-of-range values.
    (E) The OBD system must detect a malfunction of the exhaust gas 
sensor when a sensor failure or deterioration causes the fuel system 
(e.g., fuel control) to stop using that sensor as a feedback input 
(e.g., causes default or open-loop operation).
    (iv) Exhaust gas sensor heater malfunction criteria.
    (A) The OBD system must detect a malfunction of the heater 
performance when the current or voltage drop in the heater circuit is 
no longer within the manufacturer's specified limits for normal 
operation (i.e., within the criteria required to be met by the 
component vendor for heater circuit performance at high mileage). Other 
malfunction criteria for heater performance malfunctions may be used 
upon demonstrating via data or engineering analyses that the monitoring 
reliability and timeliness is equivalent to the stated criteria in this 
paragraph (h)(8)(iv)(A).
    (B) The OBD system must detect malfunctions of the heater circuit 
including open or short circuits that conflict with the commanded state 
of the heater (e.g., shorted to 12 Volts when commanded to 0 Volts 
(ground)).
    (v) Primary exhaust gas sensor monitoring conditions.
    (A) The manufacturer must define monitoring conditions for 
malfunctions identified in paragraphs (h)(8)(ii)(A) and (h)(8)(ii)(D) 
of this section in accordance with paragraphs (c) and (d) of this 
section. For purposes of tracking and reporting as required by 
paragraph (d)(1) of this section, all monitors used to detect 
malfunctions identified in paragraphs (h)(8)(ii)(A) and (h)(8)(ii)(D) 
of this section must be tracked separately but reported as a single set 
of values as specified in paragraph (e)(1)(iii) of this section.
    (B) Except as provided for in paragraph (h)(8)(v)(C) of this 
section, monitoring for malfunctions identified in paragraphs 
(h)(8)(ii)(B) and (h)(8)(ii)(C) of this section must be conducted 
continuously.
    (C) The manufacturer may disable continuous primary exhaust gas 
sensor monitoring when a primary exhaust gas sensor malfunction cannot 
be distinguished from other effects (e.g., disable out-of-range low 
monitoring during fuel cut conditions). To do so, the manufacturer must 
demonstrate via data or engineering analyses that a properly 
functioning sensor cannot be distinguished from a malfunctioning sensor 
and that the disablement interval is limited only to that necessary for 
avoiding false detection.
    (vi) Secondary exhaust gas sensor monitoring conditions.
    (A) The manufacturer must define monitoring conditions for 
malfunctions identified in paragraphs (h)(8)(iii)(A) through 
(h)(8)(iii)(C) of this section in accordance with paragraphs (c) and 
(d) of this section.
    (B) Except as provided for in paragraph (h)(8)(vi)(C) of this 
section, monitoring for malfunctions identified in paragraphs 
(h)(8)(iii)(D) and (h)(8)(iii)(E) of this section must be conducted 
continuously.
    (C) The manufacturer may disable continuous secondary exhaust gas 
sensor monitoring when a secondary exhaust gas sensor malfunction 
cannot be distinguished from other effects (e.g., disable out-of-range 
low monitoring during fuel cut conditions). To do so, the manufacturer 
must demonstrate via data or engineering analyses that a properly 
functioning sensor cannot be distinguished from a malfunctioning sensor 
and that the disablement interval is limited only to that necessary for 
avoiding false detection.
    (vii) Exhaust gas sensor heater monitoring conditions.
    (A) The manufacturer must define monitoring conditions for 
malfunctions identified in paragraph (h)(8)(iv)(A) of this section in 
accordance with paragraphs (c) and (d) of this section.
    (B) Monitoring for malfunctions identified in paragraph 
(h)(8)(iv)(B) of this section must be conducted continuously.
    (viii) Exhaust gas sensor MIL activation and DTC storage. The MIL 
must activate and DTCs must be stored according to the provisions of 
paragraph (b) of this section.
    (9) Variable valve timing (VVT) system monitoring.
    (i) General. The OBD system must monitor the VVT system on engines 
so equipped for target error and slow response malfunctions. The 
individual electronic components (e.g., actuators, valves, sensors) 
that are used in the VVT system must be monitored in accordance with 
the comprehensive components requirements in paragraph (i)(3) of this 
section.
    (ii) VVT system malfunction criteria.
    (A) VVT system target error. The OBD system must detect a 
malfunction prior to any failure or deterioration in the capability of 
the VVT system to achieve the commanded valve timing and/or control 
within a crank angle and/or lift tolerance that would cause an engine's 
emissions to exceed the emission

[[Page 3307]]

thresholds for ``other monitors'' as shown in Table 2 of this paragraph 
(h).
    (B) VVT slow response. The OBD system must detect a malfunction 
prior to any failure or deterioration in the capability of the VVT 
system to achieve the commanded valve timing and/or control within a 
manufacturer-specified time that would cause an engine's emissions to 
exceed the emission thresholds for ``other monitors'' as shown in Table 
2 of this paragraph (h).
    (C) For engines in which no failure or deterioration of the VVT 
system could result in an engine's emissions exceeding the applicable 
emissions thresholds of paragraphs (h)(9)(ii)(A) and (h)(9)(ii)(B) of 
this paragraph (h), the OBD system must detect a malfunction of the VVT 
system when proper functional response of the system to computer 
commands does not occur.
    (iii) VVT system monitoring conditions. Manufacturers must define 
the monitoring conditions for VVT system malfunctions identified in 
paragraph (h)(9)(ii) of this section in accordance with paragraphs (c) 
and (d) of this section, with the exception that monitoring must occur 
every time the monitoring conditions are met during the drive cycle 
rather than once per drive cycle as required in paragraph (c)(2) of 
this section. For purposes of tracking and reporting as required in 
paragraph (d)(1) of this section, all monitors used to detect 
malfunctions identified in paragraph (h)(9)(ii) of this section must be 
tracked separately but reported as a single set of values as specified 
in paragraph (e)(1)(iii) of this section.
    (iv) VVT MIL activation and DTC storage. The MIL must activate and 
DTCs must be stored according to the provisions of paragraph (b) of 
this section.
    (i) OBD monitoring requirements for all engines.
    (1) Engine cooling system monitoring.
    (i) General.
    (A) The OBD system must monitor the thermostat on engines so 
equipped for proper operation.
    (B) The OBD system must monitor the engine coolant temperature 
(ECT) sensor for electrical circuit continuity, out-of-range values, 
and rationality malfunctions.
    (C) For engines that use a system other than the cooling system and 
ECT sensor (e.g., oil temperature, cylinder head temperature) to 
determine engine operating temperature for emission control purposes 
(e.g., to modify spark or fuel injection timing or quantity), the 
manufacturer may forego cooling system monitoring and instead monitor 
the components or systems used in their approach. To do so, the 
manufacturer must to submit data and/or engineering analyses that 
demonstrate that their monitoring plan is as reliable and effective as 
the monitoring required in this paragraph (i)(1).
    (ii) Malfunction criteria for the thermostat.
    (A) The OBD system must detect a thermostat malfunction if, within 
the manufacturer specified time interval following engine start, any of 
the following conditions occur: the coolant temperature does not reach 
the highest temperature required by the OBD system to enable other 
diagnostics; and, the coolant temperature does not reach a warmed-up 
temperature within 20 degrees Fahrenheit of the manufacturer's nominal 
thermostat regulating temperature. For the second of these two 
conditions, the manufacturer may use a lower temperature for this 
criterion provided the manufacturer can demonstrate that the fuel, 
spark timing, and/or other coolant temperature-based modification to 
the engine control strategies would not cause an emissions increase 
greater than or equal to 50 percent of any of the applicable emissions 
standards.
    (B) The manufacturer may use alternative malfunction criteria to 
those of paragraph (i)(1)(ii)(A) of this section and/or alternative 
monitoring conditions to those of paragraph (i)(1)(iv) of this section 
that are a function of temperature at engine start on engines that do 
not reach the temperatures specified in the malfunction criteria when 
the thermostat is functioning properly. To do so, the manufacturer is 
required to submit data and/or engineering analyses that demonstrate 
that a properly operating system does not reach the specified 
temperatures and that the possibility is minimized for cooling system 
malfunctions to go undetected thus disabling other OBD monitors.
    (C) The manufacturer may request Administrator approval to forego 
monitoring of the thermostat if the manufacturer can demonstrate that a 
malfunctioning thermostat cannot cause a measurable increase in 
emissions during any reasonable driving condition nor cause any 
disablement of other OBD monitors.
    (iii) Malfunction criteria for the ECT sensor.
    (A) Circuit integrity. The OBD system must detect malfunctions of 
the ECT sensor related to a lack of circuit continuity or out-of-range 
values.
    (B) Time to reach closed-loop/feedback enable temperature. The OBD 
system must detect if, within the manufacturer specified time interval 
following engine start, the ECT sensor does not achieve the highest 
stabilized minimum temperature that is needed to initiate closed-loop/
feedback control of all affected emission control systems (e.g., fuel 
system, EGR system). The manufacturer specified time interval must be a 
function of the engine coolant temperature and/or intake air 
temperature at startup. The manufacturer time interval must be 
supported by data and/or engineering analyses demonstrating that it 
provides robust monitoring and minimizes the likelihood of other OBD 
monitors being disabled. The manufacturer may forego the requirements 
of this paragraph (i)(1)(iii)(B) provided the manufacturer does not use 
engine coolant temperature or the ECT sensor to enable closed-loop/
feedback control of any emission control systems.
    (C) Stuck in range below the highest minimum enable temperature. To 
the extent feasible when using all available information, the OBD 
system must detect a malfunction if the ECT sensor inappropriately 
indicates a temperature below the highest minimum enable temperature 
required by the OBD system to enable other monitors (e.g., an OBD 
system that requires ECT to be greater than 140 degrees Fahrenheit to 
enable a diagnostic must detect malfunctions that cause the ECT sensor 
to inappropriately indicate a temperature below 140 degrees 
Fahrenheit). The manufacturer may forego this requirement for 
temperature regions in which the monitors required under paragraphs 
(i)(1)(ii) or (i)(1)(iii)(B) of this section will detect ECT sensor 
malfunctions as defined in this paragraph (i)(1)(iii)(C).
    (D) Stuck in range above the lowest maximum enable temperature. The 
OBD system must detect a malfunction if the ECT sensor inappropriately 
indicates a temperature above the lowest maximum enable temperature 
required by the OBD system to enable other monitors (e.g., an OBD 
system that requires an engine coolant temperature less than 90 degrees 
Fahrenheit at startup prior to enabling an OBD monitor must detect 
malfunctions that cause the ECT sensor to indicate inappropriately a 
temperature above 90 degrees Fahrenheit). The manufacturer may forego 
this requirement within temperature regions in which the monitors 
required under paragraphs (i)(1)(ii), (i)(1)(iii)(B), and 
(i)(1)(iii)(C) of this section will detect ECT sensor malfunctions as 
defined in this paragraph (i)(1)(iii)(D) or in which the MIL will be 
activated according to the provisions of paragraph (b)(2)(v) of this

[[Page 3308]]

section. The manufacturer may also forego this monitoring within 
temperature regions where a temperature gauge on the instrument panel 
indicates a temperature in the ``red zone'' (engine overheating zone) 
and displays the same temperature information as used by the OBD 
system.
    (iv) Monitoring conditions for the thermostat.
    (A) The manufacturer must define the monitoring conditions for 
malfunctions identified in paragraph (i)(1)(ii)(A) of this section in 
accordance with paragraph (c) of this section. Additionally, except as 
provided for in paragraphs (i)(1)(iv)(B) and (i)(1)(iv)(C) of this 
section, monitoring for malfunctions identified in paragraph 
(i)(1)(ii)(A) of this section must be conducted once per drive cycle on 
every drive cycle in which the ECT sensor indicates, at engine start, a 
temperature lower than the temperature established as the malfunction 
criteria in paragraph (i)(1)(ii)(A) of this section.
    (B) The manufacturer may disable thermostat monitoring at ambient 
engine start temperatures below 20 degrees Fahrenheit.
    (C) The manufacturer may request Administrator approval to suspend 
or disable thermostat monitoring if the engine is subjected to 
conditions that could lead to false diagnosis. To do so, the 
manufacturer must submit data and/or engineering analyses that 
demonstrate that the suspension or disablement is necessary. In 
general, the manufacturer will not be allowed to suspend or disable the 
thermostat monitor on engine starts where the engine coolant 
temperature at engine start is more than 35 degrees Fahrenheit lower 
than the thermostat malfunction threshold temperature determined under 
paragraph (i)(1)(ii)(A) of this paragraph (i)(1).
    (v) Monitoring conditions for the ECT sensor.
    (A) Except as provided for in paragraph (i)(1)(v)(E) of this 
section, the OBD system must monitor continuously for malfunctions 
identified in paragraph (i)(1)(iii)(A) of this section (i.e., circuit 
integrity and out-of-range).
    (B) The manufacturer must define the monitoring conditions for 
malfunctions identified in paragraph (i)(1)(iii)(B) of this section in 
accordance with paragraph (c) of this section. Additionally, except as 
provided for in paragraph (i)(1)(v)(D) of this section, monitoring for 
malfunctions identified in paragraph (i)(1)(iii)(B) of this section 
must be conducted once per drive cycle on every drive cycle in which 
the ECT sensor indicates a temperature lower than the closed-loop 
enable temperature at engine start (i.e., all engine start temperatures 
greater than the ECT sensor out-of-range low temperature and less than 
the closed-loop enable temperature).
    (C) The manufacturer must define the monitoring conditions for 
malfunctions identified in paragraphs (i)(1)(iii)(C) and (i)(1)(iii)(D) 
of this section in accordance with paragraphs (c) and (d) of this 
section.
    (D) The manufacturer may suspend or delay the monitor for the time 
to reach closed-loop enable temperature if the engine is subjected to 
conditions that could lead to false diagnosis (e.g., vehicle operation 
at idle for more than 50 to 75 percent of the warm-up time).
    (E) The manufacturer may request Administrator approval to disable 
continuous ECT sensor monitoring when an ECT sensor malfunction cannot 
be distinguished from other effects. To do so, the manufacturer must 
submit data and/or engineering analyses that demonstrate a properly 
functioning sensor cannot be distinguished from a malfunctioning sensor 
and that the disablement interval is limited only to that necessary for 
avoiding false detection.
    (vi) Engine cooling system MIL activation and DTC storage. The MIL 
must activate and DTCs must be stored according to the provisions of 
paragraph (b) of this section.
    (2) Crankcase ventilation (CV) system monitoring.
    (i) General. The OBD system must monitor the CV system on engines 
so equipped for system integrity. Engines not required to be equipped 
with CV systems are exempt from monitoring the CV system. For diesel 
engines, the manufacturer must submit a plan for Administrator prior to 
OBD certification. That plan must include descriptions of the 
monitoring strategy, malfunction criteria, and monitoring conditions 
for CV system monitoring. The plan must demonstrate that the CV system 
monitor is of equivalent effectiveness, to the extent feasible, to the 
malfunction criteria and the monitoring conditions of this paragraph 
(i)(2).
    (ii) Crankcase ventilation system malfunction criteria.
    (A) For the purposes of this paragraph (i)(2), ``CV system'' is 
defined as any form of crankcase ventilation system, regardless of 
whether it utilizes positive pressure. ``CV valve'' is defined as any 
form of valve or orifice used to restrict or control crankcase vapor 
flow. Further, any additional external CV system tubing or hoses used 
to equalize crankcase pressure or to provide a ventilation path between 
various areas of the engine (e.g., crankcase and valve cover) are 
considered part of the CV system ``between the crankcase and the CV 
valve'' and subject to the malfunction criteria in paragraph 
(i)(2)(ii)(B) of this section.
    (B) Except as provided for in paragraphs (i)(2)(ii)(C) through 
(i)(2)(ii)(E) of this section, the OBD system must detect a malfunction 
of the CV system when a disconnection of the system occurs between 
either the crankcase and the CV valve, or between the CV valve and the 
intake manifold.
    (C) The manufacturer may forego monitoring for a disconnection 
between the crankcase and the CV valve provided the CV system is 
designed such that the CV valve is fastened directly to the crankcase 
such that it is significantly more difficult to remove the CV valve 
from the crankcase than to disconnect the line between the CV valve and 
the intake manifold (taking aging effects into consideration). To do 
so, the manufacturer must be able to provide data and/or an engineering 
evaluation demonstrating that the CV system is so designed.
    (D) The manufacturer may forego monitoring for a disconnection 
between the crankcase and the CV valve provided the CV system is 
designed such that it uses tubing connections between the CV valve and 
the crankcase that are: resistant to deterioration or accidental 
disconnection; significantly more difficult to disconnect than is the 
line between the CV valve and the intake manifold; and, not subject to 
disconnection per the manufacturer's repair procedures for any non-CV 
system repair. To do so, the manufacturer must be able to provide data 
and/or engineering evaluation demonstrating that the CV system is so 
designed.
    (E) The manufacturer may forego monitoring for a disconnection 
between the CV valve and the intake manifold provided the CV system is 
designed such that any disconnection either causes the engine to stall 
immediately during idle operation, or is unlikely to occur due to a CV 
system design that is integral to the induction system (e.g., machined 
passages rather than tubing or hoses). To do so, the manufacturer must 
be able to provide data and/or an engineering evaluation demonstrating 
that the CV system is so designed.
    (iii) Crankcase ventilation system monitoring conditions. The 
manufacturer must define the monitoring conditions for malfunctions 
identified in paragraph (i)(2) of this section in accordance with 
paragraphs (c) and (d) of this section.

[[Page 3309]]

    (iv) Crankcase ventilation system MIL activation and DTC storage. 
The MIL must activate and DTCs must be stored according to the 
provisions of paragraph (b) of this section. The stored DTC need not 
identify specifically the CV system (e.g., a DTC for idle speed control 
or fuel system monitoring can be stored) if the manufacturer can 
demonstrate that additional monitoring hardware is necessary to make 
such an identification and provided the manufacturer's diagnostic and 
repair procedures for the detected malfunction include directions to 
check the integrity of the CV system.
    (3) Comprehensive component monitoring.
    (i) General. Except as provided for in paragraph (i)(4) of this 
section, the OBD system must detect a malfunction of any electronic 
engine component or system not otherwise described in paragraphs (g), 
(h), (i)(1), and (i)(2) of this section that either provides input to 
(directly or indirectly, such components may include the crank angle 
sensor, knock sensor, throttle position sensor, cam position sensor, 
intake air temperature sensor, boost pressure sensor, manifold pressure 
sensor, mass air flow sensor, exhaust temperature sensor, exhaust 
pressure sensor, fuel pressure sensor, fuel composition sensor of a 
flexible fuel vehicle, etc.) or receives commands from (such components 
or systems may include the idle speed control system, glow plug system, 
variable length intake manifold runner systems, supercharger or 
turbocharger electronic components, heated fuel preparation systems, 
the wait-to-start lamp on diesel applications, the MIL, etc.) the 
onboard computer(s) and meets either of the criteria described in 
paragraphs (i)(3)(i)(A) and/or (i)(3)(i)(B) of this section. Note that, 
for the purposes of this paragraph (i)(3), ``electronic engine 
component or system'' does not include components that are driven by 
the engine and are not related to the control of the fueling, air 
handling, or emissions of the engine (e.g., power take-off (PTO) 
components, air conditioning system components, and power steering 
components).
    (A) It can affect emissions during any reasonable in-use driving 
condition. The manufacturer must be able to provide emission data 
showing that the component or system, when malfunctioning and installed 
on a suitable test engine, does not have an emission effect.
    (B) It is used as part of the monitoring strategy for any other 
monitored system or component.
    (ii) Comprehensive component malfunction criteria for input 
components.
    (A) The OBD system must detect malfunctions of input components 
caused by a lack of circuit continuity and out-of-range values. In 
addition, where feasible, rationality checks must also be done and 
shall verify that a sensor output is neither inappropriately high nor 
inappropriately low (i.e., ``two-sided'' monitoring).
    (B) To the extent feasible, the OBD system must separately detect 
and store different DTCs that distinguish rationality malfunctions from 
lack of circuit continuity and out-of-range malfunctions. For lack of 
circuit continuity and out-of-range malfunctions, the OBD system must, 
to the extent feasible, separately detect and store different DTCs for 
each distinct malfunction (e.g., out-of-range low, out-of-range high, 
open circuit). The OBD system is not required to store separate DTCs 
for lack of circuit continuity malfunctions that cannot be 
distinguished from other out-of-range circuit malfunctions.
    (C) For input components that are used to activate alternative 
strategies that can affect emissions (e.g., AECDs, engine shutdown 
systems), the OBD system must conduct rationality checks to detect 
malfunctions that cause the system to activate erroneously or 
deactivate the alternative strategy. To the extent feasible when using 
all available information, the rationality check must detect a 
malfunction if the input component inappropriately indicates a value 
that activates or deactivates the alternative strategy. For example, 
for an alternative strategy that activates when the intake air 
temperature is greater than 120 degrees Fahrenheit, the OBD system must 
detect malfunctions that cause the intake air temperature sensor to 
indicate inappropriately a temperature above 120 degrees Fahrenheit.
    (D) For engines that require precise alignment between the camshaft 
and the crankshaft, the OBD system must monitor the crankshaft position 
sensor(s) and camshaft position sensor(s) to verify proper alignment 
between the camshaft and crankshaft in addition to monitoring the 
sensors for circuit continuity and proper rationality. Proper alignment 
monitoring between a camshaft and a crankshaft is required only in 
cases where both are equipped with position sensors. For engines 
equipped with VVT systems and a timing belt or chain, the OBD system 
must detect a malfunction if the alignment between the camshaft and 
crankshaft is off by one or more cam/crank sprocket cogs (e.g., the 
timing belt/chain has slipped by one or more teeth/cogs). If a 
manufacturer demonstrates that a single tooth/cog misalignment cannot 
cause a measurable increase in emissions during any reasonable driving 
condition, the OBD system must detect a malfunction when the minimum 
number of teeth/cogs misalignment has occurred that does cause a 
measurable emission increase.
    (iii) Comprehensive component malfunction criteria for output 
components/systems.
    (A) The OBD system must detect a malfunction of an output 
component/system when proper functional response does not occur in 
response to computer commands. If such a functional check is not 
feasible, the OBD system must detect malfunctions of output components/
systems caused by a lack of circuit continuity or circuit malfunction 
(e.g., short to ground or high voltage). For output component lack of 
circuit continuity malfunctions and circuit malfunctions, the OBD 
system is not required to store different DTCs for each distinct 
malfunction (e.g., open circuit, shorted low). Manufacturers are not 
required to activate an output component/system when it would not 
normally be active for the sole purpose of performing a functional 
check of it as required in this paragraph (i)(3).
    (B) For gasoline engines, the idle control system must be monitored 
for proper functional response to computer commands. For gasoline 
engines using monitoring strategies based on deviation from target idle 
speed, a malfunction must be detected when either of the following 
conditions occurs: the idle speed control system cannot achieve the 
target idle speed within 200 revolutions per minute (rpm) above the 
target speed or 100 rpm below the target speed; or, the idle speed 
control system cannot achieve the target idle speed within the smallest 
engine speed tolerance range required by the OBD system to enable any 
other monitors. Regarding the former of these conditions, the 
manufacturer may use larger engine speed tolerances. To do so, the 
manufacturer must be able to provide data and/or engineering analyses 
that demonstrate that the tolerances can be exceeded without a 
malfunction being present.
    (C) For diesel engines, the idle control system must be monitored 
for proper functional response to computer commands. For diesel 
engines, a malfunction must be detected when either of the following 
conditions occurs: the idle fuel control system cannot achieve the 
target idle speed or fuel injection quantity within 50 
percent of the manufacturer-specified fuel quantity and engine speed

[[Page 3310]]

tolerances; or, the idle fuel control system cannot achieve the target 
idle speed or fueling quantity within the smallest engine speed or 
fueling quantity tolerance range required by the OBD system to enable 
any other monitors.
    (D) Glow plugs/intake air heater systems must be monitored for 
proper functional response to computer commands and for circuit 
continuity malfunctions. The glow plug/intake air heater circuit(s) 
must be monitored for proper current and voltage drop. The manufacturer 
may use other monitoring strategies but must be able to provide data 
and/or engineering analyses that demonstrate reliable and timely 
detection of malfunctions. The OBD system must also detect a 
malfunction when a single glow plug no longer operates within the 
manufacturer's specified limits for normal operation. If a manufacturer 
can demonstrate that a single glow plug malfunction cannot cause a 
measurable increase in emissions during any reasonable driving 
condition, the OBD system must instead detect a malfunction when the 
number of glow plugs needed to cause an emission increase is 
malfunctioning. To the extent feasible, the stored DTC must identify 
the specific malfunctioning glow plug(s).
    (E) The wait-to-start lamp circuit and the MIL circuit must be 
monitored for malfunctions that cause either lamp to fail to activate 
when commanded to do so (e.g., burned out bulb).
    (iv) Monitoring conditions for input components.
    (A) The OBD system must monitor input components continuously for 
out-of-range values and circuit continuity. The manufacturer may 
disable continuous monitoring for circuit continuity and out-of-range 
values when a malfunction cannot be distinguished from other effects. 
To do so, the manufacturer must be able to provide data and/or 
engineering analyses that demonstrate that a properly functioning input 
component cannot be distinguished from a malfunctioning input component 
and that the disablement interval is limited only to that necessary for 
avoiding false malfunction detection.
    (B) For input component rationality checks (where applicable), the 
manufacturer must define the monitoring conditions for detecting 
malfunctions in accordance with paragraphs (c) and (d) of this section, 
with the exception that rationality checks must occur every time the 
monitoring conditions are met during the drive cycle rather than once 
per drive cycle as required in paragraph (c)(2) of this section.
    (v) Monitoring conditions for output components/systems.
    (A) The OBD system must monitor output components/systems 
continuously for circuit continuity and circuit malfunctions. The 
manufacturer may disable continuous monitoring for circuit continuity 
and circuit malfunctions when a malfunction cannot be distinguished 
from other effects. To do so, the manufacturer must be able to provide 
data and/or engineering analyses that demonstrate that a properly 
functioning output component/system cannot be distinguished from a 
malfunctioning one and that the disablement interval is limited only to 
that necessary for avoiding false malfunction detection.
    (B) For output component/system functional checks, the manufacturer 
must define the monitoring conditions for detecting malfunctions in 
accordance with paragraphs (c) and (d) of this section. Specifically 
for the idle control system, the manufacturer must define the 
monitoring conditions for detecting malfunctions in accordance with 
paragraphs (c) and (d) of this section, with the exception that 
functional checks must occur every time the monitoring conditions are 
met during the drive cycle rather than once per drive cycle as required 
in paragraph (c)(2) of this section.
    (vi) Comprehensive component MIL activation and DTC storage.
    (A) Except as provided for in paragraphs (i)(3)(vi)(B) and 
(i)(3)(vi)(C) of this section, the MIL must activate and DTCs must be 
stored according to the provisions of paragraph (b) of this section.
    (B) The MIL need not be activated in conjunction with storing a 
MIL-on DTC for any comprehensive component if: the component or system, 
when malfunctioning, could not cause engine emissions to increase by 15 
percent or more of the applicable FTP standard during any reasonable 
driving condition; or, the component or system is not used as part of 
the monitoring strategy for any other system or component that is 
required to be monitored.
    (C) The MIL need not be activated if a malfunction has been 
detected in the MIL circuit that prevents the MIL from activating 
(e.g., burned out bulb or light-emitting diode, LED). Nonetheless, the 
electronic MIL status (see paragraph (k)(4)(ii) of this section) must 
be reported as MIL commanded-on and a MIL-on DTC must be stored.
    (4) Other emission control system monitoring.
    (i) General. For other emission control systems that are either not 
addressed in paragraphs (g) through (i)(3) of this section (e.g., 
hydrocarbon traps, homogeneous charge compression ignition control 
systems), or addressed in paragraph (i)(3) of this section but not 
corrected or compensated for by an adaptive control system (e.g., swirl 
control valves), the manufacturer must submit a plan for Administrator 
approval of the monitoring strategy, malfunction criteria, and 
monitoring conditions prior to introduction on a production engine. The 
plan must demonstrate the effectiveness of the monitoring strategy, the 
malfunction criteria used, the monitoring conditions required by the 
monitor, and, if applicable, the determination that the requirements of 
paragraph (i)(4)(ii) of this section are satisfied.
    (ii) For engines that use emission control systems that alter 
intake air flow or cylinder charge characteristics by actuating 
valve(s), flap(s), etc., in the intake air delivery system (e.g., swirl 
control valve systems), the manufacturer, in addition to meeting the 
requirements of paragraph (i)(4)(i) of this section, may elect to have 
the OBD system monitor the shaft to which all valves in one intake bank 
are physically attached rather than performing a functional check of 
the intake air flow, cylinder charge, or individual valve(s)/flap(s). 
For non-metal shafts or segmented shafts, the monitor must verify all 
shaft segments for proper functional response (e.g., by verifying that 
the segment or portion of the shaft farthest from the actuator 
functions properly). For systems that have more than one shaft to 
operate valves in multiple intake banks, the manufacturer is not 
required to add more than one set of detection hardware (e.g., sensor, 
switch) per intake bank to meet this requirement.
    (5) Exceptions to OBD monitoring requirements.
    (i) The Administrator may revise the PM filtering performance 
malfunction criteria for DPFs to exclude detection of specific failure 
modes such as partially melted substrates, if the most reliable 
monitoring method developed requires it.
    (ii) The manufacturer may disable an OBD system monitor at ambient 
engine start temperatures below 20 degrees Fahrenheit (low ambient 
temperature conditions may be determined based on intake air or engine 
coolant temperature at engine start) or at elevations higher than 8,000 
feet above sea level. To do so, the manufacturer must submit data and/
or engineering analyses that demonstrate that monitoring is

[[Page 3311]]

unreliable during the disable conditions. A manufacturer may request 
that an OBD system monitor be disabled at other ambient engine start 
temperatures by submitting data and/or engineering analyses 
demonstrating that misdiagnosis would occur at the given ambient 
temperatures due to their effect on the component itself (e.g., 
component freezing).
    (iii) The manufacturer may disable an OBD system monitor when the 
fuel level is 15 percent or less of the nominal fuel tank capacity for 
those monitors that can be affected by low fuel level or running out of 
fuel (e.g., misfire detection). To do so, the manufacturer must submit 
data and/or engineering analyses that demonstrate that monitoring at 
the given fuel levels is unreliable, and that the OBD system is still 
able to detect a malfunction if the component(s) used to determine fuel 
level indicates erroneously a fuel level that causes the disablement.
    (iv) The manufacturer may disable OBD monitors that can be affected 
by engine battery or system voltage levels.
    (A) For an OBD monitor affected by low vehicle battery or system 
voltages, manufacturers may disable monitoring when the battery or 
system voltage is below 11.0 Volts. The manufacturer may use a voltage 
threshold higher than 11.0 Volts to disable monitors but must submit 
data and/or engineering analyses that demonstrate that monitoring at 
those voltages is unreliable and that either operation of a vehicle 
below the disablement criteria for extended periods of time is unlikely 
or the OBD system monitors the battery or system voltage and will 
detect a malfunction at the voltage used to disable other monitors.
    (B) For an OBD monitor affected by high engine battery or system 
voltages, the manufacturer may disable monitoring when the battery or 
system voltage exceeds a manufacturer-defined voltage. To do so, the 
manufacturer must submit data and/or engineering analyses that 
demonstrate that monitoring above the manufacturer-defined voltage is 
unreliable and that either the electrical charging system/alternator 
warning light will be activated (or voltage gauge would be in the ``red 
zone'') or the OBD system monitors the battery or system voltage and 
will detect a malfunction at the voltage used to disable other 
monitors.
    (v) The manufacturer may also disable affected OBD monitors in 
systems designed to accommodate the installation of power take off 
(PTO) units provided monitors are disabled only while the PTO unit is 
active and the OBD readiness status (see paragraph (k)(4)(i) of this 
section) is cleared by the onboard computer (i.e., all monitors set to 
indicate ``not complete'' or ``not ready'') while the PTO unit is 
activated. If monitors are so disabled and when the disablement ends, 
the readiness status may be restored to its state prior to PTO 
activation.
    (6) Feedback control system monitoring. If the engine is equipped 
with feedback control of any of the systems covered in paragraphs (g), 
(h) and (i) of this section, then the OBD system must detect as 
malfunctions the conditions specified in this paragraph (i)(6) for each 
of the individual feedback controls.
    (i) The OBD system must detect when the system fails to begin 
feedback control within a manufacturer specified time interval.
    (ii) When any malfunction or deterioration causes open loop or 
limp-home operation.
    (iii) When feedback control has used up all of the adjustment 
allowed by the manufacturer.
    (iv) A manufacturer may temporarily disable monitoring for 
malfunctions specified in paragraph (i)(6)(iii) of this section during 
conditions that the specific monitor cannot distinguish robustly 
between a malfunctioning system and a properly operating system. To do 
so, the manufacturer is required to submit data and/or engineering 
analyses demonstrating that the individual feedback control system, 
when operating as designed on an engine with all emission controls 
working properly, routinely operates during these conditions while 
having used up all of the adjustment allowed by the manufacturer. In 
lieu of detecting, with a system specific monitor, the malfunctions 
specified in paragraphs (i)(6)(i) and (i)(6)(ii) of this section the 
OBD system may monitor the individual parameters or components that are 
used as inputs for individual feedback control systems provided that 
the monitors detect all malfunctions that meet the criteria of 
paragraphs (i)(6)(i) and (i)(6)(ii) of this section.
    (a) Production evaluation testing.
    (1) [Reserved.]
    (2) Verification of monitoring requirements.
    (i) Within either the first six months of the start of engine 
production or the first three months of the start of vehicle 
production, whichever is later, the manufacturer must conduct a 
complete evaluation of the OBD system of one or more production 
vehicles (test vehicles) and submit the results of the evaluation to 
the Administrator.
    (ii) Selection of test vehicles.
    (A) For each engine selected for monitoring system demonstration in 
paragraph (l) of this section, the manufacturer must evaluate one 
production vehicle equipped with an engine from the same engine family 
and rating as the demonstration engine. The vehicle selection must be 
approved by the Administrator.
    (B) If the manufacturer is required to test more than one test 
vehicle, the manufacturer may test an engine in lieu of a vehicle for 
all but one of the required test vehicles.
    (C) The requirement for submittal of data from one or more of the 
test vehicles may be waived if data have been submitted previously for 
all of the engine ratings and variants.
    (iii) Evaluation requirements.
    (A) The evaluation must demonstrate the ability of the OBD system 
on the selected test vehicle to detect a malfunction, activate the MIL, 
and, where applicable, store an appropriate DTC readable by a scan tool 
when a malfunction is present and the monitoring conditions have been 
satisfied for each individual monitor required by this section.
    (B) The evaluation must verify that the malfunction of any 
component used to enable another OBD monitor but that does not itself 
result in MIL activation (e.g., fuel level sensor) will not inhibit the 
ability of other OBD monitors to detect malfunctions properly.
    (C) The evaluation must verify that the software used to track the 
numerator and denominator for the purpose of determining in-use 
monitoring frequency increments as required by paragraph (d)(2) of this 
section.
    (D) Malfunctions may be implanted mechanically or simulated 
electronically, but internal onboard computer hardware or software 
changes shall not be used to simulate malfunctions. For monitors that 
are required to indicate a malfunction before emissions exceed an 
emission threshold, manufacturers are not required to use 
malfunctioning components/systems set exactly at their malfunction 
criteria limits. Emission testing is not required to confirm that the 
malfunction is detected before the appropriate emission thresholds are 
exceeded.
    (E) The manufacturer must submit a proposed test plan for approval 
prior to performing evaluation testing. The test plan must identify the 
method used to induce a malfunction for each monitor.
    (F) If the demonstration of a specific monitor cannot be reasonably 
performed without causing physical damage to the test vehicle (e.g., 
onboard computer internal circuit malfunctions), the

[[Page 3312]]

manufacturer may omit the specific demonstration.
    (G) For evaluation of test vehicles selected in accordance with 
paragraph (j)(2)(ii) of this section, the manufacturer is not required 
to demonstrate monitors that were demonstrated prior to certification 
as required in paragraph (l) of this section.
    (iv) The manufacturer must submit a report of the results of all 
testing conducted as required by paragraph (j)(2) of this section. The 
report must identify the method used to induce a malfunction in each 
monitor, the MIL activation status, and the DTC(s) stored.
    (3) Verification of in-use monitoring performance ratios.
    (i) The manufacturer must collect and report in-use monitoring 
performance data representative of production vehicles (i.e., engine 
rating and chassis application combination). The manufacturer must 
collect and report the data to the Administrator within 12 months after 
the first production vehicle was first introduced into commerce.
    (ii) The manufacturer must separate production vehicles into the 
monitoring performance groups and submit data that represents each of 
these groups. The groups shall be based on the following criteria:
    (A) Emission control system architecture. All engines that use the 
same or similar emissions control system architecture (e.g., EGR with 
DPF and SCR; EGR with DPF and NOX adsorber; EGR with DPF-
only) and associated monitoring system would be in the same emission 
architecture category.
    (B) Vehicle application type. Within an emission architecture 
category, engines shall be separated into one of three vehicle 
application types: engines intended primarily for line-haul chassis 
applications, engines intended primarily for urban delivery chassis 
applications, and all other engines.
    (iii) The manufacturer may use an alternative grouping method to 
collect representative data. To do so, the manufacturer must show that 
the alternative groups include production vehicles using similar 
emission controls, OBD strategies, monitoring condition calibrations, 
and vehicle application driving/usage patterns such that they are 
expected to have similar in-use monitoring performance. The 
manufacturer will still be required to submit one set of data for each 
of the alternative groups.
    (iv) For each monitoring performance group, the data must include 
all of the in-use performance tracking data (i.e., all numerators, 
denominators, the general denominator, and the ignition cycle counter), 
the date the data were collected, the odometer reading, the VIN, and 
the calibration ID.
    (v) The manufacturer must submit a plan to the Administrator that 
details the types of production vehicles in each monitoring performance 
group, the number of vehicles per group to be sampled, the sampling 
method, the timeline to collect the data, and the reporting format. The 
plan must provide for effective collection of data from, at least, 15 
vehicles per monitoring performance group and provide for data that 
represent a broad range of temperature conditions. The plan shall not, 
by design, exclude or include specific vehicles in an attempt to 
collect data only from vehicles expected to have the highest in-use 
performance ratios.
    (vi) The 12 month deadline for reporting may be extended to 18 
months if the manufacturer can show that the delay is justified. In 
such a case, an interim report of progress to date must be submitted 
within the 12 month deadline.
    (k) Standardization requirements.
    (1) Reference materials. The OBD system must conform with the 
following Society of Automotive Engineers (SAE) standards and/or the 
following International Standards Organization (ISO) standards. The 
following documents are incorporated by reference, see Sec.  86.1:
    (i) SAE material. Copies of these materials may be obtained from 
the Society of Automotive Engineers, Inc., 400 Commonwealth Drive, 
Warrendale, PA 15096-0001.
    (A) SAE J1930 ``Electrical/Electronic Systems Diagnostic Terms, 
Definitions, Abbreviations, and Acronyms--Equivalent to ISO/TR 15031-
2:April 30, 2002,'' April 2002.
    (B) SAE J1939 ``Recommended Practice for a Serial Control and 
Communications Vehicle Network'' and the associated subparts included 
in SAE HS-1939, ``Truck and Bus Control and Communications Network 
Standards Manual,'' 2006 Edition.
    (C) [Reserved.]
    (D) SAE J1978 ``OBD II Scan Tool--Equivalent to ISO/DIS 15031-4: 
December 14, 2001,'' April 2002.
    (E) SAE J1979 ``E/E Diagnostic Test Modes--Equivalent to ISO/DIS 
15031-5:April 30, 2002,'' April 2002.
    (F) SAE J2012 ``Diagnostic Trouble Code Definitions--Equivalent to 
ISO/DIS 15031-6:April 30, 2002,'' April 2002.
    (G) SAE J2403 ``Medium/Heavy-Duty E/E Systems Diagnosis 
Nomenclature,'' August 2004.
    (H) SAE J2534 ``Recommended Practice for Pass-Thru Vehicle 
Reprogramming,'' February 2002.
    (ii) ISO materials. Copies of these materials may be obtained from 
the International Organization for Standardization, Case Postale 56, 
CH-1211 Geneva 20, Switzerland.
    (A) ISO 15765-4:2001 ``Road Vehicles-Diagnostics on Controller Area 
Network (CAN)--Part 4: Requirements for emission-related systems,'' 
December 2001.
    (2) The manufacturer defined data link connector must be accessible 
to a trained service technician.
    (3) [Reserved.]
    (4) Required emission related functions. The following functions 
must be implemented and must be accessible by, at a minimum, a 
manufacturer scan tool:
    (i) Ready status. The OBD system must indicate ``complete'' or 
``not complete'' for each of the installed monitored components and 
systems identified in paragraphs (g), (h) with the exception of (h)(4), 
and (i)(3) of this section. All components or systems identified in 
paragraphs (h)(1), (h)(2), or (i)(3) of this section that are monitored 
continuously must always indicate ``complete.'' Components or systems 
that are not subject to being monitored continuously must immediately 
indicate ``complete'' upon the respective monitor(s) being executed 
fully and determining that the component or system is not 
malfunctioning. A component or system must also indicate ``complete'' 
if, after the requisite number of decisions necessary for determining 
MIL status has been executed fully, the monitor indicates a malfunction 
of the component or system. The status for each of the monitored 
components or systems must indicate ``not complete'' whenever 
diagnostic memory has been cleared or erased by a means other than that 
allowed in paragraph (b) of this section. Normal vehicle shut down 
(i.e., key-off/engine-off) shall not cause the status to indicate ``not 
complete.''
    (A) The manufacturer may request that the ready status for a 
monitor be set to indicate ``complete'' without the monitor having 
completed if monitoring is disabled for a multiple number of drive 
cycles due to the continued presence of extreme operating conditions 
(e.g., cold ambient temperatures, high altitudes). Any such request 
must specify the conditions for monitoring system disablement and the 
number of drive cycles that would pass without monitor completion 
before ready status would be indicated as ``complete.''

[[Page 3313]]

    (B) For the evaporative system monitor, the ready status must be 
set in accordance with this paragraph (k)(4)(i) when both the 
functional check of the purge valve and, if applicable, the leak 
detection monitor of the hole size specified in paragraph (h)(7)(ii)(B) 
of this section indicate that they are complete.
    (C) If the manufacturer elects to indicate ready status through the 
MIL in the key-on/engine-off position as provided for in paragraph 
(b)(1)(iii) of this section, the ready status must be indicated in the 
following manner: If the ready status for all monitored components or 
systems is ``complete,'' the MIL shall remain continuously activated in 
the key-on/engine-off position for at least 10-20 seconds. If the ready 
status for one or more of the monitored components or systems is ``not 
complete,'' after at least 5 seconds of operation in the key-on/engine-
off position with the MIL activated continuously, the MIL shall blink 
once per second for 5-10 seconds. The data stream value for MIL status 
as required in paragraph (k)(4)(ii) of this section must indicate 
``commanded off'' during this sequence unless the MIL has also been 
``commanded on'' for a detected malfunction.
    (ii) Data stream. The following signals must be made available on 
demand through the data link connector. The actual signal value must 
always be used instead of a limp home value.
    (A) For gasoline engines.
    (1) Calculated load value, engine coolant temperature, engine 
speed, vehicle speed, and time elapsed since engine start.
    (2) Absolute load, fuel level (if used to enable or disable any 
other monitors), barometric pressure (directly measured or estimated), 
engine control module system voltage, and commanded equivalence ratio.
    (3) Number of stored MIL-on DTCs, catalyst temperature (if directly 
measured or estimated for purposes of enabling the catalyst 
monitor(s)), monitor status (i.e., disabled for the rest of this drive 
cycle, complete this drive cycle, or not complete this drive cycle) 
since last engine shut-off for each monitor used for ready status, 
distance traveled (or engine run time for engines not using vehicle 
speed information) while MIL activated, distance traveled (or engine 
run time for engines not using vehicle speed information) since DTC 
memory last erased, and number of warm-up cycles since DTC memory last 
erased, OBD requirements to which the engine is certified (e.g., 
California OBD, EPA OBD, European OBD, non-OBD) and MIL status (i.e., 
commanded-on or commanded-off).
    (B) For diesel engines.
    (1) Calculated load (engine torque as a percentage of maximum 
torque available at the current engine speed), driver's demand engine 
torque (as a percentage of maximum engine torque), actual engine torque 
(as a percentage of maximum engine torque), reference engine maximum 
torque, reference maximum engine torque as a function of engine speed 
(suspect parameter numbers (SPN) 539 through 543 defined by SAE J1939 
within parameter group number (PGN) 65251 for engine configuration), 
engine coolant temperature, engine oil temperature (if used for 
emission control or any OBD monitors), engine speed, and time elapsed 
since engine start.
    (2) Fuel level (if used to enable or disable any other monitors), 
vehicle speed (if used for emission control or any OBD monitors), 
barometric pressure (directly measured or estimated), and engine 
control module system voltage.
    (3) Number of stored MIL-on DTCs, monitor status (i.e., disabled 
for the rest of this drive cycle, complete this drive cycle, or not 
complete this drive cycle) since last engine shut-off for each monitor 
used for ready status, distance traveled (or engine run time for 
engines not using vehicle speed information) while MIL activated, 
distance traveled (or engine run time for engines not using vehicle 
speed information) since DTC memory last erased, number of warm-up 
cycles since DTC memory last erased, OBD requirements to which the 
engine is certified (e.g., California OBD, EPA OBD, European OBD, non-
OBD), and MIL status (i.e., commanded-on or commanded-off).
    (4) NOX NTE control area status (i.e., inside control 
area, outside control area, inside manufacturer-specific NOX 
NTE carve-out area, or deficiency active area) and PM NTE control area 
status (i.e., inside control area, outside control area, inside 
manufacturer-specific PM NTE carve-out area, or deficiency active 
area).
    (5) For purposes of the calculated load and torque parameters in 
paragraph (k)(4)(ii)(B)(1) of this section, manufacturers must report 
the most accurate values that are calculated within the applicable 
electronic control unit (e.g., the engine control module). Most 
accurate, in this context, must be of sufficient accuracy, resolution, 
and filtering to be used for the purposes of in-use emission testing 
with the engine still in a vehicle (e.g., using portable emission 
measurement equipment).
    (C) For all engines so equipped.
    (1) Absolute throttle position, relative throttle position, fuel 
control system status (e.g., open loop, closed loop), fuel trim, fuel 
pressure, ignition timing advance, fuel injection timing, intake air/
manifold temperature, engine intercooler temperature, manifold absolute 
pressure, air flow rate from mass air flow sensor, secondary air status 
(upstream, downstream, or atmosphere), ambient air temperature, 
commanded purge valve duty cycle/position, commanded EGR valve duty 
cycle/position, actual EGR valve duty cycle/position, EGR error between 
actual and commanded, PTO status (active or not active), redundant 
absolute throttle position (for electronic throttle or other systems 
that utilize two or more sensors), absolute pedal position, redundant 
absolute pedal position, commanded throttle motor position, fuel rate, 
boost pressure, commanded/target boost pressure, turbo inlet air 
temperature, fuel rail pressure, commanded fuel rail pressure, DPF 
inlet pressure, DPF inlet temperature, DPF outlet pressure, DPF outlet 
temperature, DPF delta pressure, exhaust pressure sensor output, 
exhaust gas temperature sensor output, injection control pressure, 
commanded injection control pressure, turbocharger/turbine speed, 
variable geometry turbo position, commanded variable geometry turbo 
position, turbocharger compressor inlet temperature, turbocharger 
compressor inlet pressure, turbocharger turbine inlet temperature, 
turbocharger turbine outlet temperature, waste gate valve position, and 
glow plug lamp status.
    (2) Oxygen sensor output, air/fuel ratio sensor output, 
NOX sensor output, and evaporative system vapor pressure.
    (iii) Freeze frame.
    (A) ``Freeze frame'' information required to be stored pursuant to 
paragraphs (b)(2)(iv), (h)(1)(iv)(D), and (h)(2)(vi) of this section 
must be made available on demand through the data link connector.
    (B) ``Freeze frame'' conditions must include the DTC that caused 
the data to be stored along with all of the signals required in 
paragraphs (k)(4)(ii)(A)(1) or (k)(4)(ii)(B)(1) of this section. Freeze 
frame conditions must also include all of the signals required on the 
engine in paragraphs (k)(4)(ii)(A)(2) and (k)(4)(ii)(B)(2) of this 
section, and paragraph (k)(4)(ii)(C)(1) of this section that are used 
for diagnostic or control purposes in the specific monitor or emission-
critical powertrain control unit that stored the DTC.
    (C) Only one frame of data is required to be recorded. The 
manufacturer may choose to store additional frames provided that at 
least the required frame

[[Page 3314]]

can be read by, at a minimum, a manufacturer scan tool.
    (iv) Diagnostic trouble codes.
    (A) For all monitored components and systems, any stored pending, 
MIL-on, and previous-MIL-on DTCs must be made available through the 
diagnostic connector.
    (B) The stored DTC must, to the extent possible, pinpoint the 
probable cause of the malfunction or potential malfunction. To the 
extent feasible, the manufacturer must use separate DTCs for every 
monitor where the monitor and repair procedure or probable cause of the 
malfunction is different. In general, rationality and functional checks 
must use different DTCs than the respective circuit integrity checks. 
Additionally, input component circuit integrity checks must use 
different DTCs for distinct malfunctions (e.g., out-of-range low, out-
of-range high, open circuit).
    (C) The manufacturer must use appropriate standard-defined DTCs 
whenever possible. With Administrator approval, the manufacturer may 
use manufacturer-defined DTCs in accordance with the applicable 
standard's specifications. To do so, the manufacturer must be able to 
show a lack of available standard-defined DTCs, uniqueness of the 
monitor or monitored component, expected future usage of the monitor or 
component, and estimated usefulness in providing additional diagnostic 
and repair information to service technicians. Manufacturer-defined 
DTCs must be used in a consistent manner (i.e., the same DTC shall not 
be used to represent two different failure modes) across a 
manufacturer's entire product line.
    (D) A pending or MIL-on DTC (as required in paragraphs (g) through 
(i) of this section) must be stored and available to, at a minimum, a 
manufacturer scan tool within 10 seconds after a monitor has determined 
that a malfunction or potential malfunction has occurred. A permanent 
DTC must be stored and available to, at a minimum, a manufacturer scan 
tool no later than the end of an ignition cycle in which the 
corresponding MIL-on DTC that caused MIL activation has been stored.
    (E) Pending DTCs for all components and systems (including those 
monitored continuously and non-continuously) must be made available 
through the diagnostic connector. A manufacturer using alternative 
statistical protocols for MIL activation as allowed in paragraph 
(b)(2)(iii) of this section must submit the details of their protocol 
for setting pending DTCs. The protocol must be, overall, equivalent to 
the requirements of this paragraph (k)(4)(iv)(E) and provide service 
technicians with a quick and accurate indication of a potential 
malfunction.
    (F) Permanent DTC for all components and systems must be made 
available through the diagnostic connector in a format that 
distinguishes permanent DTCs from pending DTCs, MIL-on DTCs, and 
previous-MIL-on DTCs. A MIL-on DTC must be stored as a permanent DTC no 
later than the end of the ignition cycle and subsequently at all times 
that the MIL-on DTC is commanding the MIL on. Permanent DTCs must be 
stored in non-volatile random access memory (NVRAM) and shall not be 
erasable by any scan tool command or by disconnecting power to the on-
board computer. Permanent DTCs must be erasable if the engine control 
module is reprogrammed and the ready status described in paragraph 
(k)(4)(i) of this section for all monitored components and systems are 
set to ``not complete.'' The OBD system must have the ability to store 
a minimum of four current MIL-on DTCs as permanent DTCs in NVRAM. If 
the number of MIL-on DTCs currently commanding activation of the MIL 
exceeds the maximum number of permanent DTCs that can be stored, the 
OBD system must store the earliest detected MIL-on DTC as permanent 
DTC. If additional MIL-on DTCs are stored when the maximum number of 
permanent DTCs is already stored in NVRAM, the OBD system shall not 
replace any existing permanent DTC with the additional MIL-on DTCs.
    (v) Test results.
    (A) Except as provided for in paragraph (k)(4)(v)(G) of this 
section, for all monitored components and systems identified in 
paragraphs (g) and (h) of this section, results of the most recent 
monitoring of the components and systems and the test limits 
established for monitoring the respective components and systems must 
be stored and available through the data link.
    (B) The test results must be reported such that properly 
functioning components and systems (e.g., ``passing'' systems) do not 
store test values outside of the established test limits. Test limits 
must include both minimum and maximum acceptable values and must be 
defined so that a test result equal to either test limit is a 
``passing'' value, not a ``failing'' value.
    (C) [Reserved.]
    (D) The test results must be stored until updated by a more recent 
valid test result or the DTC memory of the OBD system computer is 
cleared. Upon DTC memory being cleared, test results reported for 
monitors that have not yet completed with valid test results since the 
last time the fault memory was cleared must report values of zero for 
the test result and test limits.
    (E) All test results and test limits must always be reported and 
the test results must be stored until updated by a more recent valid 
test result or the DTC memory of the OBD system computer is cleared.
    (F) The OBD system must store and report unique test results for 
each separate monitor.
    (G) The requirements of this paragraph (k)(4)(v) do not apply to 
continuous fuel system monitoring, cold start emission reduction 
strategy monitoring, and continuous circuit monitoring.
    (vi) Software calibration identification (CAL ID). On all engines, 
a single software calibration identification number (CAL ID) for each 
monitor or emission critical control unit(s) must be made available 
through the data link connector. A unique CAL ID must be used for every 
emission-related calibration and/or software set having at least one 
bit of different data from any other emission-related calibration and/
or software set. Control units coded with multiple emission or 
diagnostic calibrations and/or software sets must indicate a unique CAL 
ID for each variant in a manner that enables an off-board device to 
determine which variant is being used by the vehicle. Control units 
that use a strategy that will result in MIL activation if the incorrect 
variant is used (e.g., control units that contain variants for manual 
and automatic transmissions but will activate the MIL if the selected 
variant does not match the type of transmission mated to the engine) 
are not required to use unique CAL IDs.
    (vii) Software calibration verification number (CVN).
    (A) All engines must use an algorithm to calculate a single 
calibration verification number (CVN) that verifies the on-board 
computer software integrity for each monitor or emission critical 
control unit that is electronically reprogrammable. The CVN must be 
made available through the data link connector. The CVN must indicate 
whether the emission-related software and/or calibration data are valid 
and applicable for the given vehicle and CAL ID.
    (B) The CVN algorithm used to calculate the CVN must be of 
sufficient complexity that the same CVN is difficult to achieve with 
modified calibration values.
    (C) The CVN must be calculated at least once per drive cycle and 
stored until the CVN is subsequently updated. Except for immediately 
after a

[[Page 3315]]

reprogramming event or a non-volatile memory clear or for the first 30 
seconds of engine operation after a volatile memory clear or battery 
disconnect, the stored value must be made available through the data 
link connector to, at a minimum, a manufacturer scan tool. The stored 
CVN value shall not be erased when DTC memory is erased or during 
normal vehicle shut down (i.e., key-off/engine-off).
    (D) [Reserved.]
    (viii) Vehicle identification number (VIN).
    (A) All vehicles must have the vehicle identification number (VIN) 
available through the data link connector to, at a minimum, a 
manufacturer scan tool. Only one electronic control unit per vehicle 
may report the VIN to a scan tool.
    (B) If the VIN is reprogrammable, all emission-related diagnostic 
information identified in paragraph (k)(4)(ix)(A) of this section must 
be erased in conjunction with reprogramming of the VIN.
    (ix) Erasure of diagnostic information.
    (A) For purposes of this paragraph (k)(4)(ix), ``emission-related 
diagnostic information'' includes all of the following: ready status as 
required by paragraph (k)(4)(i) of this section; data stream 
information as required by paragraph (k)(4)(ii) of this section 
including the number of stored MIL-on DTCs, distance traveled while MIL 
activated, number of warm-up cycles since DTC memory last erased, and 
distance traveled since DTC memory last erased; freeze frame 
information as required by paragraph (k)(4)(iii) of this section; 
pending, MIL-on, and previous-MIL-on DTCs as required by paragraph 
(k)(4)(iv) of this section; and, test results as required by paragraph 
(k)(4)(v) of this section.
    (B) For all engines, the emission-related diagnostic information 
must be erased if commanded by any scan tool and may be erased if the 
power to the on-board computer is disconnected. If any of the emission-
related diagnostic information is commanded to be erased by any scan 
tool, all emission-related diagnostic information must be erased from 
all diagnostic or emission critical control units. The OBD system shall 
not allow a scan tool to erase a subset of the emission-related 
diagnostic information (e.g., the OBD system shall not allow a scan 
tool to erase only one of three stored DTCs or only information from 
one control unit without erasing information from the other control 
unit(s)).
    (5) In-use performance ratio tracking requirements.
    (i) For each monitor required in paragraphs (g) through (i) of this 
section to separately report an in-use performance ratio, manufacturers 
must implement software algorithms to report a numerator and 
denominator.
    (ii) For the numerator, denominator, general denominator, and 
ignition cycle counters required by paragraph (e) of this section, the 
following numerical value specifications apply:
    (A) Each number shall have a minimum value of zero and a maximum 
value of 65,535 with a resolution of one.
    (B) Each number shall be reset to zero only when a non-volatile 
random access memory (NVRAM) reset occurs (e.g., reprogramming event) 
or, if the numbers are stored in keep-alive memory (KAM), when KAM is 
lost due to an interruption in electrical power to the control unit 
(e.g., battery disconnect). Numbers shall not be reset to zero under 
any other circumstances including when a scan tool command to clear 
DTCs or reset KAM is received.
    (C) To avoid overflow problems, if either the numerator or 
denominator for a specific component reaches the maximum value of 
65,535 2, both numbers shall be divided by two before 
either is incremented again.
    (D) To avoid overflow problems, if the ignition cycle counter 
reaches the maximum value of 65,535 2, the ignition cycle 
counter shall roll over and increment to zero on the next ignition 
cycle.
    (E) To avoid overflow problems, if the general denominator reaches 
the maximum value of 65,535 2, the general denominator 
shall roll over and increment to zero on the next drive cycle that 
meets the general denominator definition.
    (F) If a vehicle is not equipped with a component (e.g., oxygen 
sensor bank 2, secondary air system), the corresponding numerator and 
denominator for that specific component shall always be reported as 
zero.
    (iii) For the ratio required by paragraph (e) of this section, the 
following numerical value specifications apply:
    (A) The ratio shall have a minimum value of zero and a maximum 
value of 7.99527 with a resolution of 0.000122.
    (B) The ratio for a specific component shall be considered to be 
zero whenever the corresponding numerator is equal to zero and the 
corresponding denominator is not zero.
    (C) The ratio for a specific component shall be considered to be 
the maximum value of 7.99527 if the corresponding denominator is zero 
or if the actual value of the numerator divided by the denominator 
exceeds the maximum value of 7.99527.
    (6) Engine run time tracking requirements.
    (i) For all gasoline and diesel engines, the manufacturer must 
implement software algorithms to track and report individually the 
amount of time the engine has been operated in the following 
conditions:
    (A) Total engine run time.
    (B) Total idle run time (with ``idle'' defined as accelerator pedal 
released by the driver, vehicle speed less than or equal to one mile 
per hour, engine speed greater than or equal to 50 to 150 rpm below the 
normal, warmed-up idle speed (as determined in the drive position for 
vehicles equipped with an automatic transmission), and power take-off 
not active).
    (C) Total run time with power take off active.
    (ii) For each counter specified in paragraph (k)(6)(i) of this 
section, the following numerical value specifications apply:
    (A) Each number shall be a four-byte value with a minimum value of 
zero, a resolution of one second per bit, and an accuracy of  ten seconds per drive cycle.
    (B) Each number shall be reset to zero only when a non-volatile 
memory reset occurs (e.g., reprogramming event). Numbers shall not be 
reset to zero under any other circumstances including when a scan tool 
(generic or enhanced) command to clear fault codes or reset KAM is 
received.
    (C) To avoid overflow problems, if any of the individual counters 
reach the maximum value, all counters shall be divided by two before 
any are incremented again.
    (D) The counters shall be made available to, at a minimum, a 
manufacturer scan tool and may be rescaled when transmitted from a 
resolution of one second per bit to no more than three minutes per bit.
    (l) Monitoring system demonstration requirements for certification.
    (1) General.
    (i) The manufacturer must submit emissions test data from one or 
more durability demonstration test engines (test engines).
    (ii) The Administrator may approve other demonstration protocols if 
the manufacturer can provide comparable assurance that the malfunction 
criteria are chosen based on meeting the malfunction criteria 
requirements and that the timeliness of malfunction detection is within 
the constraints of the applicable monitoring requirements.
    (iii) For flexible fuel engines capable of operating on more than 
one fuel or

[[Page 3316]]

fuel combinations, the manufacturer must submit a plan for providing 
emission test data. The plan must demonstrate that testing will 
represent properly the expected in-use fuel or fuel combinations.
    (2) Selection of test engines.
    (i) Prior to submitting any applications for certification for a 
model year, the manufacturer must notify the Administrator regarding 
the planned engine families and engine ratings within each family for 
that model year. The Administrator will select the engine family(ies) 
and the specific engine rating within the engine family(ies) that the 
manufacturer shall use as demonstration test engines. The selection of 
test vehicles for production evaluation testing as specified in 
paragraph (j)(2) of this section may take place during this selection 
process.
    (ii) The manufacturer must provide emissions test data from the OBD 
parent rating as defined in paragraph (o)(1) of this section.
    (iii) For the test engine, the manufacturer must use an engine aged 
for a minimum of 125 hours fitted with exhaust aftertreatment emission 
controls aged to be representative of useful life aging. The 
manufacturer is required to submit a description of the accelerated 
aging process and/or supporting data. The process and/or data must 
demonstrate assurance that deterioration of the exhaust aftertreatment 
emission controls is stabilized sufficiently such that it represents 
emission control performance at the end of the useful life.
    (3) Required testing. Except as otherwise described in this 
paragraph (l)(3), the manufacturer must perform single malfunction 
testing based on the applicable test with the components/systems set at 
their malfunction criteria limits as determined by the manufacturer for 
meeting the emissions thresholds required in paragraphs (g), (h), and 
(i) of this section.
    (i) Required testing for diesel-fueled/compression ignition 
engines.
    (A) Fuel system. The manufacturer must perform a separate test for 
each malfunction limit established by the manufacturer for the fuel 
system parameters (e.g., fuel pressure, injection timing) specified in 
paragraphs (g)(1)(ii)(A) through (g)(1)(ii)(C) of this section. When 
performing a test for a specific parameter, the fuel system must be 
operating at the malfunction criteria limit for the applicable 
parameter only. All other parameters must be operating with normal 
characteristics. In conducting the fuel system demonstration tests, the 
manufacturer may use computer modifications to cause the fuel system to 
operate at the malfunction limit if the manufacturer can demonstrate 
that the computer modifications produce test results equivalent to an 
induced hardware malfunction.
    (B) [Reserved.]
    (C) EGR system. The manufacturer must perform a separate test for 
each malfunction limit established by the manufacturer for the EGR 
system parameters (e.g., low flow, high flow, slow response) specified 
in paragraphs (g)(3)(ii)(A) through (g)(3)(ii)(C) of this section and 
in (g)(3)(ii)(E) of this section. In conducting the EGR system slow 
response demonstration tests, the manufacturer may use computer 
modifications to cause the EGR system to operate at the malfunction 
limit if the manufacturer can demonstrate that the computer 
modifications produce test results equivalent to an induced hardware 
malfunction.
    (D) Turbo boost control system. The manufacturer must perform a 
separate test for each malfunction limit established by the 
manufacturer for the turbo boost control system parameters (e.g., 
underboost, overboost, response) specified in paragraphs (g)(4)(ii)(A) 
through (g)(4)(ii)(C) of this section and in (g)(4)(ii)(E) of this 
section.
    (E) NMHC catalyst. The manufacturer must perform a separate test 
for each monitored NMHC catalyst(s). The catalyst(s) being evaluated 
must be deteriorated to the applicable malfunction limit established by 
the manufacturer for the monitoring required by paragraph (g)(5)(ii)(A) 
of this section and using methods established by the manufacturer in 
accordance with paragraph (l)(7) of this section. For each monitored 
NMHC catalyst(s), the manufacturer must also demonstrate that the OBD 
system will detect a catalyst malfunction with the catalyst at its 
maximum level of deterioration (i.e., the substrate(s) completely 
removed from the catalyst container or ``empty'' can). Emissions data 
are not required for the empty can demonstration.
    (F) NOX catalyst. The manufacturer must perform a 
separate test for each monitored NOX catalyst(s) (e.g., SCR 
catalyst). The catalyst(s) being evaluated must be deteriorated to the 
applicable malfunction criteria established by the manufacturer for the 
monitoring required by paragraphs (g)(6)(ii)(A) and (g)(6)(ii)(B) of 
this section and using methods established by the manufacturer in 
accordance with paragraph (l)(7) of this section. For each monitored 
NOX catalyst(s), the manufacturer must also demonstrate that 
the OBD system will detect a catalyst malfunction with the catalyst at 
its maximum level of deterioration (i.e., the substrate(s) completely 
removed from the catalyst container or ``empty'' can). Emissions data 
are not required for the empty can demonstration.
    (G) NOX adsorber. The manufacturer must perform a test 
using a NOX adsorber(s) deteriorated to the applicable 
malfunction limit established by the manufacturer for the monitoring 
required by paragraph (g)(7)(ii)(A) of this section. The manufacturer 
must also demonstrate that the OBD system will detect a NOX 
adsorber malfunction with the NOX adsorber at its maximum 
level of deterioration (i.e., the substrate(s) completely removed from 
the container or ``empty'' can). Emissions data are not required for 
the empty can demonstration.
    (H) Diesel particulate filter. The manufacturer must perform a 
separate test using a DPF deteriorated to the applicable malfunction 
limits established by the manufacturer for the monitoring required by 
paragraphs (g)(8)(ii)(A), (g)(8)(ii)(B), and (g)(8)(ii)(D) of this 
section. The manufacturer must also demonstrate that the OBD system 
will detect a DPF malfunction with the DPF at its maximum level of 
deterioration (i.e., the filter(s) completely removed from the filter 
container or ``empty'' can). Emissions data are not required for the 
empty can demonstration.
    (I) Exhaust gas sensor. The manufacturer must perform a separate 
test for each malfunction limit established by the manufacturer for the 
monitoring required in paragraphs (g)(9)(ii)(A), (g)(9)(iii)(A), and 
(g)(9)(iv)(A) of this section. When performing a test, all exhaust gas 
sensors used for the same purpose (e.g., for the same feedback control 
loop, for the same control feature on parallel exhaust banks) must be 
operating at the malfunction criteria limit for the applicable 
parameter only. All other exhaust gas sensor parameters must be 
operating with normal characteristics.
    (J) VVT system. The manufacturer must perform a separate test for 
each malfunction limit established by the manufacturer for the 
monitoring required in paragraphs (g)(10)(ii)(A) and (g)(10)(ii)(B) of 
this section. In conducting the VVT system demonstration tests, the 
manufacturer may use computer modifications to cause the VVT system to 
operate at the malfunction limit if the manufacturer can demonstrate 
that the computer modifications produce test results equivalent to an 
induced hardware malfunction.

[[Page 3317]]

    (K) For each of the testing requirements of this paragraph 
(l)(3)(i), if the manufacturer has established that only a functional 
check is required because no failure or deterioration of the specific 
tested system could result in an engine's emissions exceeding the 
applicable emissions thresholds, the manufacturer is not required to 
perform a demonstration test; however, the manufacturer is required to 
provide the data and/or engineering analysis used to determine that 
only a functional test of the system(s) is required.
    (ii) Required testing for gasoline-fueled/spark-ignition engines.
    (A) Fuel system. For engines with adaptive feedback based on the 
primary fuel control sensor(s), the manufacturer must perform a test 
with the adaptive feedback based on the primary fuel control sensor(s) 
at the rich limit(s) and a test at the lean limit(s) established by the 
manufacturer as required by paragraph (h)(1)(ii)(A) of this section to 
detect a malfunction before emissions exceed applicable emissions 
thresholds. For engines with feedback based on a secondary fuel control 
sensor(s) and subject to the malfunction criteria in paragraph 
(h)(1)(ii)(A) of this section, the manufacturer must perform a test 
with the feedback based on the secondary fuel control sensor(s) at the 
rich limit(s) and a test at the lean limit(s) established by the 
manufacturer as required by paragraph (h)(1)(ii)(A) of this section to 
detect a malfunction before emissions exceed the applicable emissions 
thresholds. For other fuel metering or control systems, the 
manufacturer must perform a test at the criteria limit(s). For purposes 
of fuel system testing as required by this paragraph (l)(3)(ii)(A), the 
malfunction(s) induced may result in a uniform distribution of fuel and 
air among the cylinders. Non uniform distribution of fuel and air used 
to induce a malfunction shall not cause misfire. In conducting the fuel 
system demonstration tests, the manufacturer may use computer 
modifications to cause the fuel system to operate at the malfunction 
limit. To do so, the manufacturer must be able to demonstrate that the 
computer modifications produce test results equivalent to an induced 
hardware malfunction.
    (B) Misfire. The manufacturer must perform a test at the 
malfunction criteria limit specified in paragraph (h)(2)(ii)(B) of this 
section.
    (C) EGR system. The manufacturer must perform a test at each flow 
limit calibrated to the malfunction criteria specified in paragraphs 
(h)(3)(ii)(A) and (h)(3)(ii)(B) of this section.
    (D) Cold start emission reduction strategy. The manufacturer must 
perform a test at the malfunction criteria for each component monitored 
according to paragraph (h)(4)(ii)(A) of this section.
    (E) Secondary air system. The manufacturer must perform a test at 
each flow limit calibrated to the malfunction criteria specified in 
paragraphs (h)(5)(ii)(A) and (h)(5)(ii)(B) of this section.
    (F) Catalyst. The manufacturer must perform a test using a catalyst 
system deteriorated to the malfunction criteria specified in paragraph 
(h)(6)(ii) of this section using methods established by the 
manufacturer in accordance with paragraph (l)(7)(ii) of this section. 
The manufacturer must also demonstrate that the OBD system will detect 
a catalyst system malfunction with the catalyst system at its maximum 
level of deterioration (i.e., the substrate(s) completely removed from 
the catalyst container or ``empty'' can). Emission data are not 
required for the empty can demonstration.
    (G) Exhaust gas sensor. The manufacturer must perform a test with 
all primary exhaust gas sensors used for fuel control simultaneously 
possessing a response rate deteriorated to the malfunction criteria 
limit specified in paragraph (h)(8)(ii)(A) of this section. The 
manufacturer must also perform a test for any other primary or 
secondary exhaust gas sensor parameter under parargraphs (h)(8)(ii)(A) 
and (h)(8)(iii)(A) of this section that can cause engine emissions to 
exceed the applicable emissions thresholds (e.g., shift in air/fuel 
ratio at which oxygen sensor switches, decreased amplitude). When 
performing additional test(s), all primary and secondary (if 
applicable) exhaust gas sensors used for emission control must be 
operating at the malfunction criteria limit for the applicable 
parameter only. All other primary and secondary exhaust gas sensor 
parameters must be operating with normal characteristics.
    (H) VVT system. The manufacturer must perform a test at each target 
error limit and slow response limit calibrated to the malfunction 
criteria specified in (h)(9)(ii)(A) and (h)(9)(ii)(B) of this section. 
In conducting the VVT system demonstration tests, the manufacturer may 
use computer modifications to cause the VVT system to operate at the 
malfunction limit. To do so, the manufacturer must be able to 
demonstrate that the computer modifications produce test results 
equivalent to an induced hardware malfunction.
    (I) For each of the testing requirements of this paragraph 
(l)(3)(ii), if the manufacturer has established that only a functional 
check is required because no failure or deterioration of the specific 
tested system could cause an engine's emissions to exceed the 
applicable emissions thresholds, the manufacturer is not required to 
perform a demonstration test; however the manufacturer is required to 
provide the data and/or engineering analyses used to determine that 
only a functional test of the system(s) is required.
    (iii) Required testing for all engines.
    (A) Other emission control systems. The manufacturer must conduct 
demonstration tests for all other emission control components (e.g., 
hydrocarbon traps, adsorbers) designed and calibrated to a malfunction 
limit based on an emissions threshold based on the requirements of 
paragraph (i)(4) of this section.
    (B) For each of the testing requirements of paragraph 
(l)(3)(iii)(A) of this section, if the manufacturer has established 
that only a functional check is required because no failure or 
deterioration of the specific tested system could result in an engine's 
emissions exceeding the applicable emissions thresholds, the 
manufacturer is not required to perform a demonstration test; however, 
the manufacturer is required to provide the data and/or engineering 
analysis used to determine that only a functional test of the system(s) 
is required.
    (iv) The manufacturer may electronically simulate deteriorated 
components but shall not make any engine control unit modifications 
when performing demonstration tests unless approved by the 
Administrator. All equipment necessary to duplicate the demonstration 
test must be made available to the Administrator upon request.
    (4) Testing protocol.
    (i) Preconditioning. The manufacturer must use an applicable cycle 
for preconditioning test engines prior to conducting each of the 
emission tests required by paragraph (l)(3) of this section. The 
manufacturer may perform a single additional preconditioning cycle, 
identical to the initial one, after a 20 minute hot soak but must 
demonstrate that such an additional cycle is necessary to stabilize the 
emissions control system. A practice of requiring a cold soak prior to 
conducting preconditioning cycles is not permitted.
    (ii) Test sequence.
    (A) The manufacturer must set individually each system or component 
on the test engine at the malfunction

[[Page 3318]]

criteria limit prior to conducting the applicable preconditioning 
cycle(s). If a second preconditioning cycle is permitted in accordance 
with paragraph (l)(4)(i) of this section, the manufacturer may adjust 
the system or component to be tested before conducting the second 
preconditioning cycle. The manufacturer shall not replace, modify, or 
adjust the system or component after the last preconditioning cycle has 
been completed.
    (B) After preconditioning, the test engine must be operated over 
the applicable cycle to allow for the initial detection of the tested 
system or component malfunction. This test cycle may be omitted from 
the testing protocol if it is unnecessary. If required by the 
monitoring strategy being tested, a cold soak may be performed prior to 
conducting this test cycle.
    (C) The test engine must then be operated over the applicable 
exhaust emissions test.
    (iii) [Reserved.]
    (iv) The manufacturer may request approval to use an alternative 
testing protocol for demonstration of MIL activation if the engine 
dynamometer emission test cycle does not allow all of a given monitor's 
enable conditions to be satisfied. The manufacturer may request the use 
of an alternative engine dynamometer test cycle or the use of chassis 
testing to demonstrate proper MIL activation. To do so, the 
manufacturer must demonstrate the technical necessity for using an 
alternative test cycle and the degree to which the alternative test 
cycle demonstrates that in-use operation with the malfunctioning 
component will result in proper MIL activation.
    (5) Evaluation protocol. Full OBD engine ratings, as defined by 
paragraph (o)(1) of this section, shall be evaluated according to the 
following protocol:
    (i) For all tests conducted as required by paragraph (l) of this 
section, the MIL must activate before the end of the first engine start 
portion of the applicable test.
    (ii) If the MIL activates prior to emissions exceeding the 
applicable malfunction criteria limits specified in paragraphs (g) 
through (i) of this section, no further demonstration is required. With 
respect to the misfire monitor demonstration test, if the manufacturer 
has elected to use the minimum misfire malfunction criteria of one 
percent as allowed in paragraph (h)(2)(ii)(B) of this section, no 
further demonstration is required provided the MIL activates with 
engine misfire occurring at the malfunction criteria limit.
    (iii) If the MIL does not activate when the system or component is 
set at its malfunction criteria limit(s), the criteria limit(s) or the 
OBD system is not acceptable.
    (A) Except for testing of the catalyst or DPF system, if the MIL 
first activates after emissions exceed the applicable malfunction 
criteria specified in paragraphs (g) through (i) of this section, the 
test engine shall be retested with the tested system or component 
adjusted so that the MIL will activate before emissions exceed the 
applicable malfunction criteria specified in paragraphs (g) through (i) 
of this section. If the component cannot be so adjusted because an 
alternative fuel or emission control strategy is used when a 
malfunction is detected (e.g., open loop fuel control used after an 
oxygen sensor malfunction is detected), the test engine shall be 
retested with the component adjusted to the worst acceptable limit 
(i.e., the applicable OBD monitor indicates that the component is 
performing at or slightly better than the malfunction criteria limit). 
When tested with the component so adjusted, the MIL must not activate 
during the test and the engine emissions must be below the applicable 
malfunction criteria specified in paragraphs (g) through (i) of this 
section.
    (B) In testing the catalyst or DPF system, if the MIL first 
activates after emissions exceed the applicable emissions threshold(s) 
specified in paragraphs (g) and (h) of this section, the tested engine 
shall be retested with a less deteriorated catalyst or DPF system 
(i.e., more of the applicable engine out pollutants are converted or 
trapped). For the OBD system to be approved, testing shall be continued 
until the MIL activates with emissions below the applicable thresholds 
of paragraphs (g) and (h) of this section, or the MIL activates with 
emissions within a range no more than 20 percent below the applicable 
emissions thresholds and 10 percent or less above those emissions 
thresholds.
    (iv) If an OBD system is determined to be unacceptable by the 
criteria of this paragraph (l)(5) of this section, the manufacturer may 
recalibrate and retest the system on the same test engine. In such a 
case, the manufacturer must confirm, by retesting, that all systems and 
components that were tested prior to the recalibration and are affected 
by it still function properly with the recalibrated OBD system.
    (6) Confirmatory testing.
    (i) The Administrator may perform confirmatory testing to verify 
the emission test data submitted by the manufacturer as required by 
this paragraph (l) of this section comply with its requirements and the 
malfunction criteria set forth in paragraphs (g) through (i) of this 
section. Such confirmatory testing is limited to the test engine 
required by paragraph (l)(2) of this section.
    (ii) To conduct this confirmatory testing, the Administrator may 
install appropriately deteriorated or malfunctioning components (or 
simulate them) in an otherwise properly functioning test engine of an 
engine rating represented by the demonstration test engine in order to 
test any of the components or systems required to be tested by 
paragraph (l) of this section. The manufacturer shall make available, 
if requested, an engine and all test equipment (e.g., malfunction 
simulators, deteriorated components) necessary to duplicate the 
manufacturer's testing. Such a request from the Administrator shall 
occur within six months of reviewing and approving the demonstration 
test engine data submitted by the manufacturer for the specific engine 
rating.
    (7) Catalyst aging.
    (i) Diesel catalysts. For purposes of determining the catalyst 
malfunction limits for the monitoring required by paragraphs 
(g)(5)(ii)(A), (g)(5)(ii)(B), and (g)(6)(ii)(A) of this section, where 
those catalysts are monitored individually, the manufacturer must use a 
catalyst deteriorated to the malfunction criteria using methods 
established by the manufacturer to represent real world catalyst 
deterioration under normal and malfunctioning engine operating 
conditions. For purposes of determining the catalyst malfunction limits 
for the monitoring required by paragraphs (g)(5)(ii)(A), (g)(5)(ii)(B), 
and (g)(6)(ii)(A) of this section, where those catalysts are monitored 
in combination with other catalysts, the manufacturer must submit their 
catalyst system aging and monitoring plan to the Administrator as part 
of their certification documentation package. The plan must include the 
description, emission control purpose, and location of each component, 
the monitoring strategy for each component and/or combination of 
components, and the method for determining the applicable malfunction 
criteria including the deterioration/aging process.
    (ii) Gasoline catalysts. For the purposes of determining the 
catalyst system malfunction criteria in paragraph (h)(6)(ii) of this 
section, the manufacturer must use a catalyst system deteriorated to 
the malfunction criteria using methods established by the manufacturer 
to represent real world catalyst deterioration under normal and 
malfunctioning operating conditions. The malfunction criteria must be

[[Page 3319]]

established by using a catalyst system with all monitored and 
unmonitored (downstream of the sensor utilized for catalyst monitoring) 
catalysts simultaneously deteriorated to the malfunction criteria 
except for those engines that use fuel shutoff to prevent over-fueling 
during engine misfire conditions. For such engines, the malfunction 
criteria must be established by using a catalyst system with all 
monitored catalysts simultaneously deteriorated to the malfunction 
criteria while unmonitored catalysts shall be deteriorated to the end 
of the engine's useful life.
    (m) Certification documentation requirements.
    (1) When submitting an application for certification of an engine, 
the manufacturer must submit the following documentation. If any of the 
items listed here are standardized for all of the manufacturer's 
engines, the manufacturer may, for each model year, submit one set of 
documents covering the standardized items for all of its engines.
    (i) For the required documentation that is not standardized across 
all engines, the manufacturer may be allowed to submit documentation 
for certification from one engine that is representative of other 
engines. All such engines shall be considered to be part of an OBD 
certification documentation group. To represent the OBD group, the 
chosen engine must be certified to the most stringent emissions 
standards and OBD monitoring requirements and cover all of the 
emissions control devices for the engines in the group and covered by 
the submitted documentation. Such OBD groups must be approved in 
advance of certification.
    (ii) Upon approval, one or more of the documentation requirements 
of this paragraph (m) of this section may be waived or modified if the 
information required is redundant or unnecessarily burdensome to 
generate.
    (iii) To the extent possible, the certification documentation must 
use SAE J1930 or J2403 terms, abbreviations, and acronyms.
    (2) Unless otherwise specified, the following information must be 
submitted as part of the certification application and prior to 
receiving a certificate.
    (i) A description of the functional operation of the OBD system 
including a complete written description for each monitoring strategy 
that outlines every step in the decision-making process of the monitor. 
Algorithms, diagrams, samples of data, and/or other graphical 
representations of the monitoring strategy shall be included where 
necessary to adequately describe the information.
    (ii) A table including the following information for each monitored 
component or system (either computer-sensed or computer-controlled) of 
the emissions control system:
    (A) Corresponding diagnostic trouble code.
    (B) Monitoring method or procedure for malfunction detection.
    (C) Primary malfunction detection parameter and its type of output 
signal.
    (D) Malfunction criteria limits used to evaluate output signal of 
primary parameter.
    (E) Other monitored secondary parameters and conditions (in 
engineering units) necessary for malfunction detection.
    (F) Monitoring time length and frequency of monitoring events.
    (G) Criteria for storing a diagnostic trouble code.
    (H) Criteria for activating a malfunction indicator light.
    (I) Criteria used for determining out-of-range values and input 
component rationality checks.
    (iii) Whenever possible, the table required by paragraph (m)(2)(ii) 
of this section shall use the following engineering units:
    (A) Degrees Celsius for all temperature criteria.
    (B) KiloPascals (KPa) for all pressure criteria related to manifold 
or atmospheric pressure.
    (C) Grams (g) for all intake air mass criteria.
    (D) Pascals (Pa) for all pressure criteria related to evaporative 
system vapor pressure.
    (E) Miles per hour (mph) for all vehicle speed criteria.
    (F) Relative percent (%) for all relative throttle position 
criteria (as defined in SAE J1979/J1939).
    (G) Voltage (V) for all absolute throttle position criteria (as 
defined in SAE J1979/J1939).
    (H) Per crankshaft revolution (/rev) for all changes per ignition 
event based criteria (e.g., g/rev instead of g/stroke or g/firing).
    (I) Per second (/sec) for all changes per time based criteria 
(e.g., g/sec).
    (J) Percent of nominal tank volume (%) for all fuel tank level 
criteria.
    (iv) A logic flowchart describing the step-by-step evaluation of 
the enable criteria and malfunction criteria for each monitored 
emission related component or system.
    (v) Emissions test data, a description of the testing sequence 
(e.g., the number and types of preconditioning cycles), approximate 
time (in seconds) of MIL activation during the test, diagnostic trouble 
code(s) and freeze frame information stored at the time of detection, 
corresponding test results (e.g. SAE J1979 Mode/Service $06, SAE J1939 
Diagnostic Message 8 (DM8)) stored during the test, and a description 
of the modified or deteriorated components used for malfunction 
simulation with respect to the demonstration tests specified in 
paragraph (l) of this section. The freeze frame data are not required 
for engines subject to paragraph (o)(2) of this section.
    (vi) For gasoline engines, data supporting the misfire monitor, 
including:
    (A) The established percentage of misfire that can be tolerated 
without damaging the catalyst over the full range of engine speed and 
load conditions.
    (B) Data demonstrating the probability of detection of misfire 
events by the misfire monitoring system over the full engine speed and 
load operating range for the following misfire patterns: random 
cylinders misfiring at the malfunction criteria established in 
paragraph (h)(2)(ii)(B) of this section, one cylinder continuously 
misfiring, and paired cylinders continuously misfiring.
    (C) Data identifying all disablement of misfire monitoring that 
occurs during the FTP. For every disablement that occurs during the 
cycles, the data shall identify: when the disablement occurred relative 
to the driver's trace, the number of engine revolutions during which 
each disablement was present, and which disable condition documented in 
the certification application caused the disablement.
    (D) Manufacturers are not required to use the durability 
demonstration engine to collect the misfire data required by paragraph 
(m)(2)(vi) of this section.
    (vii) Data supporting the limit for the time between engine 
starting and attaining the designated heating temperature for after-
start heated catalyst systems.
    (viii) Data supporting the criteria used to detect a malfunction of 
the fuel system, EGR system, boost pressure control system, catalyst, 
NOX adsorber, DPF, cold start emission reduction strategy, 
secondary air, evaporative system, VVT system, exhaust gas sensors, and 
other emission controls that causes emissions to exceed the applicable 
malfunction criteria specified in paragraphs (g) through (i) of this 
section. For diesel engine monitors required by paragraphs (g) and (i) 
of this section that are required to indicate a malfunction before 
emissions exceed an emission threshold based on any applicable standard 
(e.g., 2.5 times any

[[Page 3320]]

of the applicable standards), the test cycle and standard determined by 
the manufacturer to be the most stringent for each applicable monitor 
in accordance with paragraph (f)(1) of this section.
    (ix) A list of all electronic powertrain input and output signals 
(including those not monitored by the OBD system) that identifies which 
signals are monitored by the OBD system. For input and output signals 
that are monitored as comprehensive components, the listing shall also 
identify the specific diagnostic trouble code for each malfunction 
criteria (e.g., out-of-range low, out-of-range high, open circuit, 
rationality low, rationality high).
    (x) A written description of all parameters and conditions 
necessary to begin closed-loop/feedback control of emission control 
systems (e.g., fuel system, boost pressure, EGR flow, SCR reductant 
delivery, DPF regeneration, fuel system pressure).
    (xi) A written identification of the communication protocol 
utilized by each engine for communication with a scan tool.
    (xii) Reserved.
    (xiii) A written description of the method used by the manufacturer 
to meet the requirements of paragraph (i)(2) of this section (crankcase 
ventilation system monitoring) including diagrams or pictures of valve 
and/or hose connections.
    (xiv) Build specifications provided to engine purchasers or chassis 
manufacturers detailing all specifications or limitations imposed on 
the engine purchaser relevant to OBD requirements or emissions 
compliance (e.g., cooling system heat rejection rates). A description 
of the method or copies of agreements used to ensure engine purchasers 
or chassis manufacturers will comply with the OBD and emissions 
relevant build specifications (e.g., signed agreements, required audit/
evaluation procedures).
    (xv) Any other information determined by the Administrator to be 
necessary to demonstrate compliance with the requirements of this 
section.
    (n) Deficiencies.
    (1) Upon application by the manufacturer, the Administrator may 
accept an OBD system as compliant even though specific requirements are 
not fully met. Such compliances without meeting specific requirements, 
or deficiencies, will be granted only if compliance is infeasible or 
unreasonable considering such factors as, but not limited to: technical 
feasibility of the given monitor and lead time and production cycles 
including phase-in or phase-out of engines or vehicle designs and 
programmed upgrades of computers. Unmet requirements shall not be 
carried over from the previous model year except where unreasonable 
hardware or software modifications are necessary to correct the 
deficiency, and the manufacturer has demonstrated an acceptable level 
of effort toward compliance as determined by the Administrator. 
Furthermore, EPA will not accept any deficiency requests that include 
the complete lack of a major diagnostic monitor (``major'' diagnostic 
monitors being those for exhaust aftertreatment devices, oxygen sensor, 
air-fuel ratio sensor, NOX sensor, engine misfire, 
evaporative leaks, and diesel EGR, if equipped), with the possible 
exception of the special provisions for alternative fueled engines. For 
alternative fueled heavy-duty engines (e.g. natural gas, liquefied 
petroleum gas, methanol, ethanol), manufacturers may request the 
Administrator to waive specific monitoring requirements of this section 
for which monitoring may not be reliable with respect to the use of the 
alternative fuel. At a minimum, alternative fuel engines must be 
equipped with an OBD system meeting OBD requirements to the extent 
feasible as approved by the Administrator.
    (2) In the event the manufacturer seeks to carry-over a deficiency 
from a past model year to the current model year, the manufacturer must 
re-apply for approval to do so. In considering the request to carry-
over a deficiency, the Administrator shall consider the manufacturer's 
progress towards correcting the deficiency. The Administrator may not 
allow manufacturers to carry over monitoring system deficiencies for 
more than two model years unless it can be demonstrated that 
substantial engine hardware modifications and additional lead time 
beyond two years are necessary to correct the deficiency.
    (3) A deficiency shall not be granted retroactively (i.e., after 
the engine has been certified).
    (o) Implementation schedule. Except as provided for in paragraphs 
(o)(4) and (o)(5) of this section, the requirements of this section 
must be met according to the following provisions:
    (1) Full OBD. The manufacturer must implement an OBD system meeting 
the requirements of this section on one engine rating within one engine 
family of the manufacturer's product line. This ``full OBD'' rating 
will be known as the ``OBD parent'' rating. The OBD parent rating must 
be chosen as the rating having the highest weighted projected U.S. 
sales within the engine family having the highest weighted projected 
U.S. sales, with U.S. sales being weighted by the useful life of the 
engine rating.
    (2) Extrapolated OBD. For all other engine ratings within the 
engine family from which the OBD parent rating has been selected, the 
manufacturer must implement an OBD system meeting the requirements of 
this section except that the OBD system is not required to detect a 
malfunction prior to exceeding the emission thresholds shown in Table 1 
of paragraph (g) of this section and Table 2 of paragraph (h) of this 
section. These extrapolated OBD engines will be known as the ``OBD 
child'' ratings. On these OBD child ratings, rather than detecting a 
malfunction prior to exceeding the emission thresholds, the 
manufacturer must submit a plan for Administrator review and approval 
that details the engineering evaluation the manufacturer will use to 
establish the malfunction criteria for the OBD child ratings. The plan 
must demonstrate both the use of good engineering judgment in 
establishing the malfunction criteria, and robust detection of 
malfunctions, including consideration of differences of base engine, 
calibration, emission control components, and emission control 
strategies.
    (3) Engine families other than those from which the parent and 
child ratings have been selected are not subject to the requirements of 
this section.
    (4) Small volume manufacturers, as defined in Sec.  86.094-14(b)(1) 
and (2), are exempt from the requirements of Sec.  86.010-18.
    (5) Engines certified as alternative fueled engines are exempt from 
the requirements of Sec.  86.010-18.
    (p) In-use compliance standards. For monitors required to indicate 
a malfunction before emissions exceed a certain emission threshold 
(e.g., 2.5 times any of the applicable standards):
    (1) On the full OBD rating (i.e., the parent rating) as defined in 
paragraph (o)(1) of this section, separate in-use emissions thresholds 
shall apply. These thresholds are determined by doubling the applicable 
thresholds as shown in Table 1 of paragraph (g) and Table 2 of 
paragraph (h) of this section. The resultant thresholds apply only in-
use and do not apply for certification or selective enforcement 
auditing.
    (2) The extrapolated OBD ratings (i.e., the child ratings) as 
defined in paragraph (o)(2) of this section shall not be evaluated 
against emissions levels for purposes of OBD compliance in-use.
    (3) Only the test cycle and standard determined and identified by 
the manufacturer at the time of certification in accordance with 
paragraph (f) of this section as the most stringent shall be

[[Page 3321]]

used for the purpose of determining OBD system noncompliance in-use.
    (4) An OBD system shall not be considered noncompliant solely due 
to a failure or deterioration mode of a monitored component or system 
that could not have been reasonably foreseen to occur by the 
manufacturer.
    8. Section 86.010-30 is added to Subpart A to read as follows:


Sec.  86.010-30  Certification.

    Section 86.010-30 includes text that specifies requirements that 
differ from Sec. Sec.  86.094-30, 86.095-30, 86.096-30, 86.098-30, 
86.001-30, 86.004-30 or 86.007-30. Where a paragraph in Sec.  86.094-
30, Sec.  86.095-30, Sec.  86.096-30, Sec.  86.098-30, Sec.  86.001-30, 
Sec.  86.004-30 or Sec.  86.007-30 is identical and applicable to Sec.  
86.010-30, this may be indicated by specifying the corresponding 
paragraph and the statement ``[Reserved]. For guidance see Sec.  
86.094-30.'' or ``[Reserved]. For guidance see Sec.  86.095-30.'' or 
``[Reserved]. For guidance see Sec.  86.096-30.'' or ``[Reserved]. For 
guidance see Sec.  86.098-30.'' or ``[Reserved]. For guidance see Sec.  
86.001-30.'' or ``[Reserved]. For guidance see Sec.  86.004-30.'' or 
``[Reserved]. For guidance see Sec.  86.007-30.''
    (a)(1) and (a)(2) [Reserved]. For guidance see Sec.  86.094-30.
    (a)(3)(i) through (a)(4)(ii) [Reserved]. For guidance see Sec.  
86.004-30.
    (a)(4)(iii) introductory text through (a)(4)(iii)(C) [Reserved]. 
For guidance see Sec.  86.094-30.
    (a)(4)(iv) introductory text [Reserved]. For guidance see Sec.  
86.095-30.
    (a)(4)(iv)(A)-(a)(9) [Reserved]. For guidance see Sec.  86.094-30.
    (a)(10) and (a)(11) [Reserved]. For guidance see Sec.  86.004-30.
    (a)(12) [Reserved]. For guidance see Sec.  86.094-30.
    (a)(13) [Reserved]. For guidance see Sec.  86.095-30.
    (a)(14) [Reserved]. For guidance see Sec.  86.094-30.
    (a)(15)-(18) [Reserved]. For guidance see Sec.  86.096-30.
    (a)(19) [Reserved]. For guidance see Sec.  86.098-30.
    (a)(20) [Reserved]. For guidance see Sec.  86.001-30.
    (a)(21) [Reserved]. For guidance see Sec.  86.004-30.
    (b)(1) introductory text through (b)(1)(ii)(A) [Reserved]. For 
guidance see Sec.  86.094-30.
    (b)(1)(ii)(B) [Reserved]. For guidance see Sec.  86.004-30.
    (b)(1)(ii)(C) [Reserved]. For guidance see Sec.  86.094-30.
    (b)(1)(ii)(D) [Reserved]. For guidance see Sec.  86.004-30.
    (b)(1)(iii) and (b)(1)(iv) [Reserved]. For guidance see Sec.  
86.094-30.
    (b)(2) [Reserved]. For guidance see Sec.  86.098-30.
    (b)(3)-(b)(4)(i) [Reserved]. For guidance see Sec.  86.094-30.
    (b)(4)(ii) introductory text [Reserved]. For guidance see Sec.  
86.098-30.
    (b)(4)(ii)(A) [Reserved]. For guidance see Sec.  86.094-30.
    (b)(4)(ii)(B)-(b)(4)(iv) [Reserved]. For guidance see Sec.  86.098-
30.
    (b)(5)-(e) [Reserved]. For guidance see Sec.  86.094-30.
    (f) For engine families required to have an OBD system and meant 
for applications less than or equal to 14,000 pounds GVWR, 
certification will not be granted if, for any test vehicle approved by 
the Administrator in consultation with the manufacturer, the 
malfunction indicator light does not activate under any of the 
following circumstances, unless the manufacturer can demonstrate that 
any identified OBD problems discovered during the Administrator's 
evaluation will be corrected on production vehicles.
    (f)(1)(i) Otto-cycle. [Reserved]. For guidance see Sec.  86.004-30.
    (f)(1)(ii) Diesel.
    (A) If monitored for emissions performance--a reduction catalyst is 
replaced with a deteriorated or defective catalyst, or an electronic 
simulation of such, resulting in exhaust NOX emissions 
exceeding the applicable NOX FEL+0.3 g/bhp-hr. Also if 
monitored for emissions performance--an oxidation catalyst is replaced 
with a deteriorated or defective catalyst, or an electronic simulation 
of such, resulting in exhaust NMHC emissions exceeding 2.5 times the 
applicable NMHC standard.
    (B) If monitored for performance--a particulate trap is replaced 
with a deteriorated or defective trap, or an electronic simulation of 
such, resulting in either exhaust PM emissions exceeding the applicable 
FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is higher; or, exhaust 
NMHC emissions exceeding 2.5 times the applicable NMHC standard. Also, 
if monitored for performance--a particulate trap is replaced with a 
catastrophically failed trap or a simulation of such.
    (f)(2) [Reserved]. For guidance see Sec.  86.004-30.
    (f)(3)(i) Oxygen sensors and air-fuel ratio sensors downstream of 
aftertreatment devices.
    (f)(3)(i)(A) [Reserved]. For guidance see Sec.  86.007-30.
    (f)(3)(i)(B) Diesel. If so equipped, any oxygen sensor or air-fuel 
ratio sensor located downstream of aftertreatment devices is replaced 
with a deteriorated or defective sensor, or an electronic simulation of 
such, resulting in exhaust emissions exceeding any of the following 
levels: the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, 
whichever is higher; or, the applicable NOX FEL+0.3 g/bhp-
hr; or, 2.5 times the applicable NMHC standard.
    (ii) Oxygen sensors and air-fuel ratio sensors upstream of 
aftertreatment devices.
    (f)(3)(ii)(A) [Reserved]. For guidance see Sec.  86.007-30.
    (f)(3)(ii)(B) Diesel. If so equipped, any oxygen sensor or air-fuel 
ratio sensor located upstream of aftertreatment devices is replaced 
with a deteriorated or defective sensor, or an electronic simulation of 
such, resulting in exhaust emissions exceeding any of the following 
levels: the applicable PM FEL+0.02 g/bhp-hr or 0.03 g/bhp-hr PM, 
whichever is higher; or, the applicable NOX FEL+0.3 g/bhp-
hr; or, 2.5 times the applicable NMHC standard; or, 2.5 times the 
applicable CO standard.
    (iii) NOX sensors.
    (f)(3)(iii)(A) [Reserved]. For guidance see Sec.  86.007-30.
    (f)(3)(iii)(B) Diesel. If so equipped, any NOX sensor is 
replaced with a deteriorated or defective sensor, or an electronic 
simulation of such, resulting in exhaust emissions exceeding any of the 
following levels: the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr 
PM, whichever is higher; or, the applicable NOX FEL+0.3 g/
bhp-hr.
    (f)(4) [Reserved]. For guidance see Sec.  86.004-30.
    (f)(5)(i) [Reserved]. For guidance see Sec.  86.007-30.
    (f)(5)(ii) Diesel. A malfunction condition is induced in any 
emission-related engine system or component, including but not 
necessarily limited to, the exhaust gas recirculation (EGR) system, if 
equipped, and the fuel control system, singularly resulting in exhaust 
emissions exceeding any of the following levels: the applicable PM 
FEL+0.02 g/bhp-hr or 0.03 g/bhp-hr PM, whichever is higher; or, the 
applicable NOX FEL+0.3 g/bhp-hr; or, 2.5 times the 
applicable NMHC standard; or, 2.5 times the applicable CO standard.
    (f)(6) [Reserved]. For guidance see Sec.  86.004-30.
    9. Section 86.010-38 is added to subpart A to read as follows:


Sec.  86.010-38  Maintenance instructions.

    This Section 86.010-38 includes text that specifies requirements 
that differ from those specified in Sec.  86.007-38. Where a paragraph 
in Sec.  86.096-38, or Sec.  86.004-38, or Sec.  86.007-38 is identical 
and applicable to Sec.  86.010-38, this may be indicated by specifying 
the corresponding paragraph and the statement ``[Reserved]. For 
guidance see Sec.  86.096-38,'' ``[Reserved]. For guidance

[[Page 3322]]

see or Sec.  86.004-38, '' or ``[Reserved]. For guidance see Sec.  
86.007-38.''
    (a)-(f) [Reserved]. For guidance see Sec.  86.004-38.
    (g) [Reserved]. For guidance see Sec.  86.096-38. For incorporation 
by reference see Sec. Sec.  86.1 and 86.096-38.
    (h) [Reserved]. For guidance see Sec.  86.004-38.
    (i) [Reserved]. For guidance see Sec.  86.007-38.
    (j) Emission control diagnostic service information for heavy-duty 
engines used in vehicles over 14,000 pounds gross vehicle weight (GVW)
    (1) Manufacturers of heavy-duty engines used in applications 
weighing more than 14,000 pounds gross vehicle weight (GVW) that are 
subject to the applicable OBD requirements of this subpart A are 
subject to the provisions of this paragraph (j) beginning in the 2010 
model year. The provisions of this paragraph (j) apply only to those 
heavy-duty engines subject to the applicable OBD requirements.
    (2) Upon Administrator approval, manufacturers may alternatively 
comply with all service information and tool provisions found in Sec.  
86.096-38 that are applicable to 1996 and subsequent vehicles weighing 
less than 14,000 pounds gross vehicle weight (GVW).
    (3) General Requirements
    (i) Manufacturers shall furnish or cause to be furnished to any 
person engaged in the repairing or servicing of heavy-duty engines, or 
the Administrator upon request, any and all information needed to make 
use of the on-board diagnostic system and such other information, 
including instructions for making emission-related diagnosis and 
repairs, including but not limited to service manuals, technical 
service bulletins, recall service information, bi-directional control 
information, and training information, unless such information is 
protected by section 208(c) as a trade secret. No such information may 
be withheld under section 208(c) of the Act if that information is 
provided (directly or indirectly) by the manufacturer to franchised 
dealers or other persons engaged in the repair, diagnosing, or 
servicing of heavy-duty engines.
    (ii) Definitions. The following definitions apply for this 
paragraph (j):
    (A) Aftermarket service provider means any individual or business 
engaged in the diagnosis, service, and repair of a heavy-duty engine, 
who is not directly affiliated with a manufacturer or manufacturer 
franchised dealership.
    (B) Bi-directional control means the capability of a diagnostic 
tool to send messages on the data bus that temporarily overrides the 
module's control over a sensor or actuator and gives control to the 
diagnostic tool operator. Bi-directional controls do not create 
permanent changes to engine or component calibrations.
    (C) Data stream information means information (i.e., messages and 
parameters) originated within the engine by a module or intelligent 
sensors (i.e., a sensor that contains and is ontrolled by its own 
module) and transmitted between a network of modules and/or intelligent 
sensors connected in parallel with either one or more communication 
wires. The information is broadcast over the communication wires for 
use by the OBD system to gather information on emissions-related 
components or systems and from other engine modules that may impact 
emissions. For the purposes of this section, data stream information 
does not include engine calibration related information, or any data 
stream information from systems or modules that do not impact 
emissions.
    (D) Emissions-related information means any information related to 
the diagnosis, service, and repair of emissions-related components. 
Emissions-related information includes, but is not limited to, 
information regarding any system, component or part of an engine that 
controls emissions and any system, component and/or part associated 
with the engine, including, but not limited to: the engine, the fuel 
system and ignition system; information for any system, component or 
part that is likely to impact emissions, and any other information 
specified by the Administrator to be relevant to the diagnosis and 
repair of an emissions-related problem; any other information specified 
by the Administrator to be relevant for the diagnosis and repair of an 
emissions-related failure found through an evaluation of vehicles in-
use and after such finding has been communicated to the affected 
manufacturer(s).
    (E) Emissions-related training information means any information 
related training or instruction for the purpose of the diagnosis, 
service, and repair of emissions-related components.
    (F) Enhanced service and repair information means information which 
is specific for an original equipment manufacturer's brand of tools and 
equipment. This includes computer or anti-theft system initialization 
information necessary for the completion of any emissions-related 
repair on engines that employ integral security systems.
    (G) Equipment and Tool Company means a registered equipment or 
software company either public or private that is engaged in, or plans 
to engage in, the manufacture of scan tool reprogramming equipment or 
software.
    (H) Generic service and repair information means information which 
is not specific for an original equipment manufacturer's brand of tools 
and equipment.
    (I) Indirect information means any information that is not 
specifically contained in the service literature, but is contained in 
items such as tools or equipment provided to franchised dealers (or 
others). This includes computer or anti-theft system initialization 
information necessary for the completion of any emissions-related 
repair on engines that employ integral security systems.
    (J) Intermediary means any individual or entity, other than an 
original equipment manufacturer, which provides service or equipment to 
aftermarket service providers.
    (K) Manufacturer franchised dealership means any service provider 
with which a manufacturer has a direct business relationship.
    (L) Third party information provider means any individual or 
entity, other than an original equipment manufacturer, who consolidates 
manufacturer service information and makes this information available 
to aftermarket service providers.
    (M) Third party training provider means any individual or entity, 
other than an original equipment manufacturer who develops and/or 
delivers instructional and educational material for training courses.
    (4) Information dissemination. By July 1, 2010 each manufacturer 
shall provide or cause to be provided to the persons specified in 
paragraph (j)(3)(i) of this section and to any other interested parties 
a manufacturer-specific World Wide Web site containing the information 
specified in paragraph (j)(3)(i) of this section for 2010 and later 
model year engines which have been certified to the OBD requirements 
specified in Sec.  86.010-18 and are offered for sale; this requirement 
does not apply to indirect information, including the information 
specified in paragraphs (j)(13) through (j)(17) of this section. Upon 
request and approval of the Administrator, manufacturers who can 
demonstrate significant hardship in complying with this provision 
within four months after the effective date may request an additional 
six months lead time to meet this requirement. Each manufacturer Web 
site shall:
    (i) Provide access in full-text to all of the information specified 
in paragraph (j)(5) of this section.

[[Page 3323]]

    (ii) Be updated at the same time as manufacturer franchised 
dealership World Wide Web sites.
    (iii) Provide users with a description of the minimum computer 
hardware and software needed by the user to access that manufacturer's 
information (e.g., computer processor speed and operating system 
software). This description shall appear when users first log-on to the 
home page of the manufacturer's Web site.
    (iv) Provide Short-Term (24 to 72 hours), Mid-Term (30 day period), 
and Long-Term (365 day period) Web site subscription options to any 
person specified in paragraph (j)(2)(i) of this section whereby the 
user will be able to access the site, search for the information, and 
purchase, view and print the information at a fair and reasonable cost 
as specified in paragraph (j)(7) of this section for each of the 
options. In addition, for each of the tiers, manufacturers are required 
to make their entire site accessible for the respective period of time 
and price. In other words, a manufacturer may not limit any or all of 
the tiers to just one make or one model.
    (v) Allow the user to search the manufacturer Web site by various 
topics including but not limited to model, model year, key words or 
phrases, etc., while allowing ready identification of the latest 
calibration. Manufacturers who do not use model year to classify their 
engines in their service information may use an alternate delineation 
such as body series. Any manufacturer utilizing this flexibility shall 
create a cross-reference to the corresponding model year and provide 
this cross-reference on the manufacturer Web site home page.
    (vi) Provide accessibility using common, readily available software 
and shall not require the use of software, hardware, viewers, or 
browsers that are not readily available to the general public. 
Manufacturers shall also provide hyperlinks to any plug-ins, viewers or 
browsers (e.g. Adobe Acrobat or Netscape) needed to access the 
manufacturer Web site.
    (vii) Allow simple hyper-linking to the manufacturer Web site from 
Government Web sites and automotive-related Web sites.
    (viii) Posses sufficient server capacity to allow ready access by 
all users and has sufficient capacity to assure that all users may 
obtain needed information without undue delay.
    (ix) Correct or delete broken Web links on a weekly basis.
    (x) Allow for Web site navigation that does not require a user to 
return to the manufacturer home page or a search engine in order to 
access a different portion of the site.
    (xi) Allow users to print out any and all of the materials required 
to be made available on the manufacturers Web site, including the 
ability to print it at the user's location.
    (5) Small volume provisions for information dissemination.
    (i) Manufacturers with total annual sales of less than 5,000 
engines shall have until July 1, 2011 to launch their individual Web 
sites as required by paragraph (j)(4) of this section.
    (ii) Manufacturers with total annual sales of less than 1,000 
engines may, in lieu of meeting the requirement of paragraph (j)(4) of 
this section, request the Administrator to approve an alternative 
method by which the required emissions-related information can be 
obtained by the persons specified in paragraph (j)(3)(i) of this 
section.
    (6) Required information. All information relevant to the diagnosis 
and completion of emissions-related repairs shall be posted on 
manufacturer Web sites. This excludes indirect information specified in 
paragraphs (j)(7) and (j)(13) through (j)(17) of this section. To the 
extent that this information does not already exist in some form for 
their manufacturer franchised dealerships, manufacturers are required 
to develop and make available the information required by this section 
to both their manufacturer franchised dealerships and the aftermarket. 
The required information includes, but is not limited to:
    (i) Manuals, including subsystem and component manuals developed by 
a manufacturer's third party supplier that are made available to 
manufacturer franchised dealerships, technical service bulletins 
(TSBs), recall service information, diagrams, charts, and training 
materials. Manuals and other such service information from third party 
suppliers are not required to be made available in full-text on 
manufacturer Web sites as described in paragraph (j)(3) of this 
section. Rather, manufacturers must make available on the manufacturer 
Web site as required by paragraph (j)(3) of this section an index of 
the relevant information and instructions on how to order such 
information. In the alternate, a manufacturer can create a link from 
its Web site to the Web site(s) of the third party supplier.
    (ii) OBD system information which includes, but is not limited to, 
the following:
    (A) A general description of the operation of each monitor, 
including a description of the parameter that is being monitored;
    (B) A listing of all typical OBD diagnostic trouble codes 
associated with each monitor;
    (C) A description of the typical enabling conditions (either 
generic or monitor-specific) for each monitor (if equipped) to execute 
during engine operation, including, but not limited to, minimum and 
maximum intake air and engine coolant temperature, speed range, and 
time after engine startup. In addition, manufacturers shall list all 
monitor-specific OBD drive cycle information for all major OBD monitors 
as equipped including, but not limited to, catalyst, catalyst heater, 
oxygen sensor, oxygen sensor heater, evaporative system, exhaust gas 
re-circulation (EGR), secondary air, and air conditioning system. 
Additionally, for diesel engines which also perform misfire, fuel 
system and comprehensive component monitoring under specific driving 
conditions (i.e., non-continuous monitoring; as opposed to spark 
ignition engines that monitor these systems under all conditions or 
continuous monitoring), the manufacturer shall make available monitor-
specific drive cycles for these monitors. Any manufacturer who develops 
generic drive cycles, either in addition to, or instead of, monitor-
specific drive cycles shall also make these available in full-text on 
manufacturer Web sites;
    (D) A listing of each monitor sequence, execution frequency and 
typical duration;
    (E) A listing of typical malfunction thresholds for each monitor;
    (F) For OBD parameters for specific engines that deviate from the 
typical parameters, the OBD description shall indicate the deviation 
and provide a separate listing of the typical values for those engines;
    (G) Identification and scaling information necessary to interpret 
and understand data available through Diagnostic Message 8 pursuant to 
SAE Recommended Practice J1939-73, Application Layer--Diagnostics, 
revised June 2001 or through Service/Mode $06 pursuant to SAE 
Recommended Practice J1979, E/E Diagnostic Test Modes--Equivalent to 
ISO/DIS 15031-5: April 30, 2002. These documents are Incorporated by 
Reference in Sec.  86.1.
    (H) Algorithms, look-up tables, or any values associated with look-
up tables are not required to be made available.
    (iii) Any information regarding any system, component, or part of a 
engine monitored by the OBD system that could in a failure mode cause 
the OBD system to illuminate the malfunction indicator light (MIL);
    (iv) Manufacturer-specific emissions-related diagnostic trouble 
codes (DTCs)

[[Page 3324]]

and any related service bulletins, trouble shooting guides, and/or 
repair procedures associated with these manufacturer-specific DTCs; and
    (v) Information regarding how to obtain the information needed to 
perform reinitialization of any computer or anti-theft system following 
an emissions-related repair.
    (7) Anti-theft System Initialization Information. Computer or anti-
theft system initialization information and/or related tools necessary 
for the proper installation of on-board computers or necessary for the 
completion of any emissions-related repair on engines that employ 
integral security systems or the repair or replacement of any other 
emission-related part shall be made available at a fair and reasonable 
cost to the persons specified in paragraph (j)(3)(i) of this section.
    (i) Except as provided under paragraph (j)(7)(ii) of this section, 
manufacturers must make this information available to persons specified 
in paragraph (j)(3)(i) of this section, such that such persons will not 
need any special tools or manufacturer-specific scan tools to perform 
the initialization. Manufacturers may make such information available 
through, for example, generic aftermarket tools, a pass-through device, 
or inexpensive manufacturer specific cables.
    (ii) A manufacturer may request Administrator approval for an 
alternative means to re-initialize engines for some or all model years 
through the 2013 model year by 90 days following the effective date of 
the final rule. The Administrator shall approve the request only after 
the following conditions have been met:
    (A) The manufacturer must demonstrate that the availability of such 
information to aftermarket service providers would significantly 
increase the risk of theft.
    (B) The manufacturer must make available a reasonable alternative 
means to install or repair computers, or to otherwise repair or replace 
an emission-related part.
    (C) Any alternative means proposed by a manufacturer cannot require 
aftermarket technicians to use a manufacturer franchised dealership to 
obtain information or special tools to re-initialize the anti-theft 
system. All information must come directly from the manufacturer or a 
single manufacturer-specified designee.
    (D) Any alternative means proposed by a manufacturer must be 
available to aftermarket technicians at a fair and reasonable price.
    (E) Any alternative must be available to aftermarket technicians 
within twenty-four hours of the initial request.
    (F) Any alternative must not require the purchase of a special tool 
or tools, including manufacturer-specific tools, to complete this 
repair. Alternatives may include lease of such tools, but only for 
appropriately minimal cost.
    (G) In lieu of leasing their manufacturer-specific tool to meet 
this requirement, a manufacturer may also choose to release the 
necessary information to equipment and tool manufacturers for 
incorporation into aftermarket scan tools. Any manufacturer choosing 
this option must release the information to equipment and tool 
manufacturers within 60 days of Administrator approval.
    (8) Cost of required information.
    (i) All information required to be made available by this section, 
shall be made available at a fair and reasonable price. In determining 
whether a price is fair and reasonable, consideration may be given to 
relevant factors, including, but not limited to, the following:
    (A) The net cost to the manufacturer franchised dealerships for 
similar information obtained from manufacturers, less any discounts, 
rebates, or other incentive programs;
    (B) The cost to the manufacturer for preparing and distributing the 
information, excluding any research and development costs incurred in 
designing and implementing, upgrading or altering the onboard computer 
and its software or any other engine part or component. Amortized 
capital costs for the preparation and distribution of the information 
may be included;
    (C) The price charged by other manufacturers for similar 
information;
    (D) The price charged by manufacturers for similar information 
prior to the launch of manufacturer Web sites;
    (E) The ability of the average aftermarket technician or shop to 
afford the information;
    (F) The means by which the information is distributed;
    (G) The extent to which the information is used, which includes the 
number of users, and frequency, duration, and volume of use; and
    (H) Inflation.
    (ii) Manufacturers must submit to EPA a request for approval of 
their pricing structure for their Web sites and amounts to be charged 
for the information required to be made available under paragraphs 
(j)(4) and (j)(6) of this section at least 180 days in advance of the 
launch of the web site. Subsequent to the approval of the manufacturer 
Web site pricing structure, manufacturers shall notify EPA upon the 
increase in price of any one or all of the subscription options of 20 
percent or more above the previously approved price, taking inflation 
into account.
    (A) The manufacturer shall submit a request to EPA that sets forth 
a detailed description of the pricing structure and amounts, and 
support for the position that the pricing structure and amounts are 
fair and reasonable by addressing, at a minimum, each of the factors 
specified in paragraph (j)(8)(i) of this section.
    (B) EPA will act upon on the request within180 days following 
receipt of a complete request or following receipt of any additional 
information requested by EPA.
    (C) EPA may decide not to approve, or to withdraw approval for a 
manufacturer's pricing structure and amounts based on a conclusion that 
this pricing structure and/or amounts are not, or are no longer, fair 
and reasonable, by sending written notice to the manufacturer 
explaining the basis for this decision.
    (D) In the case of a decision by EPA not to approve or to withdraw 
approval, the manufacturer shall within three months following notice 
of this decision, obtain EPA approval for a revised pricing structure 
and amounts by following the approval process described in this 
paragraph.
    (9) Unavailable information. Any information which is not provided 
at a fair and reasonable price shall be considered unavailable, in 
violation of these regulations and section 202(m)(5) of the Clean Air 
Act.
    (10) Third party information providers. By January 1, 2011 
manufacturers shall, for model year 2010 and later engines, make 
available to third-party information providers as defined in paragraph 
(j)(3)(ii) of this section with whom they engage in licensing or 
business arrangements;
    (i) The required emissions-related information as specified in 
paragraph (j)(6) of this section either:
    (A) Directly in electronic format such as diskette or CD-ROM using 
non-proprietary software, in English; or
    (B) Indirectly via a Web site other than that required by paragraph 
(j)(4) of this section;
    (ii) For any manufacturer who utilizes an automated process in 
their manufacturer-specific scan tool for diagnostic fault trees, the 
data schema, detail specifications, including category types/codes and 
engine codes, and data format/content structure of the diagnostic 
trouble trees.
    (iii) Manufacturers can satisfy the requirement of paragraph 
(j)(10)(ii) of this section by making available

[[Page 3325]]

diagnostic trouble trees on their manufacturer Web sites in full-text.
    (iv) Manufacturers are not responsible for the accuracy of the 
information distributed by third parties. However, where manufacturers 
charge information intermediaries for information, whether through 
licensing agreements or other arrangements, manufacturers are 
responsible for inaccuracies contained in the information they provide 
to third party information providers.
    (11) Required emissions-related training information. By January 1, 
2011, for emissions-related training information, manufacturers shall:
    (i) Video tape or otherwise duplicate and make available for sale 
on manufacturer Web sites within 30 days after transmission any 
emissions-related training courses provided to manufacturer franchised 
dealerships via the Internet or satellite transmission;
    (ii) Provide on the manufacturer Web site an index of all 
emissions-related training information available for purchase by 
aftermarket service providers for 2010 and newer engines. The required 
information must be made available for purchase within 3 months of 
model introduction and then must be made available at the same time it 
is made available to manufacturer franchised dealerships, whichever is 
earlier. The index shall describe the title of the course or 
instructional session, the cost of the video tape or duplicate, and 
information on how to order the item(s) from the manufacturer Web site. 
All of the items available must be shipped within 24 hours of the order 
being placed and are to made available at a fair and reasonable price 
as described in paragraph (j)(8) of this section. Manufacturers unable 
to meet the 24 hour shipping requirement under circumstances where 
orders exceed supply and additional time is needed by the distributor 
to reproduce the item being ordered, may exceed the 24 hour shipping 
requirement, but in no instance can take longer than 14 days to ship 
the item.
    (iii) Provide access to third party training providers as defined 
in paragraph (j)(3)(ii) of this section all emission-related training 
courses transmitted via satellite or Internet offered to their 
manufacturer franchised dealerships. Manufacturers may not charge 
unreasonable up-front fees to third party training providers for this 
access, but may require a royalty, percentage, or other arranged fee 
based on per-use enrollment/subscription basis. Manufacturers may take 
reasonable steps to protect any copyrighted information and are not 
required to provide this information to parties that do not agree to 
such steps.
    (12) Timeliness and maintenance of information dissemination.
    (i) Subsequent to the initial launch of the manufacturer's Web 
site, manufacturers must make the information required under paragraph 
(j)(6) of this section available on their Web site within six months of 
model introduction, or at the same time it is made available to 
manufacturer franchised dealerships. After this six month period, the 
information must be available and updated on the manufacturer Web site 
at the same time that the updated information is made available to 
manufacturer franchised dealerships, except as otherwise specified in 
this section.
    (ii) Archived information. Manufacturers must maintain the required 
information on their Web sites in full-text as defined in paragraph 
(j)(6) of this section for a minimum of 15 years after model 
introduction. Subsequent to this fifteen year period, manufacturers may 
archive the information in the manufacturer's format of choice and 
provide an index of the archived information on the manufacturer Web 
site and how it can be obtained by interested parties. Manufacturers 
shall index their available information with a title that adequately 
describes the contents of the document to which it refers. 
Manufacturers may allow for the ordering of information directly from 
their Web site, or from a Web site hyperlinked to the manufacturer Web 
site. In the alternate, manufacturers shall list a phone number and 
address where aftermarket service providers can call or write to obtain 
the desired information. Manufacturers must also provide the price of 
each item listed, as well as the price of items ordered on a 
subscription basis. To the extent that any additional information is 
added or changed for these model years, manufacturers shall update the 
index as appropriate. Manufacturers will be responsible for ensuring 
that their information distributors do so within one regular business 
day of receiving the order. Items that are less than 20 pages (e.g. 
technical service bulletins) shall be faxed to the requestor and 
distributors are required to deliver the information overnight if 
requested and paid for by the ordering party. Archived information must 
be made available on demand and at a fair and reasonable price.
    (13) Recalibration Information.
    (i) Manufacturers shall make available to the persons specified in 
paragraph (j)(3)(i) of this section all emissions-related recalibration 
or reprogramming events (including driveability reprogramming events 
that may affect emissions) in the format of their choice at the same 
time they are made available to manufacturer franchised dealerships. 
This requirement takes effect on July 1, 2010.
    (ii) Manufacturers shall provide persons specified in paragraph 
(j)(3)(i) of this section with an efficient and cost-effective method 
for identifying whether the calibrations on engines are the latest to 
be issued. This requirement takes effect on July 1, 2010.
    (iii) For all 2010 and later OBD engines equipped with 
reprogramming capability, manufacturers shall comply with either SAE 
J2534, ``Recommended Practice for Pass-Thru Vehicle Programming'' , 
December 2004, or the Technology and Maintenance Council's (TMC) 
Recommended Practice RP1210A. ``WindowsTM Communication 
API'' , July 1999. These documents are Incorporated by Reference in 
Sec.  86.1.
    (iv) For model years 2010 and later, manufacturers shall make 
available to aftermarket service providers the necessary manufacturer-
specific software applications and calibrations needed to initiate 
pass-through reprogramming. This software shall be able to run on a 
standard personal computer that utilizes standard operating systems as 
specified in either J2534 or RP1210A.
    (v) Manufacturers may take any reasonable business precautions 
necessary to protect proprietary business information and are not 
required to provide this information to any party that does not agree 
to these reasonable business precautions. The requirements to make 
hardware available and to release the information to equipment and tool 
companies takes effect on July 1, 2010, and within 3 months of model 
introduction for all new model years.
    (14) Generic and enhanced information for scan tools. By July 1, 
2010, manufacturers shall make available to equipment and tool 
companies all generic and enhanced service information including bi-
directional control and data stream information as defined in paragraph 
(j)(4)(ii) of this section. This requirement applies for 2010 and later 
model year engines.
    (i) The information required by this paragraph (j)(14) shall be 
provided electronically using common document formats to equipment and 
tool companies with whom they have appropriate licensing, contractual, 
and/or confidentiality arrangements. To the extent that a central 
repository for this

[[Page 3326]]

information (e.g. the TEK-NET library developed by the Equipment and 
Tool Institute) is used to warehouse this information, the 
Administrator shall have free unrestricted access. In addition, 
information required by this paragraph (j)(14) shall be made available 
to equipment and tool companies who are not otherwise members of any 
central repository and shall have access if the non-members have 
arranged for the appropriate licensing, contractual and/or 
confidentiality arrangements with the manufacturer and/or a central 
repository.
    (ii) In addition to the generic and enhanced information defined in 
paragraph (j)(3)(ii) of this section, manufacturers shall also make 
available the following information necessary for developing generic 
diagnostic scan tools:
    (A) The physical hardware requirements for data communication (e.g. 
system voltage requirements, cable terminals/pins, connections such as 
RS232 or USB, wires, etc.)
    (B) Electronic Control Unit (ECU) data communication (e.g. serial 
data protocols, transmission speed or baud rate, bit timing 
requirements, etc),
    (C) Information on the application physical interface (API) or 
layers. (i.e., processing algorithms or software design descriptions 
for procedures such as connection, initialization, and termination),
    (D) Engine application information or any other related service 
information such as special pins and voltages or additional connectors 
that require enablement and specifications for the enablement.
    (iii) Any manufacturer who utilizes an automated process in their 
manufacturer-specific scan tool for diagnostic fault trees shall make 
available to equipment and tool companies the data schema, detail 
specifications, including category types/codes and codes, and data 
format/content structure of the diagnostic trouble trees.
    (iv) Manufacturers can satisfy the requirement of paragraph 
(j)(14)(iii) of this section by making available diagnostic trouble 
trees on their manufacturer Web sites in full-text.
    (v) Manufacturers shall make all required information available to 
the requesting equipment and tool company within 14 days after the 
request to purchase has been made unless the manufacturer requests 
Administrator approval to refuse to disclose such information to the 
requesting company or requests Administrator approval for additional 
time to comply. After receipt of a request and consultation with the 
affected parties, the Administrator shall either grant or refuse the 
petition based on the evidence submitted during the consultation 
process:
    (A) If the evidence demonstrates that the engine manufacturer has a 
reasonably based belief that the requesting equipment and tool company 
could not produce safe and functionally accurate tools that would not 
cause damage to the engine, the petition for non-disclosure will be 
granted. Engine manufacturers are not required to provide data stream 
and bi-directional control information that would permit an equipment 
and tool company's products to modify an EPA-certified engine or 
transmission configuration.
    (B) If the evidence does not demonstrate that the engine 
manufacturer has a reasonably-based belief that the requesting 
equipment and tool company could not produce safe and functionally 
accurate tools that would not cause damage to the engine, the petition 
for non-disclosure will be denied and the engine manufacturer, as 
applicable, shall make the requested information available to the 
requesting equipment and tool company within 2 days of the denial.
    (vi) If the manufacturer submits a request for Administrator 
approval for additional time, and satisfactorily demonstrates to the 
Administrator that the engine manufacturer is able to comply but 
requires additional time within which to do so, the Administrator shall 
grant the request and provide additional time to fully and 
expeditiously comply.
    (vii) Manufacturers may require that tools using information 
covered under paragraph (j)(14) of this section comply with the 
Component Identifier message specified in SAE J1939-71 as Parameter 
Group Number (PGN) 65249 (including the message parameter's make, 
model, and serial number) and the SAE J1939-81 Address Claim PGN.
    (15) Availability of manufacturer-specific scan tools. 
Manufacturers shall make available for sale to the persons specified in 
paragraph (j)(3)(i) of this section their own manufacturer-specific 
diagnostic tools at a fair and reasonable cost. These tools shall also 
be made available in a timely fashion either through the manufacturer 
Web site or through a manufacturer-designated intermediary. 
Manufacturers shall ship purchased tools in a timely manner after a 
request and training, if any, has been completed. Any required training 
materials and classes must be made available at a fair and reasonable 
price. Manufacturers who develop different versions of one or more of 
their diagnostic tools that are used in whole or in part for emission-
related diagnosis and repair shall also insure that all emission-
related diagnosis and repair information is available for sale to the 
aftermarket at a fair and reasonable cost. Factors for determining fair 
and reasonable cost include, but are not limited to:
    (i) The net cost to the manufacturer's franchised dealerships for 
similar tools obtained from manufacturers, less any discounts, rebates, 
or other incentive programs;
    (ii) The cost to the manufacturer for preparing and distributing 
the tools, excluding any research and development costs;
    (iii) The price charged by other manufacturers of similar sizes for 
similar tools;
    (iv) The capabilities and functionality of the manufacturer tool;
    (v) The means by which the tools are distributed;
    (vi) Inflation;
    (vii) The ability of aftermarket technicians and shops to afford 
the tools. Manufacturers shall provide technical support to aftermarket 
service providers for the tools described in this section, either 
themselves or through a third-party of their choice.
    (16) Changing content of manufacturer-specific scan tools. 
Manufacturers who opt to remove non-emissions related content from 
their manufacturer-specific scan tools and sell them to the persons 
specified in paragraph (j)(3)(i) of this section shall adjust the cost 
of the tool accordingly lower to reflect the decreased value of the 
scan tool. All emissions-related content that remains in the 
manufacturer-specific tool shall be identical to the information that 
is contained in the complete version of the manufacturer specific tool. 
Any manufacturer who wishes to implement this option must request 
approval from the Administrator prior to the introduction of the tool 
into commerce.
    (17) Reference Materials. Manufacturers shall conform with the 
following Society of Automotive Engineers (SAE) standards. These 
documents are incorporated by reference in Sec.  86.1.
    (i) For Web-based delivery of service information, manufacturers 
shall comply with SAE Recommended Practice J2403, Medium/Heavy-Duty E/E 
Systems Diagnosis Nomenclature; August 2004. This recommended practice 
standardizes various terms, abbreviations, and acronyms associated with 
on-board diagnostics. Manufacturers shall comply with SAE J2403 
beginning with the Model Year 2013.

[[Page 3327]]

    (ii) For identification and scaling information necessary to 
interpret and understand data available through Diagnostic Message 8, 
manufacturers shall comply with SAE Recommended Practice J1939-73, 
Application Layer--Diagnostics, revised June 2001. In the alternate, 
manufacturers may comply with Service/Mode $06 pursuant to SAE 
Recommended Practice J1979, E/E Diagnostic Test Modes--Equivalent to 
ISO/DIS 15031-5: April 30, 2002. These recommended practices describe 
the implementation of diagnostic test modes for emissions related test 
data. Manufacturers shall comply with either SAE J1939-73 or SAE J1979 
beginning with Model Year 2013. These recommended practices describe 
the implementation of diagnostic test modes for emissions related test 
data.
    (iii) For pass-thru reprogramming capabilities, manufacturers shall 
comply with Technology and Maintenance Council's (TMC) Recommended 
Practice RP1210A, ``WindowsTM Communication API'' , July 
1999. In the alternate, manufacturers may comply with SAE J2534, 
Recommended Practice for Pass-Thru Vehicle Programming, December 2004. 
These recommended practices provide technical specifications and 
information that manufacturers must supply to equipment and tool 
companies to develop aftermarket pass-thru reprogramming tools. 
Manufacturers shall comply with either RP1210A or SAE J2534 beginning 
with Model Year 2013.
    (18) Reporting Requirements. Performance reports that adequately 
demonstrate that each manufacturer's Web site meets the information 
requirements outlined in paragraphs (j)(6)(i) through (j)(6)(vi) of 
this section shall be submitted to the Administrator annually or upon 
request by the Administrator. These reports shall indicate the 
performance and effectiveness of the Web sites by using commonly used 
Internet statistics (e.g., successful requests, frequency of use, 
number of subscriptions purchased, etc.) Manufacturers shall provide to 
the Administrator reports on an annual basis within 30 days of the end 
of the calendar year. These annual reports shall be submitted to the 
Administrator electronically utilizing non-proprietary software in the 
format as agreed to by the Administrator and the manufacturers.
    (19) Prohibited Acts, Liability and Remedies.
    (i) It is a prohibited act for any person to fail to promptly 
provide or cause a failure to promptly provide information as required 
by this paragraph (j), or to otherwise fail to comply or cause a 
failure to comply with any provision of this subsection.
    (ii) Any person who fails or causes the failure to comply with any 
provision of this paragraph (j) is liable for a violation of that 
provision. A corporation is presumed liable for any violations of this 
subpart that are committed by any of its subsidiaries, affiliates or 
parents that are substantially owned by it or substantially under its 
control.
    (iii) Any person who violates a provision of this paragraph (j) 
shall be subject to a civil penalty of not more than $31,500 per day 
for each violation. This maximum penalty is shown for calendar year 
2002. Maximum penalty limits for later years may be set higher based on 
the Consumer Price Index, as specified in 40 CFR part 19. In addition, 
such person shall be liable for all other remedies set forth in Title 
II of the Clean Air Act, remedies pertaining to provisions of Title II 
of the Clean Air Act, or other applicable provisions of law.
    10. Section 86.013-2 is added to Subpart A to read as follows:


Sec.  86.013-2  Definitions.

    The definitions of Sec.  86.004-2 continue to apply to 2004 and 
later model year vehicles, and the definitions of Sec.  86.010-2 
continue to apply to 2010 and later model year vehicles. The 
definitions listed in this section apply beginning with the 2013 model 
year.
    Onboard Diagnostics (OBD) group means a combination of engines, 
engine families, or engine ratings that use the same OBD strategies and 
similar calibrations.
    11. Section 86.013-17 is added to Subpart A to read as follows:


Sec.  86.013-17  On-board Diagnostics for engines used in applications 
less than or equal to 14,000 pounds GVWR.

    Section 86.013-17 includes text that specifies requirements that 
differ from Sec.  86.005-17, Sec.  86.007-17, and Sec.  86.010-17. 
Where a paragraph in Sec.  86.005-17 or Sec.  86.007-17 or Sec.  
86.010-17 is identical and applicable to Sec.  86.013-17, this may be 
indicated by specifying the corresponding paragraph and the statement 
``[Reserved]. For guidance see Sec.  86.005-17.'' or ``[Reserved]. For 
guidance see Sec.  86.007-17.'' or ``[Reserved]. For guidance see Sec.  
86.010-17.''
    (a) through (b)(1)(i) [Reserved]. For guidance see Sec.  86.010-17.
    (b)(1)(ii) Diesel.
    (A) If equipped, reduction catalyst deterioration or malfunction 
before it results in exhaust NOX emissions exceeding the 
applicable NOX FEL+0.3 g/bhp-hr. If equipped, oxidation 
catalyst deterioration or malfunction before it results in exhaust NMHC 
emissions exceeding 2 times the applicable NMHC standard. These 
catalyst monitoring requirements need not be done if the manufacturer 
can demonstrate that deterioration or malfunction of the system will 
not result in exceedance of the threshold.
    (B) If equipped, diesel particulate trap deterioration or 
malfunction before it results in exhaust emissions exceeding any of the 
following levels: the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr 
PM, whichever is higher; or, exhaust NMHC emissions exceeding 2 times 
the applicable NMHC standard. Catastrophic failure of the particulate 
trap must also be detected. In addition, the absence of the particulate 
trap or the trapping substrate must be detected.
    (b)(2) [Reserved]. For guidance see Sec.  86.005-17.
    (b)(3)(i) Oxygen sensors and air-fuel ratio sensors downstream of 
aftertreatment devices.
    (A) Otto-cycle. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding 1.5 times the applicable 
standard or FEL for NMHC, NOX or CO.
    (B) Diesel. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding any of the following levels: 
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is 
higher; or, the applicable NOX FEL+0.3 g/bhp-hr; or, 2 times 
the applicable NMHC standard.
    (ii) Oxygen sensors and air-fuel ratio sensors upstream of 
aftertreatment devices.
    (A) Otto-cycle. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding 1.5 times the applicable 
standard or FEL for NMHC, NOX or CO.
    (B) Diesel. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding any of the following levels: 
the applicable PM FEL+0.02 g/bhp-hr or 0.03 g/bhp-hr PM, whichever is 
higher; or, the applicable NOX FEL+0.3 g/bhp-hr; or, 2 times 
the applicable NMHC standard; or, 2 times the applicable CO standard.
    (iii) NOX sensors.
    (A) Otto-cycle. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding 1.5 times the applicable 
standard or FEL for NMHC, NOX or CO.
    (B) Diesel. If equipped, sensor deterioration or malfunction 
resulting in exhaust emissions exceeding any of the following levels: 
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is 
higher; or, the applicable NOX FEL+0.3 g/bhp-hr.

[[Page 3328]]

    (b)(4) [Reserved]. For guidance see Sec.  86.005-17.
    (b)(5) Other emission control systems and components.
    (i) Otto-cycle. Any deterioration or malfunction occurring in an 
engine system or component directly intended to control emissions, 
including but not necessarily limited to, the exhaust gas recirculation 
(EGR) system, if equipped, the secondary air system, if equipped, and 
the fuel control system, singularly resulting in exhaust emissions 
exceeding 1.5 times the applicable emission standard or FEL for NMHC, 
NOX or CO. For engines equipped with a secondary air system, 
a functional check, as described in Sec. 86.005-17(b)(6), may satisfy 
the requirements of this paragraph (b)(5) provided the manufacturer can 
demonstrate that deterioration of the flow distribution system is 
unlikely. This demonstration is subject to Administrator approval and, 
if the demonstration and associated functional check are approved, the 
diagnostic system must indicate a malfunction when some degree of 
secondary airflow is not detectable in the exhaust system during the 
check. For engines equipped with positive crankcase ventilation (PCV), 
monitoring of the PCV system is not necessary provided the manufacturer 
can demonstrate to the Administrator's satisfaction that the PCV system 
is unlikely to fail.
    (ii) Diesel. Any deterioration or malfunction occurring in an 
engine system or component directly intended to control emissions, 
including but not necessarily limited to, the exhaust gas recirculation 
(EGR) system, if equipped, and the fuel control system, singularly 
resulting in exhaust emissions exceeding any of the following levels: 
the applicable PM FEL+0.02 g/bhp-hr or 0.03 g/bhp-hr PM, whichever is 
higher; or, the applicable NOX FEL+0.3 g/bhp-hr; or, 2 times 
the applicable NMHC standard; or, 2 times the applicable CO standard. A 
functional check, as described in Sec. 86.005-17(b)(6), may satisfy the 
requirements of this paragraph (b)(5) provided the manufacturer can 
demonstrate that a malfunction would not cause emissions to exceed the 
applicable levels. This demonstration is subject to Administrator 
approval. For engines equipped with crankcase ventilation (CV), 
monitoring of the CV system is not necessary provided the manufacturer 
can demonstrate to the Administrator's satisfaction that the CV system 
is unlikely to fail.
    (b)(6) through (j) [Reserved]. For guidance see Sec.  86.010-17.
    (k) [Reserved.]
    12. Section 86.013-18 is added to Subpart A to read as follows:


Sec.  86.013-18  On-board Diagnostics for engines used in applications 
greater than 14,000 pounds GVWR.

    Section 86.013-18 includes text that specifies requirements that 
differ from Sec.  86.010-18. Where a paragraph in Sec.  86.010-18 is 
identical and applicable to Sec.  86.013-18, this may be indicated by 
specifying the corresponding paragraph and the statement ``[Reserved]. 
For guidance see Sec.  86.010-18.'' However, where a paragraph in Sec.  
86.010-18 is identical and applicable to Sec.  86.013-18, and there 
appears the statement ``[Reserved]. For guidance see Sec.  86.010-18,'' 
it shall be understood that any referenced tables within Sec.  86.010-
18 shall actually refer to the applicable table shown in Sec.  86.013-
18.
    (a) General. All heavy-duty engines intended for use in a heavy-
duty vehicle weighing more than 14,000 pounds GVWR must be equipped 
with an on-board diagnostic (OBD) system capable of monitoring all 
emission-related engine systems or components during the life of the 
engine. The OBD system is required to detect all malfunctions specified 
in paragraphs (g), and (i) of this section and paragraph (h) of Sec.  
86.010-18 although the OBD system is not required to use a unique 
monitor to detect each of those malfunctions.
    (a)(1) [Reserved]. For guidance see Sec.  86.010-18.
    (a)(2) The OBD system must be equipped with a standardized data 
link connector to provide access to the stored DTCs as specified in 
paragraph (k)(2) of this section.
    (a)(3) and (a)(4) [Reserved]. For guidance see Sec.  86.010-18.
    (b) Malfunction indicator light (MIL) and Diagnostic Trouble Codes 
(DTC). The OBD system must incorporate a malfunction indicator light 
(MIL) or equivalent and must store specific types of diagnostic trouble 
codes (DTC).
    (1) MIL specifications.
    (i) The MIL must be located on the driver's side instrument panel 
and be of sufficient illumination and location to be readily visible 
under all lighting conditions. The MIL must be amber (yellow) in color; 
the use of red for the OBD-related MIL is prohibited. More than one 
general purpose malfunction indicator light for emission-related 
problems shall not be used; separate specific purpose warning lights 
(e.g., brake system, fasten seat belt, oil pressure, etc.) are 
permitted. When activated, the MIL must display the engine symbol 
designated as F01 by the International Standards Organization (ISO) in 
``Road vehicles--Symbols for controls, indicators and tell-tales,'' ISO 
2575:2004.
    (b)(1)(ii) through (b)(1)(iv) [Reserved]. For guidance see Sec.  
86.010-18.
    (b)(1)(v) The MIL required by this paragraph (b) must not be used 
in any other way than is specified in this section.
    (b)(2) [Reserved]. For guidance see Sec.  86.010-18.
    (b)(3) MIL deactivation and DTC erasure protocol.
    (i) Deactivating the MIL. Except as otherwise provided for in 
paragraph (g)(2)(iv)(E) of this section and Sec.  86.010-
18(g)(6)(iv)(B) for diesel misfire malfunctions and empty reductant 
tanks, and paragraphs (h)(1)(iv)(F), (h)(2)(viii), and (h)(7)(iv)(B) of 
Sec.  86.010-18 for gasoline fuel system, misfire, and evaporative 
system malfunctions, once the MIL has been activated, it may be 
deactivated after three subsequent sequential drive cycles during which 
the monitoring system responsible for activating the MIL functions and 
the previously detected malfunction is no longer present and provided 
no other malfunction has been detected that would independently 
activate the MIL according to the requirements outlined in Sec.  
86.010-18(b)(2).
    (b)(3)(ii) through (b)(4) [Reserved.] For guidance see Sec.  
86.010-18.
    (c) Monitoring conditions. The OBD system must monitor and detect 
the malfunctions specified in paragraphs (g) and (i) of this section 
and Sec.  86.010-18(h) under the following general monitoring 
conditions. The more specific monitoring conditions of paragraph (d) of 
this section are sometimes required according to the provisions of 
paragraphs (g) and (i) of this section and Sec. 86.010-18(h).
    (1) As specifically provided for in paragraphs (g) and (i) of this 
section and Sec.  86.010-18(h), the monitoring conditions for detecting 
malfunctions must be technically necessary to ensure robust detection 
of malfunctions (e.g. avoid false passes and false indications of 
malfunctions); designed to ensure monitoring will occur under 
conditions that may reasonably be expected to be encountered in normal 
vehicle operation and normal vehicle use; and, designed to ensure 
monitoring will occur during the FTP transient test cycle contained in 
Appendix I paragraph (f), of this part, or similar drive cycle as 
approved by the Administrator.
    (c)(2) [Reserved]. For guidance see Sec.  86.010-18.
    (c)(3) Manufacturers may request approval to define monitoring 
conditions that are not encountered during the FTP cycle as required in 
paragraph (c)(1) of this section. In

[[Page 3329]]

evaluating the manufacturer's request, the Administrator will consider 
the degree to which the requirement to run during the FTP transient 
cycle restricts monitoring during in-use operation, the technical 
necessity for defining monitoring conditions that are not encountered 
during the FTP cycle, data and/or an engineering evaluation submitted 
by the manufacturer that demonstrate that the component/system does not 
normally function during the FTP, whether monitoring is otherwise not 
feasible during the FTP cycle, and/or the ability of the manufacturer 
to demonstrate that the monitoring conditions satisfy the minimum 
acceptable in-use monitor performance ratio requirement as defined in 
paragraph (d)(1)(ii) of this section.
    (d) through (d)(1)(i) [Reserved]. For guidance see Sec.  86.010-18.
    (d)(1)(ii) Manufacturers must define monitoring conditions that, in 
addition to meeting the criteria in paragraph (c)(1) of this section 
and Sec.  86.010-18(d) through (d)(1)(i), ensure that the monitor 
yields an in-use performance ratio (as defined in Sec.  86.010-18(d)(2) 
that meets or exceeds the minimum acceptable in-use monitor performance 
ratio of 0.100 for all monitors specifically required in paragraphs (g) 
and (i) of this section and Sec.  86.010-18(h) to meet the monitoring 
condition requirements in Sec.  86.010-(18)(d)(1)(i).
    (iii) If the most reliable monitoring method developed requires a 
lower ratio for a specific monitor than that specified in paragraph 
(d)(1)(ii) of this section, the Administrator may lower the minimum 
acceptable in-use monitoring performance ratio.
    (d)(2) through (d)(3)(iv) [Reserved]. For guidance see Sec.  
86.010-18.
    (d)(3)(v) Manufacturers that use alternative statistical MIL 
activation protocols as allowed in Sec.  86.010-18(b)(2)(iii) for any 
of the monitors requiring a numerator, are required to increment the 
numerator(s) appropriately. The manufacturer may be required to provide 
supporting data and/or engineering analyses demonstrating both the 
equivalence of their incrementing approach to the incrementing 
specified in this paragraph (d)(3) for monitors using the standard MIL 
activation protocol, and the overall equivalence of the incrementing 
approach in determining that the minimum acceptable in-use performance 
ratio of paragraph (d)(1)(ii) of this section has been satisfied.
    (d)(4) through (f) [Reserved]. For guidance see Sec.  86.010-18.
    (g) OBD monitoring requirements for diesel-fueled/compression-
ignition engines. The following table shows the thresholds at which 
point certain components or systems, as specified in this paragraph 
(g), are considered malfunctioning.

  Table 1.--OBD Emissions Thresholds for Diesel-Fueled/Compression Ignition Engines Meant for Engines Placed in
                             Applications Greater Than 14,000 Pounds GVWR (g/bhp-hr)
----------------------------------------------------------------------------------------------------------------
                                  Sec.   86.010-
           Component               18 reference         NMHC              CO              NOX             PM
----------------------------------------------------------------------------------------------------------------
NMHC catalyst system...........  (g)(5).........  2x.............  ...............  ...............  ...........
NOX aftertreatment system......  (g)(6).........  ...............  ...............  +0.3...........  ...........
                                 (g)(7)
Diesel particulate filter (DPF)  (g)(8).........  2x.............  ...............  ...............   0.05/+0.04
 system.
Air-fuel ratio sensors upstream  (g)(9).........  2x.............  2x.............  +0.3...........   0.03/+0.02
 of aftertreatment devices.
Air-fuel ratio sensors           (g)(9).........  2x.............  ...............  +0.3...........   0.05/+0.04
 downstream of aftertreatment
 devices.
NOX sensors....................  (g)(9).........  ...............  ...............  +0.3...........   0.05/+0.04
``Other monitors'' with          (g)(1).........  2x.............  2x.............  +0.3...........   0.03/+0.02
 emissions thresholds.           (g)(2).........
                                 (g)(3)
                                 (g)(4)
                                 (g)(10)
----------------------------------------------------------------------------------------------------------------
Notes: FEL=Family Emissions Limit; 2x std means a multiple of 2 times the applicable emissions standard; +0.3
  means the standard or FEL plus 0.3; 0.05/+0.04 means an absolute level of 0.05 or an additive level of the
  standard or FEL plus 0.04, whichever level is higher; these emissions thresholds apply to the monitoring
  requirements of paragraph (g) of this Sec.   86.013-18.

    (1) Fuel system monitoring.
    (g)(1)(i) through (g)(1)(iii)(A) [Reserved]. For guidance see Sec.  
86.010-18.
    (g)(1)(iii)(B) The manufacturer must define the monitoring 
conditions for malfunctions identified in Sec.  86.010-18(g)(1)(ii)(B) 
and (g)(1)(ii)(C) and Table 1 of paragraph (g) of this section in 
accordance with paragraphs (c) and (d) of this section.
    (iv) Fuel system MIL activation and DTC storage. The MIL must 
activate and DTCs must be stored according to the provisions of 
paragraph (b) of this section.
    (2) Engine misfire monitoring.
    (g)(2)(i) [Reserved]. For guidance see Sec.  86.010-18.
    (g)(2)(ii) Engine misfire malfunction criteria.
    (A) The OBD system must be capable of detecting misfire occurring 
in one or more cylinders. To the extent possible without adding 
hardware for this specific purpose, the OBD system must also identify 
the specific misfiring cylinder. If more than one cylinder is 
continuously misfiring, a separate DTC must be stored indicating that 
multiple cylinders are misfiring. When identifying multiple cylinder 
misfire, the OBD system is not required to identify individually 
through separate DTCs each of the continuously misfiring cylinders.
    (B) On engines equipped with sensors that can detect combustion or 
combustion quality (e.g., for use in engines with homogeneous charge 
compression ignition (HCCI) control systems), the OBD system must 
detect a misfire malfunction causing emissions to exceed the applicable 
thresholds for ``other monitors'' shown in Table 1 of this paragraph 
(g). To determine what level of misfire would cause emissions to exceed 
the applicable emissions thresholds, the manufacturer must determine 
the percentage of misfire evaluated in 1,000 revolution increments that 
would cause emissions from an emission durability demonstration engine 
to exceed the emissions thresholds if the percentage of misfire were 
present from the beginning of the test. To establish this percentage of 
misfire, the manufacturer must use misfire events occurring at equally 
spaced, complete engine cycle intervals, across randomly selected 
cylinders throughout each 1,000-revolution increment. If this 
percentage

[[Page 3330]]

of misfire is determined to be lower than one percent, the manufacturer 
may set the malfunction criteria at one percent. Any misfire 
malfunction must be detected if the percentage of misfire established 
via this testing is exceeded regardless of the pattern of misfire 
events (e.g., random, equally spaced, continuous). The manufacturer may 
employ other revolution increments besides the 1,000 revolution 
increment. To do so, the manufacturer must demonstrate that the 
strategy is equally effective and timely in detecting misfire.
    (iii) Engine misfire monitoring conditions.
    (g)(2)(iii)(A) and (g)(2)(iii)(B) [Reserved]. For guidance see 
Sec.  86.010-18.
    (g)(2)(iii)(C) For engines equipped with sensors that can detect 
combustion or combustion quality the OBD system must monitor 
continuously for engine misfire under all positive torque engine speed 
and load conditions. If a monitoring system cannot detect all misfire 
patterns under all required engine speed and load conditions, the 
manufacturer may request that the Administrator approve the monitoring 
system nonetheless. In evaluating the manufacturer's request, the 
Administrator will consider the following factors: the magnitude of the 
region(s) in which misfire detection is limited; the degree to which 
misfire detection is limited in the region(s) (i.e., the probability of 
detection of misfire events); the frequency with which said region(s) 
are expected to be encountered in-use; the type of misfire patterns for 
which misfire detection is troublesome; and demonstration that the 
monitoring technology employed is not inherently incapable of detecting 
misfire under required conditions (i.e., compliance can be achieved on 
other engines). The evaluation will be based on the following misfire 
patterns: equally spaced misfire occurring on randomly selected 
cylinders; single cylinder continuous misfire; and, paired cylinder 
(cylinders firing at the same crank angle) continuous misfire.
    (iv) Engine misfire MIL activation and DTC storage.
    (A) General requirements for MIL activation and DTC storage are set 
forth in paragraph (b) of this section.
    (B) For engines equipped with sensors that can detect combustion or 
combustion quality, upon detection of the percentage of misfire 
specified in paragraph (g)(2)(ii)(B) of this section, the following 
criteria shall apply for MIL activation and DTC storage: A pending DTC 
must be stored no later than after the fourth exceedance of the 
percentage of misfire specified in paragraph (g)(2)(ii) of this section 
during a single drive cycle; if a pending fault code has been stored, 
the OBD system must activate the MIL and store a MIL-on DTC within 10 
seconds if the percentage of misfire specified in paragraph (g)(2)(ii) 
of this section is again exceeded four times during the drive cycle 
immediately following storage of the pending DTC, regardless of the 
conditions encountered during the drive cycle, or on the next drive 
cycle in which similar conditions are encountered to those that were 
occurring when the pending DTC was stored. Similar conditions means an 
engine speed within 375 rpm, engine load within 20 percent, and the 
same warm up status (i.e., cold or hot). The Administrator may approve 
other definitions of similar conditions based on comparable timeliness 
and reliability in detecting similar engine operation. The pending DTC 
may be erased at the end of the next drive cycle in which similar 
conditions are encountered to those that were occurring when the 
pending DTC was stored provided the specified percentage of misfire was 
not again exceeded. The pending DTC may also be erased if similar 
conditions are not encountered during the 80 drive cycles immediately 
following initial detection of the malfunction.
    (C) For engines equipped with sensors that can detect combustion or 
combustion quality, the OBD system must store and erase freeze frame 
conditions either in conjunction with storing and erasing a pending DTC 
or in conjunction with storing and erasing a MIL-on DTC. If freeze 
frame conditions are stored for a malfunction other than a misfire 
malfunction when a DTC is stored as specified in paragraph 
(g)(2)(iv)(B) of this section, the stored freeze frame information must 
be replaced with the freeze frame information regarding the misfire 
malfunction.
    (D) For engines equipped with sensors that can detect combustion or 
combustion quality, upon detection of misfire according to paragraph 
(g)(2)(iv)(B) of this section, the OBD system must also store the 
following engine conditions: engine speed, load, and warm up status of 
the first misfire event that resulted in the storage of the pending 
DTC.
    (E) For engines equipped with sensors that can detect combustion or 
combustion quality, the MIL may be deactivated after three sequential 
drive cycles in which similar conditions have been encountered without 
an exceedance of the specified percentage of misfire.
    (3) EGR system monitoring.
    (g)(3)(i) and (g)(3)(ii) [Reserved]. For guidance see Sec.  86.010-
18.
    (g)(3)(iii) EGR system monitoring conditions.
    (g)(3)(iii)(A) [Reserved]. For guidance see Sec.  86.010-18.
    (g)(3)(iii)(B) The manufacturer must define the monitoring 
conditions for malfunctions identified in Sec.  86.010-18(g)(3)(ii)(C) 
and Table 1 of paragragh (g) of this section in accordance with 
paragraphs (c) and (d) of this section, with the exception that 
monitoring must occur every time the monitoring conditions are met 
during the drive cycle rather than once per drive cycle as required in 
Sec.  86.010-18(c)(2). For purposes of tracking and reporting as 
required in Sec.  86.010-18(d) through (d)(1)(i), all monitors used to 
detect malfunctions identified in Sec.  86.010-18(g)(3)(ii)(C) and 
Table 1 of paragraph (g) of this section must be tracked separately but 
reported as a single set of values as specified in Sec.  86.010-
18(e)(1)(iii).
    (C) The manufacturer must define the monitoring conditions for 
malfunctions identified in Sec.  86.010-18(g)(3)(ii)(E) and Table 1 of 
paragraph (g) of this section in accordance with paragraphs (c) and (d) 
of this section. For purposes of tracking and reporting as required in 
Sec.  86.010-18(d) through (d)(1)(i), all monitors used to detect 
malfunctions identified in Sec.  86.010-18(g)(3)(ii)(E) and Table 1 of 
paragraph (g) of this section must be tracked separately but reported 
as a single set of values as specified in Sec.  86.010-18(e)(1)(iii).
    (g)(3)(iii)(D) [Reserved]. For guidance see Sec.  86.010-18.
    (g)(3)(iv) EGR system MIL activation and DTC storage. The MIL must 
activate and DTCs must be stored according to the provisions of 
paragraph (b) of this section.
    (4) Turbo boost control system monitoring.
    (g)(4)(i) and (g)(4)(ii) [Reserved]. For guidance see Sec.  86.010-
18.
    (g)(4)(iii) Turbo boost control system monitoring conditions.
    (g)(4)(iii)(A) [Reserved]. For guidance see Sec.  86.010-18.
    (g)(iii)(3)(B) The manufacturer must define the monitoring 
conditions for malfunctions identified in Sec.  86.010-18(g)(4)(ii)(C) 
and Table 1 of paragraph (g) of this section in accordance with 
paragraphs (c) and (d) of this section, with the exception that 
monitoring must occur every time the monitoring conditions are met 
during the drive cycle rather than once per drive cycle as required in 
Sec.  86.010-18(c)(2). For purposes of tracking and reporting as 
required in Sec.  86.010-18(d) through (d)(1)(i), all monitors used to 
detect

[[Page 3331]]

malfunctions identified in Sec.  86.010-18(g)(4)(ii)(C) and Table 1 of 
paragraph (g) of this section must be tracked separately but reported 
as a single set of values as specified in Sec.  86.010-18(e)(1)(iii).
    (C) The manufacturer must define the monitoring conditions for 
malfunctions identified in Sec.  86.010-18(g)(4)(ii)(E) and Table 1 of 
paragraph (g) of this section in accordance with paragraphs (c) and (d) 
of this section. For purposes of tracking and reporting as required in 
Sec.  86.010-18(d) through (d)(1)(i), all monitors used to detect 
malfunctions identified in Sec.  86.010-18(g)(4)(ii)(E) and Table 1 of 
paragraph (g) of this section must be tracked separately but reported 
as a single set of values as specified in Sec.  86.010-18(e)(1)(iii).
    (iv) Turbo boost system MIL activation and DTC storage. The MIL 
must activate and DTCs must be stored according to the provisions of 
paragraph (b) of this section.
    (5) NMHC converting catalyst monitoring.
    (g)(5)(i) and (g)(5)(ii) [Reserved]. For guidance see Sec.  86.010-
18.
    (g)(5)(iii) NMHC converting catalyst monitoring conditions. The 
manufacturer must define the monitoring conditions for malfunctions 
identified in Sec.  86.010-18(g)(5)(ii)(A) and (g)(5)(ii)(B) and Table 
1 of paragraph (g) of this section in accordance with paragraphs (c) 
and (d) of this section. For purposes of tracking and reporting as 
required in Sec.  86.010-18(d) through (d)(1)(i), all monitors used to 
detect malfunctions identified in Sec.  86.010-18(g)(5)(ii)(A) and 
(g)(5)(ii)(B) and Table 1 of paragraph (g) of this section must be 
tracked separately but reported as a single set of values as specified 
in Sec.  86.010-18(e)(1)(iii).
    (iv) NMHC converting catalyst MIL activation and DTC storage. The 
MIL must activate and DTCs must be stored according to the provisions 
of paragraph (b) of this section. The monitoring method for the NMHC 
converting catalyst(s) must be capable of detecting all instances, 
except diagnostic self-clearing, when a catalyst DTC has been erased 
but the catalyst has not been replaced (e.g., catalyst over-temperature 
histogram approaches are not acceptable).
    (6) Selective catalytic reduction (SCR) and lean NOX 
catalyst monitoring.
    (g)(6)(i) and (g)(6)(ii) [Reserved]. For guidance see Sec.  86.010-
18
    (g)(6)(iii) SCR and lean NOX catalyst monitoring 
conditions.
    (A) The manufacturers must define the monitoring conditions for 
malfunctions identified in Sec.  86.010-18(g)(6)(ii)(A) and Table 1 of 
paragraph (g) of this section in accordance with paragraphs (c) and (d) 
of this section. For purposes of tracking and reporting as required in 
Sec.  86.010-18(d) through (d)(1)(i), all monitors used to detect 
malfunctions identified in Sec.  86.010-18(g)(6)(ii)(A) and Table 1 of 
paragraph (g) of this section must be tracked separately but reported 
as a single set of values as specified in Sec.  86.010-18(e)(1)(iii).
    (g)(6)(iii)(B) [Reserved]. For guidance see Sec.  86.010-18.
    (g)(6)(iv) SCR and lean NOX catalyst MIL activation and 
DTC storage.
    (A) For malfunctions identified in Sec.  86.010-18(g)(6)(ii)(A) and 
Table 1 of paragraph (g) of this section, the MIL must activate and 
DTCs must be stored according to the provisions of paragraph (b) of 
this section.
    (g)(6)(iv)(B) and (g)(6)(iv)(C) [Reserved]. For guidance see Sec.  
86.010-18.
    (g)(7) NOX adsorber system monitoring.
    (g)(7)(i) and (g)(7)(ii) [Reserved]. For guidance see Sec.  86.010-
18.
    (g)(7)(iii) NOX adsorber system monitoring conditions.
    (A) The manufacturer must define the monitoring conditions for 
malfunctions identified in Sec.  86.010-18(g)(7)(ii)(A) and Table 1 of 
paragraph (g) of this section in accordance with paragraphs (c) and (d) 
of this section. For purposes of tracking and reporting as required in 
Sec.  86.010-18(d) through (d)(1)(i), all monitors used to detect 
malfunctions identified in Sec.  86.010-18(g)(7)(ii)(A) and Table 1 of 
paragraph (g) of this section must be tracked separately but reported 
as a single set of values as specified in of Sec.  86.010-
18(e)(1)(iii).
    (g)(7)(iii)(B) [Reserved]. For guidance see Sec.  86.010-18.
    (g)(7)(iv) NOX adsorber system MIL activation and DTC storage. The 
MIL must activate and DTCs must be stored according to the provisions 
of paragraph (b) of this section.
    (8) Diesel particulate filter (DPF) system monitoring.
    (g)(8)(i) and (g)(8)(ii) [Reserved]. For guidance see Sec.  86.010-
18.
    (g)(8)(iii) DPF monitoring conditions. The manufacturer must define 
the monitoring conditions for malfunctions identified in Sec.  86.010-
18(g)(8)(ii) and Table 1 of paragraph (g) of this section in accordance 
with paragraphs (c) and (d) of this section, with the exception that 
monitoring must occur every time the monitoring conditions are met 
during the drive cycle rather than once per drive cycle as required in 
Sec.  86.010-18(c)(2). For purposes of tracking and reporting as 
required in Sec.  86.010-18(d) through (d)(1)(i), all monitors used to 
detect malfunctions identified in Sec.  86.010-18(g)(8)(ii) and Table 1 
of paragraph (g) of this section must be tracked separately but 
reported as a single set of values as specified in Sec.  86.010-
18(e)(1)(iii).
    (iv) DPF system MIL activation and DTC storage. The MIL must 
activate and DTCs must be stored according to the provisions of 
paragraph (b) of this section.
    (9) Exhaust gas sensor and sensor heater monitoring.
    (g)(9)(i) through (g)(9)(vi) [Reserved]. For guidance see Sec.  
86.010-18.
    (g)(9)(vii) Monitoring conditions for exhaust gas sensors.
    (A) The manufacturer must define the monitoring conditions for 
malfunctions identified in Sec.  86.010-18(g)(9)(ii)(A), 
(g)(9)(iii)(A), and (g)(9)(iv)(A) (i.e., sensor performance) and Table 
1 of paragraph (g) of this section in accordance with paragraphs (c) 
and (d) of this section. For purposes of tracking and reporting as 
required in Sec.  86.010-18(d) through (d)(1)(i), all monitors used to 
detect malfunctions identified in Sec.  86.010-18(g)(9)(ii)(A), 
(g)(9)(iii)(A), and(g)(9)(iv)(A) and Table 1 of paragraph (g) of this 
section must be tracked separately but reported as a single set of 
values as specified in Sec.  86.010-18(e)(1)(iii).
    (B) The manufacturer must define the monitoring conditions for 
malfunctions identified in Sec.  86.010-18(g)(9)(ii)(D), 
(g)(9)(iii)(D), and (g)(9)(iv)(D) (i.e., monitoring function) and Table 
1 of paragraph (g) of this section in accordance with paragraphs (c) 
and (d) of this section with the exception that monitoring must occur 
every time the monitoring conditions are met during the drive cycle 
rather than once per drive cycle as required in Sec.  86.010-18(c)(2).
    (g)(9)(vii)(C) and (g)(9)(vii)(D) [Reserved]. For guidance see 
Sec.  86.010-18.
    (g)(9)(viii) Monitoring conditions for exhaust gas sensor heaters.
    (A) The manufacturer must define monitoring conditions for 
malfunctions identified in Sec.  86.010-18(g)(9)(A) (i.e., sensor 
heater performance) and Table 1 of paragraph (g) of this section in 
accordance with paragraphs (c) and (d) of this section.
    (g)(9)(viii)(B) [Reserved]. For guidance see Sec.  86.010-18.
    (g)(9)(ix) Exhaust gas sensor and sensor heater MIL activation and 
DTC storage. The MIL must activate and DTCs must be stored according to 
the provisions of paragraph (b) of this section.
    (10) Variable valve timing (VVT) system monitoring.

[[Page 3332]]

    (g)(10)(i) and (g)(10)(vii) [Reserved]. For guidance see Sec.  
86.010-18.
    (g)(10)(iii) VVT system monitoring conditions. Manufacturers must 
define the monitoring conditions for VVT system malfunctions identified 
in Sec.  86.010-18(g)(10)(ii) and Table 1 of paragraph (g) of this 
section in accordance with paragraphs (c) and (d) of this section, with 
the exception that monitoring must occur every time the monitoring 
conditions are met during the drive cycle rather than once per drive 
cycle as required in Sec.  86.010-18(c)(2). For purposes of tracking 
and reporting as required in Sec.  86.010-18(d) through (d)(1)(i), all 
monitors used to detect malfunctions identified in Sec.  86.010-
18(g)(10)(ii) and Table 1 of paragraph (g) of this section must be 
tracked separately but reported as a single set of values as specified 
in Sec.  86.010-18(d)(1)(iii).
    (iv) VVT MIL activation and DTC storage. The MIL must activate and 
DTCs must be stored according to the provisions of paragraph (b) of 
this section.
    (h) [Reserved]. For guidance see Sec.  86.010-18.
    (i) OBD monitoring requirements for all engines.
    (1) Engine cooling system monitoring.
    (i)(1)(i) through (i)(1)(iii) [Reserved]. For guidance see Sec.  
86.010-18.
    (i)(1)(iv) Monitoring conditions for the thermostat.
    (A) The manufacturer must define the monitoring conditions for 
malfunctions identified in paragraph Sec.  86.010-18(i)(1)(ii)(A) and 
Table 1 of paragraph (g) of this section in accordance with paragraph 
(c) of this section. Additionally, except as provided for in Sec.  
86.010-18(i)(1)(iv)(B) and (i)(1)(iv)(C), monitoring for malfunctions 
identified in Sec.  86.010-18(i)(1)(ii)(A) and Table 1 of paragraph (g) 
of this section must be conducted once per drive cycle on every drive 
cycle in which the ECT sensor indicates, at engine start, a temperature 
lower than the temperature established as the malfunction criteria in 
Sec.  86.010-18(i)(1)(ii)(A) and Table 1 of paragraph (g) of this 
section.
    (i)(1)(iv)(B) and (i)(1)(iv)(C) [Reserved]. For guidance see Sec.  
86.010-18.
    (i)(1)(v) Monitoring conditions for the ECT sensor.
    (i)(1)(v)(A) [Reserved]. For guidance see Sec.  86.010-18.
    (i)(1)(v)(B) The manufacturer must define the monitoring conditions 
for malfunctions identified in Sec.  86.010-18(i)(1)(iii)(B) and Table 
1 of paragraph (g) of this section in accordance with paragraph (c) of 
this section. Additionally, except as provided for in Sec.  86.010-
18(i)(1)(v)(D), monitoring for malfunctions identified in Sec.  86.010-
18(i)(1)(iii)(B) and Table 1 of paragraph (g) of this section must be 
conducted once per drive cycle on every drive cycle in which the ECT 
sensor indicates a temperature lower than the closed-loop enable 
temperature at engine start (i.e., all engine start temperatures 
greater than the ECT sensor out-of-range low temperature and less than 
the closed-loop enable temperature).
    (C) The manufacturer must define the monitoring conditions for 
malfunctions identified in Sec.  86.010-18(i)(1)(iii)(C) and 
(i)(1)(iii)(D) and Table 1 of paragraph (g) of this section in 
accordance with paragraphs (c) and (d) of this section.
    (i)(1)(v)(D) and (i)(1)(v)(E) [Reserved]. For guidance see Sec.  
86.010-18.
    (i)(1)(vi) Engine cooling system MIL activation and DTC storage. 
The MIL must activate and DTCs must be stored according to the 
provisions of paragraph (b) of this section.
    (2) Crankcase ventilation (CV) system monitoring.
    (i)(2)(i) and (i)(2)(ii) [Reserved]. For guidance see Sec.  86.010-
18.
    (i)(2)(iii) Crankcase ventilation system monitoring conditions. The 
manufacturer must define the monitoring conditions for malfunctions 
identified in Sec.  86.010-18(i)(2)(ii) and Table 1 of paragraph (g) of 
this section in accordance with paragraphs (c) and (d) of this section.
    (iv) Crankcase ventilation system MIL activation and DTC storage. 
The MIL must activate and DTCs must be stored according to the 
provisions of paragraph (b) of this section. The stored DTC need not 
identify specifically the CV system (e.g., a DTC for idle speed control 
or fuel system monitoring can be stored) if the manufacturer can 
demonstrate that additional monitoring hardware would be necessary to 
make such an identification and provided the manufacturer's diagnostic 
and repair procedures for the detected malfunction include directions 
to check the integrity of the CV system.
    (3) Comprehensive component monitoring.
    (i) General. Except as provided for in paragraph (i)(4) of this 
section, the OBD system must detect a malfunction of any electronic 
engine component or system not otherwise described in paragraphs (g), 
(i)(1), and (i)(2) of this section and Sec.  86.010-18(h) that either 
provides input to (directly or indirectly, such components may include 
the crank angle sensor, knock sensor, throttle position sensor, cam 
position sensor, intake air temperature sensor, boost pressure sensor, 
manifold pressure sensor, mass air flow sensor, exhaust temperature 
sensor, exhaust pressure sensor, fuel pressure sensor, fuel composition 
sensor of a flexible fuel vehicle, etc.) or receives commands from 
(such components or systems may include the idle speed control system, 
glow plug system, variable length intake manifold runner systems, 
supercharger or turbocharger electronic components, heated fuel 
preparation systems, the wait-to-start lamp on diesel applications, the 
MIL, etc.) the onboard computer(s) and meets either of the criteria 
described in Sec.  86.010-18(i)(3)(i)(A) and/or (i)(3)(i)(B). Note 
that, for the purposes of this paragraph (i)(3), ``electronic engine 
component or system'' does not include components that are driven by 
the engine and are not related to the control of the fueling, air 
handling, or emissions of the engine (e.g., PTO components, air 
conditioning system components, and power steering components).
    (i)(3)(i)(A) through (i)(3)(iii) [Reserved]. For guidance see Sec.  
86.010-18.
    (i)(3)(iv) Monitoring conditions for input components.
    (i)(3)(iv)(A) [Reserved]. For guidance see Sec.  86.010-18.
    (i)(3)(iv)(B) For input component rationality checks (where 
applicable), the manufacturer must define the monitoring conditions for 
detecting malfunctions in accordance with paragraphs (c) and (d) of 
this section, with the exception that rationality checks must occur 
every time the monitoring conditions are met during the drive cycle 
rather than once per drive cycle as required in Sec.  86.010-18(c)(2).
    (v) Monitoring conditions for output components/systems.
    (i)(3)(v)(A) [Reserved]. For guidance see Sec.  86.010-18.
    (i)(3)(v)(B) For output component/system functional checks, the 
manufacturer must define the monitoring conditions for detecting 
malfunctions in accordance with paragraphs (c) and (d) of this section. 
Specifically for the idle control system, the manufacturer must define 
the monitoring conditions for detecting malfunctions in accordance with 
paragraphs (c) and (d) of this section, with the exception that 
functional checks must occur every time the monitoring conditions are 
met during the drive cycle rather than once per drive cycle as required 
in Sec.  86.010-18(c)(2).
    (vi) Comprehensive component MIL activation and DTC storage.
    (A) Except as provided for in Sec.  86.010-18(i)(3)(vi)(B) and 
(i)(3)(vi)(C), the MIL must activate and DTCs must be

[[Page 3333]]

stored according to the provisions of paragraph (b) of this section.
    (i)(3)(vi)(B) and (i)(3)(vi)(C) [Reserved]. For guidance see Sec.  
86.010-18.
    (i)(4) Other emission control system monitoring.
    (i) General. For other emission control systems that are either not 
addressed in Sec.  86.010-18(h) and paragraphs (g) and (i)(1) through 
(i)(3) of this section (e.g., hydrocarbon traps, homogeneous charge 
compression ignition control systems), or addressed in paragraph (i)(3) 
of this section but not corrected or compensated for by an adaptive 
control system (e.g., swirl control valves), the manufacturer must 
submit a plan for Administrator approval of the monitoring strategy, 
malfunction criteria, and monitoring conditions prior to introduction 
on a production engine. The plan must demonstrate the effectiveness of 
the monitoring strategy, the malfunction criteria used, the monitoring 
conditions required by the monitor, and, if applicable, the 
determination that the requirements of Sec.  86.010-18(i)(4)(ii) are 
satisfied.
    (i)(4)(ii) through (i)(5)(v) [Reserved]. For guidance see Sec.  
86.010-18.
    (i)(6) Feedback control system monitoring. If the engine is 
equipped with feedback control of any of the systems covered in 
paragraphs (g) and (i) of this section and Sec.  86.010-18(h), then the 
OBD system must detect as malfunctions the conditions specified in this 
paragraph (i)(6) for each of the individual feedback controls.
    (i)(6)(i) through (i)(6)(iv) [Reserved]. For guidance see Sec.  
86.010-18.
    (j) Production evaluation testing.
    (1) Verification of standardization requirements.
    (i) The manufacturer must perform testing to verify that production 
vehicles meet the requirements of paragraphs (k)(3) and (k)(4) of this 
section relevant to the proper communication of required emissions-
related messages to a SAE J1978/J1939 scan tool.
    (ii) Selection of test vehicles.
    (A) The manufacturer must perform this testing every model year on 
ten unique production vehicles (i.e., engine rating and chassis 
application combination) per engine family. If there are less than ten 
unique production vehicles for a certain engine family, the 
manufacturer must test each unique production vehicle in that engine 
family. The manufacturer must perform this testing within either three 
months of the start of engine production or one month of the start of 
vehicle production, whichever is later. The manufacturer may request 
approval to group multiple production vehicles together and test one 
representative vehicle per group. To do so, the software and hardware 
designed to comply with the standardization requirements of paragraph 
(k) of this section (e.g., communication protocol message timing, 
number of supported data stream parameters, engine and vehicle 
communication network architecture) in the representative vehicle must 
be identical to all others in the group and any differences in the 
production vehicles cannot be relevant with respect to meeting the 
criteria of paragraph (j)(1)(iv) of this section.
    (B) For 2016 and subsequent model years, the required number of 
vehicles to be tested shall be reduced to five per engine family 
provided zero vehicles fail the testing required by paragraph (j)(1) of 
this section for two consecutive years.
    (C) For 2019 and subsequent model years, the required number of 
vehicles to be tested shall be reduced to three per engine family 
provided zero vehicles fail the testing required by paragraph (j)(1) of 
this section for three consecutive years.
    (D) The requirement for submittal of data from one or more of the 
production vehicles shall be waived if data have been submitted 
previously for all of the production vehicles. The manufacturer may 
request approval to carry over data collected in previous model years. 
To do so, the software and hardware designed to comply with the 
standardization requirements of paragraph (k) of this section must be 
identical to the previous model year and there must not have been other 
hardware or software changes that affect compliance with the 
standardization requirements.
    (iii) Test equipment. For the testing required by paragraph (j)(1) 
of this section, the manufacturer shall use an off-board device to 
conduct the testing. The manufacturer must be able to show that the 
off-board device is able to verify that the vehicles tested using the 
device are able to perform all of the required functions in paragraph 
(j)(1)(iv) of this section with any other off-board device designed and 
built in accordance with the SAE J1978/J1939 generic scan tool 
specifications.
    (iv) Required testing. The testing must verify that communication 
can be established properly between all emission-related on-board 
computers and any SAE J1978/J1939 scan tool designed to adhere strictly 
to the communication protocols allowed in paragraph (k)(3) of this 
section. The testing must also verify that all emission-related 
information is communicated properly between all emission-related on-
board computers and any SAE J1978/J1939 scan tool in accordance with 
the requirements of paragraph (k) of this section and the applicable 
ISO and SAE specifications including specifications for physical layer, 
network layer, message structure, and message content. The testing must 
also verify that the onboard computer(s) can properly respond to any 
SAE J1978/J1939 scan tool request to clear emissions-related DTCs and 
reset the ready status in accordance with paragraph (k)(4)(ix) of this 
section. The testing must further verify that the following information 
can be properly communicated to any SAE J1978/J1939 scan tool:
    (A) The current ready status from all onboard computers required to 
support ready status in accordance with SAE J1978/J1939-73 and 
paragraph (k)(4)(i) of this section in the key-on, engine-off position 
and while the engine is running.
    (B) The MIL command status while a deactivated MIL is commanded and 
while an activated MIL is commanded in accordance with SAE J1979/J1939 
and paragraph (k)(4)(ii) of this section in the key-on, engine-off 
position and while the engine is running, and in accordance with SAE 
J1979/J1939 and Sec.  86.010-18(b)(1)(ii) during the MIL functional 
check and, if applicable, (k)(4)(i)(C) of this section during the MIL 
ready status check while the engine is off.
    (C) All data stream parameters required in paragraph (k)(4)(ii) of 
this section in accordance with SAE J1979/J1939 including, if 
applicable, the proper identification of each data stream parameter as 
supported in SAE J1979 (e.g., Mode/Service $01, PID $00).
    (D) The CAL ID, CVN, and VIN as required by paragraphs (k)(4)(vi), 
(k)(4)(vii), and (k)(4)(viii) of this section and in accordance with 
SAE J1979/J1939.
    (E) An emissions-related DTC (permanent, pending, MIL-on, previous-
MIL-on) in accordance with SAE J1979/J1939-73 (including the correct 
indication of the number of stored DTCs (e.g., Mode/Service $01, PID 
$01, Data A for SAE J1979)) and paragraph (k)(4)(iv) of this section.
    (v) Reporting of results. The manufacturer must submit to the 
Administrator the following, based on the results of the testing 
required by paragraph (j)(1)(iv) of this section:
    (A) If a variant meets all the requirements of paragraph (j)(1)(iv) 
of this section, a statement specifying that the variant passed all the 
tests. Upon request from the Administrator, the

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detailed results of any such testing may have to be submitted.
    (B) If any variant does not meet the requirements of paragraph 
(j)(1)(iv) of this section, a written report detailing the problem(s) 
identified and the manufacturer's proposed corrective action (if any) 
to remedy the problem(s). This report must be submitted within one 
month of testing the specific variant. The Administrator will consider 
the proposed remedy and, if in disagreement, will work with the 
manufacturer to propose an alternative remedy. Factors to be considered 
by the Administrator in considering the proposed remedy will include 
the severity of the problem(s), the ability of service technicians to 
access the required diagnostic information, the impact on equipment and 
tool manufacturers, and the amount of time prior to implementation of 
the proposed corrective action.
    (vi) Alternative testing protocols. Manufacturers may request 
approval to use other testing protocols. To do so, the manufacturer 
must demonstrate that the alternative testing methods and equipment 
will provide an equivalent level of verification of compliance with the 
standardization requirements as is required by paragraph (j)(1) of this 
section.
    (2) Verification of monitoring requirements.
    (j)(2)(i) through (j)(2)(ii)(C) [Reserved]. For guidance see Sec.  
86.010-18.
    (j)(2)(iii) Evaluation requirements.
    (A) The evaluation must demonstrate the ability of the OBD system 
on the selected test vehicle to detect a malfunction, activate the MIL, 
and, where applicable, store an appropriate DTC readable by a SAE 
J1978/J1939 scan tool when a malfunction is present and the monitoring 
conditions have been satisfied for each individual monitor required by 
this section.
    (j)(2)(iii)(B) through (j)(2)(iv) [Reserved]. For guidance see 
Sec.  86.010-18.
    (j)(3) Verification of in-use monitoring performance ratios.
    (j)(3)(i) through (j)(3)(iii) [Reserved]. For guidance see Sec.  
86.010-18.
    (j)(3)(iv) For each monitoring performance group, the data must 
include all of the in-use performance tracking data reported through 
SAE J1979/J1939 (i.e., all numerators, denominators, the general 
denominator, and the ignition cycle counter), the date the data were 
collected, the odometer reading, the VIN, and the calibration ID.
    (j)(3)(v) and (j)(3)(vi) [Reserved]. For guidance see Sec.  86.010-
18.
    (k) Standardization requirements.
    (k)(1) through (k)(1)(i)(B) [Reserved]. For guidance see Sec.  
86.010-18.
    (k)(1)(i)(C) SAE J1962 ``Diagnostic Connector--;Equivalent to ISO/
DIS 15031-3: December 14, 2001,'' April 2002.
    (k)(1)(i)(D) through (k)(1)(ii)(A) [Reserved]. For guidance see 
Sec.  86.010-18.
    (k)(2) Diagnostic connector. A standard data link connector 
conforming to SAE J1962 or SAE J1939-13 specifications (except as 
provided for in paragraph (k)(2)(iii) of this section) must be included 
in each vehicle.
    (i) The connector must be located in the driver's side foot-well 
region of the vehicle interior in the area bound by the driver's side 
of the vehicle and the driver's side edge of the center console (or the 
vehicle centerline if the vehicle does not have a center console) and 
at a location no higher than the bottom of the steering wheel when in 
the lowest adjustable position. The connector shall not be located on 
or in the center console (i.e., neither on the horizontal faces near 
the floor-mounted gear selector, parking brake lever, or cup-holders 
nor on the vertical faces near the car stereo, climate system, or 
navigation system controls). The location of the connector shall be 
capable of being easily identified and accessed (e.g., to connect an 
off-board tool). For vehicles equipped with a driver's side door, the 
connector must be identified and accessed easily by someone standing 
(or ``crouched'') on the ground outside the driver's side of the 
vehicle with the driver's side door open. The Administrator may approve 
an alternative location upon request from the manufacturer. In all 
cases, the installation position of the connector must be both 
identified and accessed easily by someone standing outside the vehicle 
and protected from accidental damage during normal vehicle use.
    (ii) If the connector is covered, the cover must be removable by 
hand without the use of any tools and be labeled ``OBD'' to aid 
technicians in identifying the location of the connector. Access to the 
diagnostic connector shall not require opening or the removal of any 
storage accessory (e.g., ashtray, coinbox). The label must clearly 
identify that the connector is located behind the cover and is 
consistent with language and/or symbols commonly used in the automobile 
and/or heavy truck industry.
    (iii) If the ISO 15765-4 communication protocol is used for the 
required OBD standardized functions, the connector must meet the ``Type 
A'' specifications of SAE J1962. Any pins in the connector that provide 
electrical power must be properly fused to protect the integrity and 
usefulness of the connector for diagnostic purposes and shall not 
exceed 20.0 Volts DC regardless of the nominal vehicle system or 
battery voltage (e.g., 12V, 24V, 42V).
    (iv) If the SAE J1939 protocol is used for the required OBD 
standardized functions, the connector must meet the specifications of 
SAE J1939-13. Any pins in the connector that provide electrical power 
must be properly fused to protect the integrity and usefulness of the 
connector for diagnostic purposes.
    (v) The manufacturer may equip engines/vehicles with additional 
diagnostic connectors for manufacturer-specific purposes (i.e., 
purposes other than the required OBD functions). However, if the 
additional connector conforms to the ``Type A'' specifications of SAE 
J1962 or the specifications of SAE J1939-13 and is located in the 
vehicle interior near the required connector as described in this 
paragraph (k)(2) of this section, the connector(s) must be labeled 
clearly to identify which connector is used to access the standardized 
OBD information required by paragraph (k) of this section.
    (3) Communications to a scan tool. All OBD control modules (e.g., 
engine, auxiliary emission control module) on a single vehicle must use 
the same protocol for communication of required emission-related 
messages from on-board to off-board network communications to a scan 
tool meeting SAE J1978 specifications or designed to communicate with 
an SAE J1939 network. Engine manufacturers shall not alter normal 
operation of the engine emission control system due to the presence of 
off-board test equipment accessing information required by this 
paragraph (k). The OBD system must use one of the following 
standardized protocols:
    (i) ISO 15765-4. All required emission-related messages using this 
protocol must use a 500 kbps baud rate.
    (ii) SAE J1939. This protocol may only be used on vehicles with 
diesel engines.
    (4) Required emission related functions. The following standardized 
functions must be implemented in accordance with the specifications in 
SAE J1979 or SAE J1939 to allow for access to the required information 
by a scan tool meeting SAE J1978 specifications or designed to 
communicate with an SAE J1939 network:
    (i) Ready status. In accordance with SAE J1979/J1939-73 
specifications, the OBD system must indicate ``complete'' or ``not 
complete'' for each of the installed monitored components and

[[Page 3335]]

systems identified in paragraphs (g), and (i)(3) of this section, and 
paragraph (h) with the exception of Sec.  86.010-18(h)(4). All 
components or systems identified in Sec.  86.010-18(h)(1) or (h)(2), or 
(i)(3) of this section that are monitored continuously must always 
indicate ``complete.'' Components or systems that are not subject to 
being monitored continuously must immediately indicate ``complete'' 
upon the respective monitor(s) being executed fully and determining 
that the component or system is not malfunctioning. A component or 
system must also indicate ``complete'' if, after the requisite number 
of decisions necessary for determining MIL status has been executed 
fully, the monitor indicates a malfunction of the component or system. 
The status for each of the monitored components or systems must 
indicate ``not complete'' whenever diagnostic memory has been cleared 
or erased by a means other than that allowed in paragraph (b) of this 
section. Normal vehicle shut down (i.e., key-off/engine-off) shall not 
cause the status to indicate ``not complete.''
    (k)(4)(i)(A) [Reserved]. For guidance see Sec.  86.010-18.
    (k)(4)(i)(B) For the evaporative system monitor, the ready status 
must be set in accordance with this paragraph (k)(4)(i) when both the 
functional check of the purge valve and, if applicable, the leak 
detection monitor of the hole size specified in Sec.  86.010-
18(h)(7)(ii)(B) indicate that they are complete.
    (C) If the manufacturer elects to indicate ready status through the 
MIL in the key-on/engine-off position as provided for in Sec.  86.010-
18(b)(1)(iii), the ready status must be indicated in the following 
manner: If the ready status for all monitored components or systems is 
``complete,'' the MIL shall remain continuously activated in the key-
on/engine-off position for at least 10-20 seconds. If the ready status 
for one or more of the monitored components or systems is ``not 
complete,'' after at least 5 seconds of operation in the key-on/engine-
off position with the MIL activated continuously, the MIL shall blink 
once per second for 5-10 seconds. The data stream value for MIL status 
as required in paragraph (k)(4)(ii) of this section must indicate 
``commanded off'' during this sequence unless the MIL has also been 
``commanded on'' for a detected malfunction.
    (ii) Data stream. The following signals must be made available on 
demand through the standardized data link connector in accordance with 
SAE J1979/J1939 specifications. The actual signal value must always be 
used instead of a limp home value.
    (k)(4)(ii)(A) through (k)(4)(ii)(C) [Reserved]. For guidance see 
Sec.  86.010-18.
    (k)(4)(iii) Freeze frame.
    (A) ``Freeze frame'' information required to be stored pursuant to 
Sec.  86.010-18(b)(2)(iv), (h)(1)(iv)(D), and (h)(2)(vi) must be made 
available on demand through the standardized data link connector in 
accordance with SAE J1979/J1939-73 specifications.
    (k)(4)(iii)(B) [Reserved]. For guidance see Sec.  86.010-18.
    (k)(4)(iii)(C) Only one frame of data is required to be recorded. 
The manufacturer may choose to store additional frames provided that at 
least the required frame can be read by a scan tool meeting SAE J1978 
specifications or designed to communicate with an SAE J1939 network.
    (iv) Diagnostic trouble codes.
    (A) For all monitored components and systems, any stored pending, 
MIL-on, and previous-MIL-on DTCs must be made available through the 
diagnostic connector in a standardized format in accordance with SAE 
J1939 or ISO 15765-4 specifications. Standardized DTCs conforming to 
the applicable standardized specifications must be employed.
    (k)(4)(iv)(B) and (k)(4)(iv)(C) [Reserved]. For guidance see Sec.  
86.010-18.
    (k)(4)(iv)(D) A pending or MIL-on DTC (as required in paragraphs 
(g) and (i) of this section and Sec.  86.010-18(h)) must be stored and 
available to an SAE J1978 or SAE J1939 scan tool within 10 seconds 
after a monitor has determined that a malfunction or potential 
malfunction has occurred. A permanent DTC must be stored and available 
to an SAE J1978 or SAE J1939 scan tool no later than the end of an 
ignition cycle in which the corresponding MIL-on DTC that caused MIL 
activation has been stored.
    (E) Pending DTCs for all components and systems (including those 
monitored continuously and non-continuously) must be made available 
through the diagnostic connector in accordance with the applicable 
standard's specifications. A manufacturer using alternative statistical 
protocols for MIL activation as allowed in Sec.  86.010-18(b)(2)(iii) 
must submit the details of their protocol for setting pending DTCs. The 
protocol must be, overall, equivalent to the requirements of this 
paragraph (k)(4)(iv)(E) and provide service technicians with a quick 
and accurate indication of a potential malfunction.
    (F) Permanent DTC for all components and systems must be made 
available through the diagnostic connector in a standardized format 
that distinguishes permanent DTCs from pending DTCs, MIL-on DTCs, and 
previous-MIL-on DTCs. A MIL-on DTC must be stored as a permanent DTC no 
later than the end of the ignition cycle and subsequently at all times 
that the MIL-on DTC is commanding the MIL on. Permanent DTCs must be 
stored in non-volatile random access memory (NVRAM) and shall not be 
erasable by any scan tool command or by disconnecting power to the on-
board computer. Permanent DTCs must be erasable if the engine control 
module is reprogrammed and the ready status described in paragraph 
(k)(4)(i) of this section for all monitored components and systems are 
set to ``not complete.'' The OBD system must have the ability to store 
a minimum of four current MIL-on DTCs as permanent DTCs in NVRAM. If 
the number of MIL-on DTCs currently commanding activation of the MIL 
exceeds the maximum number of permanent DTCs that can be stored, the 
OBD system must store the earliest detected MIL-on DTC as permanent 
DTC. If additional MIL-on DTCs are stored when the maximum number of 
permanent DTCs is already stored in NVRAM, the OBD system shall not 
replace any existing permanent DTC with the additional MIL-on DTCs.
    (v) Test results.
    (A) Except as provided for in Sec.  86.010-18(k)(4)(v)(G), for all 
monitored components and systems identified in paragraph (g) of this 
section and Sec.  86.010-18(h), results of the most recent monitoring 
of the components and systems and the test limits established for 
monitoring the respective components and systems must be stored and 
available through the data link in accordance with the standardized 
format specified in SAE J1979 (for engines using the ISO 15765-4 
protocol) or SAE J1939.
    (k)(4)(v)(B) [Reserved]. For guidance see Sec.  86.010-18.
    (k)(4)(v)(C) The test results must be standardized such that the 
name of the monitored component (e.g., catalyst bank 1) can be 
identified by a generic scan tool and the test results and limits can 
be scaled and reported by a generic scan tool with the appropriate 
engineering units.
    (k)(4)(v)(D) through (k)(4)(v)(G) [Reserved]. For guidance see 
Sec.  86.010-18.
    (k)(4)(vi) Software calibration identification (CAL ID). On all 
engines, a single software calibration identification number (CAL ID) 
for each monitor or emission critical control unit(s) must be made 
available through the standardized data link connector in accordance 
with the SAE J1979/J1939

[[Page 3336]]

specifications. A unique CAL ID must be used for every emission-related 
calibration and/or software set having at least one bit of different 
data from any other emission-related calibration and/or software set. 
Control units coded with multiple emission or diagnostic calibrations 
and/or software sets must indicate a unique CAL ID for each variant in 
a manner that enables an off-board device to determine which variant is 
being used by the vehicle. Control units that use a strategy that will 
result in MIL activation if the incorrect variant is used (e.g., 
control units that contain variants for manual and automatic 
transmissions but will activate the MIL if the selected variant does 
not match the type of transmission mated to the engine) are not 
required to use unique CAL IDs.
    (vii) Software calibration verification number (CVN).
    (A) All engines must use an algorithm to calculate a single 
calibration verification number (CVN) that verifies the on-board 
computer software integrity for each monitor or emission critical 
control unit that is electronically reprogrammable. The CVN must be 
made available through the standardized data link connector in 
accordance with the SAE J1979/J1939 specifications. The CVN must 
indicate whether the emission-related software and/or calibration data 
are valid and applicable for the given vehicle and CAL ID.
    (k)(4)(vii)(B) [Reserved]. For guidance see Sec.  86.010-18.
    (k)(4)(vii)(C) The CVN must be calculated at least once per drive 
cycle and stored until the CVN is subsequently updated. Except for 
immediately after a reprogramming event or a non-volatile memory clear 
or for the first 30 seconds of engine operation after a volatile memory 
clear or battery disconnect, the stored value must be made available 
through the data link connector to a generic scan tool in accordance 
with SAE J1979/J1939 specifications. The stored CVN value shall not be 
erased when DTC memory is erased by a generic scan tool in accordance 
with SAE J1979/J1939 specifications or during normal vehicle shut down 
(i.e., key-off/engine-off).
    (D) The CVN and CAL ID combination information must be available 
for all engines/vehicles in a standardized electronic format that 
allows for off-board verification that the CVN is valid and appropriate 
for a specific vehicle and CAL ID.
    (viii) Vehicle identification number (VIN).
    (A) All vehicles must have the vehicle identification number (VIN) 
available in a standardized format through the standardized data link 
connector in accordance with SAE J1979/J1939 specifications. Only one 
electronic control unit per vehicle may report the VIN to an SAE J1978/
J1939 scan tool.
    (k)(4)(viii)(B) [Reserved]. For guidance see Sec.  86.010-18.
    (k)(4)(ix) Erasure of diagnostic information.
    (A) For purposes of this paragraph (k)(4)(ix), ``emission-related 
diagnostic information'' includes all of the following: ready status as 
required by paragraph (k)(4)(i) of this section; data stream 
information as required by paragraph (k)(4)(ii) of this section 
including the number of stored MIL-on DTCs, distance traveled while MIL 
activated, number of warm-up cycles since DTC memory last erased, and 
distance traveled since DTC memory last erased; freeze frame 
information as required by paragraph (k)(4)(iii) of this section; 
pending, MIL-on, and previous-MIL-on DTCs as required by paragraph 
(k)(4)(iv) of this section; and, test results as required by paragraph 
(k)(4)(v) of this section.
    (k)(4)(ix)(B) [Reserved]. For guidance see Sec.  86.010-18.
    (k)(5) In-use performance ratio tracking requirements.
    (i) For each monitor required in paragraphs (g) and (i) of this 
section and Sec.  86.010-18(h) to separately report an in-use 
performance ratio, manufacturers must implement software algorithms to 
report a numerator and denominator in the standardized format specified 
in this paragraph (k)(5) in accordance with the SAE J1979/J1939 
specifications.
    (ii) For the numerator, denominator, general denominator, and 
ignition cycle counters required by Sec.  86.010-18(e), the following 
numerical value specifications apply:
    (A) Each number shall have a minimum value of zero and a maximum 
value of 65,535 with a resolution of one.
    (B) Each number shall be reset to zero only when a non-volatile 
random access memory (NVRAM) reset occurs (e.g., reprogramming event) 
or, if the numbers are stored in keep-alive memory (KAM), when KAM is 
lost due to an interruption in electrical power to the control unit 
(e.g., battery disconnect). Numbers shall not be reset to zero under 
any other circumstances including when a scan tool command to clear 
DTCs or reset KAM is received.
    (C) To avoid overflow problems, if either the numerator or 
denominator for a specific component reaches the maximum value of 
65,535 2, both numbers shall be divided by two before 
either is incremented again.
    (D) To avoid overflow problems, if the ignition cycle counter 
reaches the maximum value of 65,535 2, the ignition cycle 
counter shall rollover and increment to zero on the next ignition 
cycle.
    (E) To avoid overflow problems, if the general denominator reaches 
the maximum value of 65,535 2, the general denominator 
shall rollover and increment to zero on the next drive cycle that meets 
the general denominator definition.
    (F) If a vehicle is not equipped with a component (e.g., oxygen 
sensor bank 2, secondary air system), the corresponding numerator and 
denominator for that specific component shall always be reported as 
zero.
    (iii) For the ratio required by Sec.  86.010-18(e), the following 
numerical value specifications apply:
    (A) The ratio shall have a minimum value of zero and a maximum 
value of 7.99527 with a resolution of 0.000122.
    (B) The ratio for a specific component shall be considered to be 
zero whenever the corresponding numerator is equal to zero and the 
corresponding denominator is not zero.
    (C) The ratio for a specific component shall be considered to be 
the maximum value of 7.99527 if the corresponding denominator is zero 
or if the actual value of the numerator divided by the denominator 
exceeds the maximum value of 7.99527.
    (6) Engine run time tracking requirements.
    (i) For all gasoline and diesel engines, the manufacturer must 
implement software algorithms to track and report individually in a 
standardized format the amount of time the engine has been operated in 
the following conditions:
    (A) Total engine run time.
    (B) Total idle run time (with ``idle'' defined as accelerator pedal 
released by the driver, vehicle speed less than or equal to one mile 
per hour, engine speed greater than or equal to 50 to 150 rpm below the 
normal, warmed-up idle speed (as determined in the drive position for 
vehicles equipped with an automatic transmission), and power take-off 
not active).
    (C) Total run time with power take off active.
    (ii) For each counter specified in paragraph (k)(6)(i) of this 
section, the following numerical value specifications apply:
    (A) Each number shall be a four-byte value with a minimum value of 
zero, a resolution of one second per bit, and an accuracy of  ten seconds per drive cycle.

[[Page 3337]]

    (B) Each number shall be reset to zero only when a non-volatile 
memory reset occurs (e.g., reprogramming event). Numbers shall not be 
reset to zero under any other circumstances including when a scan tool 
(generic or enhanced) command to clear fault codes or reset KAM is 
received.
    (C) To avoid overflow problems, if any of the individual counters 
reach the maximum value, all counters shall be divided by two before 
any are incremented again.
    (D) The counters shall be made available to a generic scan tool in 
accordance with the SAE J1979/J1939 specifications and may be rescaled 
when transmitted, if required by the SAE specifications, from a 
resolution of one second per bit to no more than three minutes per bit.
    (l) Monitoring system demonstration requirements for certification.
    (1) General.
    (l)(1)(i) through (l)(1)(iii) [Reserved]. For guidance see Sec.  
86.010-18.
    (l)(2) Selection of test engines.
    (l)(2)(i) [Reserved]. For guidance see Sec.  86.010-18.
    (l)(2)(ii) A manufacturer certifying one to five engine families in 
a given model year must provide emissions test data for a single test 
engine from one engine rating. A manufacturer certifying six to ten 
engine families in a given model year must provide emissions test data 
for a single test engine from two different engine ratings. A 
manufacturer certifying eleven or more engine families in a given model 
year must provide emissions test data for a single test engine from 
three different engine ratings. A manufacturer may forego submittal of 
test data for one or more of these test engines if data have been 
submitted previously for all of the engine ratings and/or if all 
requirements for certification carry-over from one model year to the 
next are satisfied.
    (iii) For a given model year, a manufacturer may elect to provide 
emissions data for test engines from more engine ratings than required 
by paragraph (l)(2)(ii) of this section. For each additional engine 
rating tested in that given model year, the number of engine ratings 
required for testing in one future model year will be reduced by one.
    (iv) For the test engine, the manufacturer must use an engine aged 
for a minimum of 125 hours fitted with exhaust aftertreatment emission 
controls aged to be representative of useful life aging. The 
manufacturer is required to submit a description of the accelerated 
aging process and/or supporting data. The process and/or data must 
demonstrate assurance that deterioration of the exhaust aftertreatment 
emission controls is stabilized sufficiently such that it represents 
emission control performance at the end of the useful life.
    (3) Required testing. Except as otherwise described in this 
paragraph (l)(3) of this section, the manufacturer must perform single 
malfunction testing based on the applicable test with the components/
systems set at their malfunction criteria limits as determined by the 
manufacturer for meeting the emissions thresholds required in 
paragraphs (g) and (i) of this section and Sec.  86.010-18(h).
    (i) Required testing for diesel-fueled/compression ignition 
engines.
    (l)(3)(i)(A) [Reserved]. For guidance see Sec.  86.010-18.
    (l)(3)(i)(B) Engine misfire. The manufacturer must perform a test 
at the malfunction limit established by the manufacturer for the 
monitoring required by paragraph (g)(2)(ii)(B) of this section.
    (l)(3)(i)(C) through (l)(3)(i)(K) [Reserved]. For guidance see 
Sec.  86.010-18.
    (l)(3)(ii) Required testing for gasoline-fueled/spark-ignition 
engines.
    (l)(3)(ii)(A) through (l)(3)(ii)(I) [Reserved]. For guidance see 
Sec.  86.010-18.
    (l)(3)(iii) Required testing for all engines.
    (l)(3)(iii)(A) and (l)(3)(iii)(B) [Reserved]. For guidance see 
Sec.  86.010-18.
    (l)(3)(iv) [Reserved]. For guidance see Sec.  86.010-18.
    (l)(4) Testing protocol.
    (l)(4)(i) [Reserved]. For guidance see Sec.  86.010-18.
    (l)(4)(ii) Test sequence.
    (l)(4)(ii)(A) through (l)(4)(ii)(C) [Reserved]. For guidance see 
Sec.  86.010-18.
    (l)(4)(iii) A manufacturer required to test more than one test 
engine according to paragraph (l)(2)(ii) of this section may use 
internal calibration sign-off test procedures (e.g., forced cool downs, 
less frequently calibrated emission analyzers) instead of official test 
procedures to obtain the emission test data required by this paragraph 
(l) of this section for all but one of the required test engines. The 
manufacturer may elect this option if the data from the alternative 
test procedure are representative of official emissions test results. A 
manufacturer using this option is still responsible for meeting the 
malfunction criteria specified in paragraphs (g) and (i) of this 
section and Sec.  86.010-18(h) if and when emissions tests are 
performed in accordance with official test procedures.
    (l)(4)(iv) [Reserved]. For guidance see Sec.  86.010-18.
    (l)(5) Evaluation protocol.
    (l)(5)(i) [Reserved]. For guidance see Sec.  86.010-18.
    (l)(5)(ii) If the MIL activates prior to emissions exceeding the 
applicable malfunction criteria limits specified in paragraphs (g) and 
(i) of this section and Sec.  86.010-18(h), no further demonstration is 
required. With respect to the misfire monitor demonstration test, if 
the manufacturer has elected to use the minimum misfire malfunction 
criteria of one percent as allowed in paragraphs (g)(2)(ii)(B) of this 
section and Sec.  86.010-18(h)(2)(ii)(B), no further demonstration is 
required provided the MIL activates with engine misfire occurring at 
the malfunction criteria limit.
    (l)(5)(iii) through (l)(5)(iv) [Reserved]. For guidance see Sec.  
86.010-18.
    (l)(6) Confirmatory testing.
    (i) The Administrator may perform confirmatory testing to verify 
the emission test data submitted by the manufacturer as required by 
paragraph (l) of this section comply with its requirements and the 
malfunction criteria set forth in paragraphs (g) and (i) of this 
section and Sec.  86.010-18(h). Such confirmatory testing is limited to 
the test engine(s) required by paragraph (l)(2) of this section.
    (l)(6)(ii) through (l)(7) [Reserved]. For guidance see Sec.  
86.010-18.
    (m) Certification documentation requirements.
    (m)(1) through (m)(2)(iv) [Reserved]. For guidance see Sec.  
86.010-18.
    (m)(2)(v) Emissions test data, a description of the testing 
sequence (e.g., the number and types of preconditioning cycles), 
approximate time (in seconds) of MIL activation during the test, 
diagnostic trouble code(s) and freeze frame information stored at the 
time of detection, corresponding test results (e.g. SAE J1979 Mode/
Service $06, SAE J1939 Diagnostic Message 8 (DM8)) stored during the 
test, and a description of the modified or deteriorated components used 
for malfunction simulation with respect to the demonstration tests 
specified in paragraph (l) of this section. The freeze frame data are 
not required for engines subject to paragraph (o)(3) of this section.
    (m)(2)(vi) through (m)(2)(x) [Reserved]. For guidance see Sec.  
86.010-18.
    (m)(2)(xi) A written identification of the communication protocol 
utilized by each engine for communication with a SAE J1978/J1939 scan 
tool.
    (xii) A pictorial representation or written description of the 
diagnostic

[[Page 3338]]

connector location including any covers or labels.
    (m)(2)(xiii) [Reserved]. For guidance see Sec.  86.010-18.
    (m)(2)(xiv) Build specifications provided to engine purchasers or 
chassis manufacturers detailing all specifications or limitations 
imposed on the engine purchaser relevant to OBD requirements or 
emissions compliance (e.g., allowable MIL locations, connector location 
specifications, cooling system heat rejection rates). A description of 
the method or copies of agreements used to ensure engine purchasers or 
chassis manufacturers will comply with the OBD and emissions relevant 
build specifications (e.g., signed agreements, required audit/
evaluation procedures).
    (m)(2)(xv) [Reserved]. For guidance see Sec.  86.010-18.
    (n) [Reserved]. For guidance see Sec.  86.010-18.
    (o) Implementation schedule. Except as provided for in paragraph 
(o)(4) of this section, the requirements of this section must be met 
according to the following provisions:
    (1) OBD groups. The manufacturer shall define one or more OBD 
groups to cover all engine ratings in all engine families. The 
manufacturer must submit a grouping plan for Administrator review and 
approval detailing the OBD groups and the engine families and engine 
ratings within each group for a given model year.
    (2) Full OBD.
    (i) For all engine ratings subject to Sec.  86.010-18, the 
manufacturer must implement an OBD system meeting the requirements of 
this section.
    (ii) On one engine rating within each of the manufacturer's OBD 
groups, the manufacturer must implement an OBD system meeting the 
requirements of this section. These ``full OBD'' ratings will be known 
as the ``OBD parent'' ratings. The OBD parent rating for each OBD group 
must be chosen as the rating having the highest weighted projected U.S. 
sales within the OBD group, with U.S. sales being weighted by the 
useful life of the engine rating.
    (3) Extrapolated OBD. For all other engine ratings within each OBD 
group, the manufacturer must implement an OBD system meeting the 
requirements of this section except that the OBD system is not required 
to detect a malfunction prior to exceeding the emission thresholds 
shown in Table 1 of paragraph (g) of this section and Table 2 of Sec.  
86.010-18(h). These extrapolated OBD engines will be known as the ``OBD 
child'' ratings. On these OBD child ratings, rather than detecting a 
malfunction prior to exceeding the emission thresholds, the 
manufacturer must submit a plan for Administrator review and approval 
that details the engineering evaluation the manufacturer will use to 
establish the malfunction criteria for the OBD child ratings. The plan 
must demonstrate both the use of good engineering judgment in 
establishing the malfunction criteria, and robust detection of 
malfunctions, including consideration of differences of base engine, 
calibration, emission control components, and emission control 
strategies.
    (4) Engines certified as alternative fueled engines shall meet the 
following requirements:
    (i) To the extent feasible, those specified in paragraph (i)(3) of 
this section.
    (ii) Monitor the NOX aftertreatment system on engines so 
equipped. A malfunction must be detected if:
    (A) The NOX aftertreatment system has no detectable 
amount of NOX aftertreatment capability (i.e., 
NOX catalyst conversion or NOX adsorption).
    (B) The NOX aftertreatment substrate is completely 
destroyed, removed, or missing.
    (C) The NOX aftertreatment assembly is replaced with a 
straight pipe.
    (p) In-use compliance standards. For monitors required to indicate 
a malfunction before emissions exceed a certain emission threshold 
(e.g., 2 times any of the applicable standards):
    (1) On the full OBD ratings as defined in paragraph (o)(2) of this 
section, separate in-use emissions thresholds shall apply. These 
thresholds are determined by doubling the applicable thresholds as 
shown in Table 1 of paragraph (g) of this section and Table 2 of Sec.  
86.010-18(h). The resultant thresholds apply only in-use and do not 
apply for certification or selective enforcement auditing.
    (2) The extrapolated OBD ratings as defined in paragraph (o)(3) of 
this section shall not be evaluated against emissions levels for 
purposes of OBD compliance in-use.
    (3) Only the test cycle and standard determined and identified by 
the manufacturer at the time of certification in accordance with Sec.  
86.010-18(f) as the most stringent shall be used for the purpose of 
determining OBD system noncompliance in-use.
    (4) For monitors subject to meeting the minimum in-use monitor 
performance ratio of 0.100 in paragraph (d)(1)(ii) of this section, the 
OBD system shall not be considered noncompliant unless a representative 
sample indicates the in-use ratio is below 0.050.
    (5) An OBD system shall not be considered noncompliant solely due 
to a failure or deterioration mode of a monitored component or system 
that could not have been reasonably foreseen to occur by the 
manufacturer.
    13. Section 86.013-30 is added to Subpart A to read as follows:


Sec.  86.013-30  Certification.

    Section 86.013-30 includes text that specifies requirements that 
differ from Sec.  86.010-30. Where a paragraph in Sec.  86.010-30 is 
identical and applicable to Sec.  86.013-30, this may be indicated by 
specifying the corresponding paragraph and the statement ``[Reserved]. 
For guidance see Sec.  86.010-30.''
    (a) introductory text through (f)(1)(i) [Reserved]. For guidance 
see Sec.  86.010-30.
    (f)(1)(ii) Diesel.
    (A) If monitored for emissions performance--a reduction catalyst is 
replaced with a deteriorated or defective catalyst, or an electronic 
simulation of such, resulting in exhaust NOX emissions 
exceeding the applicable NOX FEL+0.3 g/bhp-hr. Also if 
monitored for emissions performance--an oxidation catalyst is replaced 
with a deteriorated or defective catalyst, or an electronic simulation 
of such, resulting in exhaust NMHC emissions exceeding 2 times the 
applicable NMHC standard.
    (B) If monitored for performance--a particulate trap is replaced 
with a deteriorated or defective trap, or an electronic simulation of 
such, resulting in either exhaust PM emissions exceeding the applicable 
FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is higher; or, exhaust 
NMHC emissions exceeding 2 times the applicable NMHC standard. Also, if 
monitored for performance--a particulate trap is replaced with a 
catastrophically failed trap or a simulation of such.
    (f)(2) [Reserved]. For guidance see Sec.  86.004-30.
    (f)(3)(i) Oxygen sensors and air-fuel ratio sensors downstream of 
aftertreatment devices.
    (f)(3)(i)(A) [Reserved]. For guidance see Sec.  86.007-30.
    (f)(3)(i)(B) Diesel. If so equipped, any oxygen sensor or air-fuel 
ratio sensor located downstream of aftertreatment devices is replaced 
with a deteriorated or defective sensor, or an electronic simulation of 
such, resulting in exhaust emissions exceeding any of the following 
levels: The applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, 
whichever is higher; or, the applicable NOX FEL+0.3 g/bhp-
hr; or, 2 times the applicable NMHC standard.
    (ii) Oxygen sensors and air-fuel ratio sensors upstream of 
aftertreatment devices.
    (f)(3)(ii)(A) [Reserved]. For guidance see Sec.  86.007-30.

[[Page 3339]]

    (f)(3)(ii)(B) Diesel. If so equipped, any oxygen sensor or air-fuel 
ratio sensor located upstream of aftertreatment devices is replaced 
with a deteriorated or defective sensor, or an electronic simulation of 
such, resulting in exhaust emissions exceeding any of the following 
levels: The applicable PM FEL+0.02 g/bhp-hr or 0.03 g/bhp-hr PM, 
whichever is higher; or, the applicable NOX FEL+0.3 g/bhp-
hr; or, 2 times the applicable NMHC standard; or, 2 times the 
applicable CO standard.
    (iii) NOX sensors.
    (f)(3)(iii)(A) [Reserved]. For guidance see Sec.  86.007-30.
    (f)(3)(iii)(B) Diesel. If so equipped, any NOX sensor is 
replaced with a deteriorated or defective sensor, or an electronic 
simulation of such, resulting in exhaust emissions exceeding any of the 
following levels: The applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr 
PM, whichever is higher; or, the applicable NOX FEL+0.3 g/
bhp-hr.
    (f)(4) [Reserved]. For guidance see Sec.  86.010-30.
    (f)(5)(i) [Reserved]. For guidance see Sec.  86.007-30.
    (f)(5)(ii) Diesel. A malfunction condition is induced in any 
emission-related engine system or component, including but not 
necessarily limited to, the exhaust gas recirculation (EGR) system, if 
equipped, and the fuel control system, singularly resulting in exhaust 
emissions exceeding any of the following levels: The applicable PM 
FEL+0.02 g/bhp-hr or 0.03 g/bhp-hr PM, whichever is higher; or, the 
applicable NOX FEL+0.3 g/bhp-hr; or, 2 times the applicable 
NMHC standard; or, 2 times the applicable CO standard.
    (f)(6) [Reserved]. For guidance see Sec.  86.010-30.
    14. Section 86.016-18 is added to Subpart A to read as follows:


Sec.  86.016-18  On-board Diagnostics for engines used in applications 
greater than 14,000 pounds GVWR.

    Section 86.016-18 includes text that specifies requirements that 
differ from Sec.  86.013-18. Where a paragraph in Sec.  86.013-18 is 
identical and applicable to Sec.  86.016-18, this may be indicated by 
specifying the corresponding paragraph and the statement ``[Reserved]. 
For guidance see Sec.  86.013-18.''
    (a) through (n) [Reserved]. For guidance see Sec.  86.013-18.
    (o) Implementation schedule. Except as provided for in paragraph 
(o)(3) of this section, the requirements of this section must be met 
according to the following provisions:
    (1) OBD groups. The manufacturer shall define one or more OBD 
groups to cover all engine ratings in all engine families. The 
manufacturer must submit a grouping plan for Administrator review and 
approval detailing the OBD groups and the engine families and engine 
ratings within each group for a given model year.
    (2) Full OBD. The manufacturer must implement an OBD system meeting 
the requirements of this section on all engine ratings in all engine 
families.
    (3) Engines certified as alternative fueled engines shall meet the 
following requirements:
    (i) To the extent feasible, those specified in Sec.  86.013-
18(i)(3).
    (ii) Monitor the NOX aftertreatment system on engines so 
equipped. A malfunction must be detected if:
    (A) The NOX aftertreatment system has no detectable 
amount of NOX aftertreatment capability (i.e., 
NOX catalyst conversion or NOX adsorption).
    (B) The NOX aftertreatment substrate is completely 
destroyed, removed, or missing.
    (C) The NOX aftertreatment assembly is replaced with a 
straight pipe.
    (p) In-use compliance standards. For monitors required to indicate 
a malfunction before emissions exceed a certain emission threshold 
(e.g., 2 times any of the applicable standards):
    (1) On the engine ratings tested according to Sec.  86.013-
18(l)(2)(ii), the certification emissions thresholds shall apply in-
use.
    (2) On the manufacturer's remaining engine ratings, separate in-use 
emissions thresholds shall apply. These thresholds are determined by 
doubling the applicable thresholds as shown in Table 1 of Sec.  86.013-
18(g) and Table 2 of Sec.  86.010-18(h). The resultant thresholds apply 
only in-use and do not apply for certification or selective enforcement 
auditing.
    (3) An OBD system shall not be considered noncompliant solely due 
to a failure or deterioration mode of a monitored component or system 
that could not have been reasonably foreseen to occur by the 
manufacturer.
    15. Section 86.019-18 is added to subpart A to read as follows:


Sec.  86.019-18  On-board diagnostics for engines used in applications 
greater than 14,000 pounds GVWR.

    Section 86.019-18 includes text that specifies requirements that 
differ from Sec. Sec.  86.013-18 and 86.016-18. Where a paragraph in 
Sec.  86.013-18 is identical and applicable to Sec.  86.019-18, this 
may be indicated by specifying the corresponding paragraph and the 
statement ``[Reserved]. For guidance see Sec.  86.013-18.''
    (a) through (k)(6) [Reserved]. For guidance see Sec.  86.013-18.
    (k)(7) For 2019 and subsequent model year alternative-fueled 
engines derived from a diesel-cycle engine, a manufacturer may meet the 
standardization requirements of Sec.  86.013-18(k) that are applicable 
to diesel engines rather than the requirements applicable to gasoline 
engines.
    (l) through (n) [Reserved]. For guidance see Sec.  86.013-18.
    (o) Implementation schedule. The manufacturer must implement an OBD 
system meeting the requirements of this section on all engines.
    (p) In-use compliance. An OBD system shall not be considered 
noncompliant solely due to a failure or deterioration mode of a 
monitored component or system that could not have been reasonably 
foreseen to occur by the manufacturer.
    16. Section 86.1806-07 is added to Subpart S to read as follows:


Sec.  86.1806-07  On-board diagnostics for vehicles less than or equal 
to 14,000 pounds GVWR.

    Section 86.1806-07 includes text that specifies requirements that 
differ from Sec.  86.1806-05. Where a paragraph in Sec.  86.1806-05 is 
identical and applicable to Sec.  86.1806-07, this may be indicated by 
specifying the corresponding paragraph and the statement ``[Reserved]. 
For guidance see Sec.  86.1806-05.''
    (a) through (a)(2) [Reserved]. For guidance see Sec.  86.1806-05.
    (a)(3) An OBD system demonstrated to fully meet the requirements in 
Sec.  86.007-17 may be used to meet the requirements of this section, 
provided that such an OBD system also incorporates appropriate 
transmission diagnostics as may be required under this section, and 
provided that the Administrator finds that a manufacturer's decision to 
use the flexibility in this paragraph (a)(3) is based on good 
engineering judgement.
    (b) through (h) [Reserved]. For guidance see Sec.  86.1806-05.
    (i) Deficiencies and alternative fueled vehicles. Upon application 
by the manufacturer, the Administrator may accept an OBD system as 
compliant even though specific requirements are not fully met. Such 
compliances without meeting specific requirements, or deficiencies, 
will be granted only if compliance would be infeasible or unreasonable 
considering such factors as, but not limited to: technical feasibility 
of the given monitor and lead time and production cycles including 
phase-in or phase-out of vehicle designs and programmed upgrades of 
computers. Unmet requirements should

[[Page 3340]]

not be carried over from the previous model year except where 
unreasonable hardware or software modifications would be necessary to 
correct the deficiency, and the manufacturer has demonstrated an 
acceptable level of effort toward compliance as determined by the 
Administrator. Furthermore, EPA will not accept any deficiency requests 
that include the complete lack of a major diagnostic monitor (``major'' 
diagnostic monitors being those for exhaust aftertreatment devices, 
oxygen sensor, air-fuel ratio sensor, NOX sensor, engine 
misfire, evaporative leaks, and diesel EGR, if equipped), with the 
possible exception of the special provisions for alternative fueled 
engines. For alternative fueled vehicles (e.g., natural gas, liquefied 
petroleum gas, methanol, ethanol), manufacturers may request the 
Administrator to waive specific monitoring requirements of this section 
for which monitoring may not be reliable with respect to the use of the 
alternative fuel. At a minimum, alternative fuel engines must be 
equipped with an OBD system meeting OBD requirements to the extent 
feasible as approved by the Administrator.
    (j) California OBDII compliance option. For light-duty vehicles, 
light-duty trucks, and heavy-duty vehicles weighing 14,000 pounds GVWR 
or less, demonstration of compliance with California OBD II 
requirements (Title 13 California Code of Regulations Sec.  1968.2 (13 
CCR 1968.2)), as modified and released on August 11, 2006, shall 
satisfy the requirements of this section, except that compliance with 
13 CCR 1968.2(e)(4.2.2)(C), pertaining to 0.02-inch evaporative leak 
detection, and 13 CCR 1968.2(d)(1.4), pertaining to tampering 
protection, are not required to satisfy the requirements of this 
section. Also, the deficiency provisions of 13 CCR 1968.2(k) do not 
apply. The deficiency provisions of paragraph (i) of this section and 
the evaporative leak detection requirement of Sec.  86.1806-05(b)(4) 
apply to manufacturers selecting this paragraph for demonstrating 
compliance. In addition, demonstration of compliance with 13 CCR 
1968.2(e)(15.2.1)(C), to the extent it applies to the verification of 
proper alignment between the camshaft and crankshaft, applies only to 
vehicles equipped with variable valve timing.
    (k) through (m) [Reserved]. For guidance see Sec.  86.1806-05.
    (n) For diesel complete heavy-duty vehicles, in lieu of the 
malfunction descriptions of Sec.  86.1806-05(b), the malfunction 
descriptions of this paragraph (n) shall apply. The OBD system must 
detect and identify malfunctions in all monitored emission-related 
powertrain systems or components according to the following malfunction 
definitions as measured and calculated in accordance with test 
procedures set forth in subpart B of this part (chassis-based test 
procedures), excluding those test procedures defined as 
``Supplemental'' test procedures in Sec.  86.004-2 and codified in 
Sec. Sec.  86.158, 86.159, and 86.160.
    (1) Catalysts and particulate traps.
    (i) If equipped, catalyst deterioration or malfunction before it 
results in exhaust emissions exceeding 3 times the applicable 
NOX standard. This requirement applies only to reduction 
catalysts; monitoring of oxidation catalysts is not required. This 
monitoring need not be done if the manufacturer can demonstrate that 
deterioration or malfunction of the system will not result in 
exceedance of the threshold.
    (ii) If equipped with a particulate trap, catastrophic failure of 
the device must be detected. Any particulate trap whose complete 
failure results in exhaust emissions exceeding 1.5 times the applicable 
standard or FEL for NOX or PM must be monitored for such 
catastrophic failure. This monitoring need not be done if the 
manufacturer can demonstrate that a catastrophic failure of the system 
will not result in exceedance of the threshold.
    (2) Engine misfire. Lack of cylinder combustion must be detected.
    (3)(i) Oxygen sensors and air-fuel ratio sensors downstream of 
aftertreatment devices. If equipped, sensor deterioration or 
malfunction resulting in exhaust emissions exceeding any of the 
following levels: 4 times the applicable PM standard; or, 3 times the 
applicable NOX standard; or, 2.5 times the applicable NMHC 
standard.
    (ii) Oxygen sensors and air-fuel ratio sensors upstream of 
aftertreatment devices. If equipped, sensor deterioration or 
malfunction resulting in exhaust emissions exceeding any of the 
following levels: 4 times the applicable PM standard; or, 3 times the 
applicable NOX standard; or, 2.5 times the applicable NMHC 
standard; or, 2.5 times the applicable CO standard.
    (iii) NOX sensors. If equipped, sensor deterioration or 
malfunction resulting in exhaust emissions exceeding any of the 
following levels: 5 times the applicable PM standard; or, 4 times the 
applicable NOX standard.
    (4) [Reserved.]
    (5) Other emission control systems and components. Any 
deterioration or malfunction occurring in an engine system or component 
directly intended to control emissions, including but not necessarily 
limited to, the exhaust gas recirculation (EGR) system, if equipped, 
and the fuel control system, singularly resulting in exhaust emissions 
exceeding any of the following levels: 4 times the applicable PM 
standard; or, 3 times the applicable NOX standard; or, 2.5 
times the applicable NMHC standard; or, 2.5 times the applicable CO 
standard. A functional check, as described in paragraph (n)(6) of this 
section, may satisfy the requirements of this paragraph (n)(5) provided 
the manufacturer can demonstrate that a malfunction would not cause 
emissions to exceed the applicable levels. This demonstration is 
subject to Administrator approval. For engines equipped with crankcase 
ventilation (CV), monitoring of the CV system is not necessary provided 
the manufacturer can demonstrate to the Administrator's satisfaction 
that the CV system is unlikely to fail.
    (6) Other emission-related powertrain components. Any other 
deterioration or malfunction occurring in an electronic emission-
related powertrain system or component not otherwise described in 
paragraphs (n)(1) through (n)(5) of this section that either provides 
input to or receives commands from the on-board computer and has a 
measurable impact on emissions; monitoring of components required by 
this paragraph (n)(6) must be satisfied by employing electrical circuit 
continuity checks and rationality checks for computer input components 
(input values within manufacturer specified ranges based on other 
available operating parameters), and functionality checks for computer 
output components (proper functional response to computer commands) 
except that the Administrator may waive such a rationality or 
functionality check where the manufacturer has demonstrated 
infeasibility. Malfunctions are defined as a failure of the system or 
component to meet the electrical circuit continuity checks or the 
rationality or functionality checks.
    (7) Performance of OBD functions. Any sensor or other component 
deterioration or malfunction which renders that sensor or component 
incapable of performing its function as part of the OBD system must be 
detected and identified on engines so equipped.
    (o) For diesel complete heavy-duty vehicles, in lieu of the 
certification provisions of Sec.  86.1806-05(k), the certificate 
provisions of this paragraph (o) shall apply. For test groups required 
to have an OBD system, certification will not be granted if, for any 
test vehicle approved by the Administrator in consultation with the 
manufacturer, the malfunction indicator light does not

[[Page 3341]]

illuminate under any of the following circumstances, unless the 
manufacturer can demonstrate that any identified OBD problems 
discovered during the Administrator's evaluation will be corrected on 
production vehicles.
    (1)(i) If monitored for emissions performance--a catalyst is 
replaced with a deteriorated or defective catalyst, or an electronic 
simulation of such, resulting in exhaust emissions exceeding 3 times 
the applicable NOX standard. This requirement applies only 
to reduction catalysts.
    (ii) If monitored for performance--a particulate trap is replaced 
with a trap that has catastrophically failed, or an electronic 
simulation of such.
    (2) An engine misfire condition is induced and is not detected.
    (3)(i) If so equipped, any oxygen sensor or air-fuel ratio sensor 
located downstream of aftertreatment devices is replaced with a 
deteriorated or defective sensor, or an electronic simulation of such, 
resulting in exhaust emissions exceeding any of the following levels: 4 
times the applicable PM standard; or, 3 times the applicable 
NOX standard; or, 2.5 times the applicable NMHC standard.
    (ii) If so equipped, any oxygen sensor or air-fuel ratio sensor 
located upstream of aftertreatment devices is replaced with a 
deteriorated or defective sensor, or an electronic simulation of such, 
resulting in exhaust emissions exceeding any of the following levels: 4 
times the applicable PM standard; or, 3 times the applicable 
NOX standard; or, 2.5 times the applicable NMHC standard; 
or, 2.5 times the applicable CO standard.
    (iii) If so equipped, any NOX sensor is replaced with a 
deteriorated or defective sensor, or an electronic simulation of such, 
resulting in exhaust emissions exceeding any of the following levels: 5 
times the applicable PM standard; or, 4 times the applicable 
NOX standard.
    (4) [Reserved.]
    (5) A malfunction condition is induced in any emission-related 
engine system or component, including but not necessarily limited to, 
the exhaust gas recirculation (EGR) system, if equipped, and the fuel 
control system, singularly resulting in exhaust emissions exceeding any 
of the following levels: 4 times the applicable PM standard; or, 3 
times the applicable NOX standard; or, 2.5 times the 
applicable NMHC standard; or, 2.5 times the applicable CO standard.
    (6) A malfunction condition is induced in an electronic emission-
related powertrain system or component not otherwise described in this 
paragraph (o) that either provides input to or receives commands from 
the on-board computer resulting in a measurable impact on emissions.
    17. Section 86.1806-10 is added to Subpart S to read as follows:


Sec.  86.1806-10  On-board diagnostics for vehicles less than or equal 
to 14,000 pounds GVWR.

    Section 86.1806-10 includes text that specifies requirements that 
differ from Sec.  86.1806-05 and Sec.  86.1806-07. Where a paragraph in 
Sec.  86.1806-05 or Sec.  86.1806-07 is identical and applicable to 
Sec.  86.1806-10, this may be indicated by specifying the corresponding 
paragraph and the statement ``[Reserved]. For guidance see Sec.  
86.1806-05.'' or ``[Reserved]. For guidance see Sec.  86.1806-07.''
    (a) General.
    (1) All light-duty vehicles, light-duty trucks and complete heavy-
duty vehicles weighing 14,000 pounds GVWR or less (including MDPVs) 
must be equipped with an onboard diagnostic (OBD) system capable of 
monitoring all emission-related powertrain systems or components during 
the applicable useful life of the vehicle. All systems and components 
required to be monitored by these regulations must be evaluated 
periodically, but no less frequently than once per applicable 
certification test cycle as defined in paragraphs (a) and (d) of 
Appendix I of this part, or similar trip as approved by the 
Administrator.
    (2) [Reserved.]
    (3) An OBD system demonstrated to fully meet the requirements in 
Sec.  86.010-17 may be used to meet the requirements of this section, 
provided that such an OBD system also incorporates appropriate 
transmission diagnostics as may be required under this section, and 
provided that the Administrator finds that a manufacturer's decision to 
use the flexibility in this paragraph (a)(3) is based on good 
engineering judgement.
    (b) through (m) [Reserved]. For guidance see Sec.  86.1806-07.
    (n) For diesel complete heavy-duty vehicles, in lieu of the 
malfunction descriptions of Sec.  86.1806-05(b), the malfunction 
descriptions of this paragraph (n) shall apply. The OBD system must 
detect and identify malfunctions in all monitored emission-related 
powertrain systems or components according to the following malfunction 
definitions as measured and calculated in accordance with test 
procedures set forth in subpart B of this part (chassis-based test 
procedures), excluding those test procedures defined as 
``Supplemental'' test procedures in Sec.  86.004-2 and codified in 
Sec. Sec.  86.158, 86.159, and 86.160.
    (1) Catalysts and particulate traps.
    (i) If equipped, reduction catalyst deterioration or malfunction 
before it results in exhaust NOX emissions exceeding the 
applicable NOX standard+0.3 g/mi. If equipped, oxidation 
catalyst deterioration or malfunction before it results in exhaust NMHC 
emissions exceeding 2.5 times the applicable NMHC standard. These 
catalyst monitoring requirements need not be done if the manufacturer 
can demonstrate that deterioration or malfunction of the system will 
not result in exceedance of the threshold.
    (ii) If equipped, diesel particulate trap deterioration or 
malfunction before it results in exhaust emissions exceeding any of the 
following levels: 4 times the applicable PM standard; or, exhaust NMHC 
emissions exceeding 2.5 times the applicable NMHC standard. 
Catastrophic failure of the particulate trap must also be detected. In 
addition, the absence of the particulate trap or the trapping substrate 
must be detected.
    (2) Engine misfire. Lack of cylinder combustion must be detected.
    (3)(i) Oxygen sensors and air-fuel ratio sensors downstream of 
aftertreatment devices. If equipped, sensor deterioration or 
malfunction resulting in exhaust emissions exceeding any of the 
following levels: 4 times the applicable PM standard; or, the 
applicable NOX standard+0.3 g/mi; or, 2.5 times the 
applicable NMHC standard.
    (ii) Oxygen sensors and air-fuel ratio sensors upstream of 
aftertreatment devices. If equipped, sensor deterioration or 
malfunction resulting in exhaust emissions exceeding any of the 
following levels: The applicable PM standard+0.02 g/mi; or, the 
applicable NOX standard+0.3 g/mi; or, 2.5 times the 
applicable NMHC standard; or, 2.5 times the applicable CO standard.
    (iii) NOX sensors. If equipped, sensor deterioration or 
malfunction resulting in exhaust emissions exceeding any of the 
following levels: 4 times the applicable PM standard; or, the 
applicable NOX standard+0.3 g/mi.
    (4) [Reserved.]
    (5) Other emission control systems and components. Any 
deterioration or malfunction occurring in an engine system or component 
directly intended to control emissions, including but not necessarily 
limited to, the exhaust gas recirculation (EGR) system, if equipped, 
and the fuel control system, singularly resulting in exhaust emissions 
exceeding any of the following levels: 4 times the applicable PM 
standard; or, the applicable NOX standard+0.3 g/mi;

[[Page 3342]]

or, 2.5 times the applicable NMHC standard; or, 2.5 times the 
applicable CO standard. A functional check, as described in paragraph 
(n)(6) of this section, may satisfy the requirements of this paragraph 
(n)(5) provided the manufacturer can demonstrate that a malfunction 
would not cause emissions to exceed the applicable levels. This 
demonstration is subject to Administrator approval. For engines 
equipped with crankcase ventilation (CV), monitoring of the CV system 
is not necessary provided the manufacturer can demonstrate to the 
Administrator's satisfaction that the CV system is unlikely to fail.
    (6) Other emission-related powertrain components. Any other 
deterioration or malfunction occurring in an electronic emission-
related powertrain system or component not otherwise described in 
paragraphs (n)(1) through (n)(5) of this section that either provides 
input to or receives commands from the on-board computer and has a 
measurable impact on emissions; monitoring of components required by 
this paragraph (n)(6) must be satisfied by employing electrical circuit 
continuity checks and rationality checks for computer input components 
(input values within manufacturer specified ranges based on other 
available operating parameters), and functionality checks for computer 
output components (proper functional response to computer commands) 
except that the Administrator may waive such a rationality or 
functionality check where the manufacturer has demonstrated 
infeasibility. Malfunctions are defined as a failure of the system or 
component to meet the electrical circuit continuity checks or the 
rationality or functionality checks.
    (7) Performance of OBD functions. Any sensor or other component 
deterioration or malfunction which renders that sensor or component 
incapable of performing its function as part of the OBD system must be 
detected and identified on engines so equipped.
    (o) For diesel complete heavy-duty vehicles, in lieu of the 
certification provisions of Sec.  86.1806-5(k), the certification 
provisions of this paragraph (o) shall apply. For test groups required 
to have an OBD system, certification will not be granted if, for any 
test vehicle approved by the Administrator in consultation with the 
manufacturer, the malfunction indicator light does not illuminate under 
any of the following circumstances, unless the manufacturer can 
demonstrate that any identified OBD problems discovered during the 
Administrator's evaluation will be corrected on production vehicles.
    (1)(i) If monitored for emissions performance--a reduction catalyst 
is replaced with a deteriorated or defective catalyst, or an electronic 
simulation of such, resulting in exhaust NOX emissions 
exceeding the applicable NOX standard+0.3 g/mi. Also if 
monitored for emissions performance--an oxidation catalyst is replaced 
with a deteriorated or defective catalyst, or an electronic simulation 
of such, resulting in exhaust NMHC emissions exceeding 2.5 times the 
applicable NMHC standard.
    (ii) If monitored for performance--a particulate trap is replaced 
with a deteriorated or defective trap, or an electronic simulation of 
such, resulting in exhaust PM emissions exceeding 4 times the 
applicable PM standard or exhaust NMHC emissions exceeding 2.5 times 
the applicable NMHC standard. Also, if monitored for performance--a 
particulate trap is replaced with a catastrophically failed trap or a 
simulation of such.
    (2) An engine misfire condition is induced and is not detected.
    (3)(i) If so equipped, any oxygen sensor or air-fuel ratio sensor 
located downstream of aftertreatment devices is replaced with a 
deteriorated or defective sensor, or an electronic simulation of such, 
resulting in exhaust emissions exceeding any of the following levels: 4 
times the applicable PM standard; or, the applicable NOX 
standard+0.3 g/mi; or, 2.5 times the applicable NMHC standard.
    (ii) If so equipped, any oxygen sensor or air-fuel ratio sensor 
located upstream of aftertreatment devices is replaced with a 
deteriorated or defective sensor, or an electronic simulation of such, 
resulting in exhaust emissions exceeding any of the following levels: 
The applicable PM standard+0.02 g/mi; or, the applicable NOX 
standard+0.3 g/mi; or, 2.5 times the applicable NMHC standard; or, 2.5 
times the applicable CO standard.
    (iii) If so equipped, any NOX sensor is replaced with a 
deteriorated or defective sensor, or an electronic simulation of such, 
resulting in exhaust emissions exceeding any of the following levels: 4 
times the applicable PM standard; or, the applicable NOX 
standard+0.3 g/mi.
    (4) [Reserved.]
    (5) A malfunction condition is induced in any emission-related 
engine system or component, including but not necessarily limited to, 
the exhaust gas recirculation (EGR) system, if equipped, and the fuel 
control system, singularly resulting in exhaust emissions exceeding any 
of the following levels: 4 times the applicable PM standard; or, the 
applicable NOX standard+0.3 g/mi; or, 2.5 times the 
applicable NMHC standard; or, 2.5 times the applicable CO standard.
    (6) A malfunction condition is induced in an electronic emission-
related powertrain system or component not otherwise described in this 
paragraph (o) that either provides input to or receives commands from 
the on-board computer resulting in a measurable impact on emissions.
    18. Section 86.1806-13 is added to Subpart S to read as follows:


Sec.  86.1806-13  On-board diagnostics for vehicles less than or equal 
to 14,000 pounds GVWR.

    Section 86.1806-13 includes text that specifies requirements that 
differ from Sec.  86.1806-05, Sec.  86.1806-07 and Sec.  86.1806-10. 
Where a paragraph in Sec.  86.1806-05 or Sec.  86.1806-07 or Sec.  
86.1806-10 is identical and applicable to Sec.  86.1806-13 this may be 
indicated by specifying the corresponding paragraph and the statement 
``[Reserved]. For guidance see Sec.  86.1806-05.'' or ``[Reserved]. For 
guidance see Sec.  86.1806-07.'' or ``[Reserved]. For guidance see 
Sec.  86.1806-10.''
    (a)(1) [Reserved]. For guidance see Sec.  86.1806-10.
    (a)(2) [Reserved.]
    (3) An OBD system demonstrated to fully meet the requirements in 
Sec.  86.013-17 may be used to meet the requirements of this section, 
provided that such an OBD system also incorporates appropriate 
transmission diagnostics as may be required under this section, and 
provided that the Administrator finds that a manufacturer's decision to 
use the flexibility in this paragraph (a)(3) is based on good 
engineering judgement.
    (b) through (m) [Reserved]. For guidance see Sec.  86.1806-07.
    (n) For diesel complete heavy-duty vehicles, in lieu of the 
malfunction descriptions of Sec.  86.1806-05(b), the malfunction 
descriptions of this paragraph (n) shall apply. The OBD system must 
detect and identify malfunctions in all monitored emission-related 
powertrain systems or components according to the following malfunction 
definitions as measured and calculated in accordance with test 
procedures set forth in subpart B of this part (chassis-based test 
procedures), excluding those test procedures defined as 
``Supplemental'' test procedures in Sec.  86.004-2 and codified in 
Sec. Sec.  86.158, 86.159, and 86.160.
    (1) Catalysts and particulate traps.
    (i) If equipped, reduction catalyst deterioration or malfunction 
before it results in exhaust NOX emissions exceeding the 
applicable NOX

[[Page 3343]]

standard+0.3 g/mi. If equipped, oxidation catalyst deterioration or 
malfunction before it results in exhaust NMHC emissions exceeding 2 
times the applicable NMHC standard. These catalyst monitoring 
requirements need not be done if the manufacturer can demonstrate that 
deterioration or malfunction of the system will not result in 
exceedance of the threshold.
    (ii) If equipped, diesel particulate trap deterioration or 
malfunction before it results in exhaust emissions exceeding any of the 
following levels: the applicable PM standard+0.04 g/mi; or, exhaust 
NMHC emissions exceeding 2 times the applicable NMHC standard. 
Catastrophic failure of the particulate trap must also be detected. In 
addition, the absence of the particulate trap or the trapping substrate 
must be detected.
    (2) Engine misfire. Lack of cylinder combustion must be detected.
    (3)(i) Oxygen sensors and air-fuel ratio sensors downstream of 
aftertreatment devices. If equipped, sensor deterioration or 
malfunction resulting in exhaust emissions exceeding any of the 
following levels: the applicable PM standard+0.04 g/mi; or, the 
applicable NOX standard+0.3 g/mi; or, 2 times the applicable 
NMHC standard.
    (ii) Oxygen sensors and air-fuel ratio sensors upstream of 
aftertreatment devices. If equipped, sensor deterioration or 
malfunction resulting in exhaust emissions exceeding any of the 
following levels: the applicable PM standard+0.02 g/mi; or, the 
applicable NOX standard+0.3 g/mi; or, 2 times the applicable 
NMHC standard; or, 2 times the applicable CO standard.
    (iii) NOX sensors. If equipped, sensor deterioration or 
malfunction resulting in exhaust emissions exceeding any of the 
following levels: the applicable PM standard+0.04 g/mi; or, the 
applicable NOX standard+0.3 g/mi.
    (4) [Reserved.]
    (5) Other emission control systems and components. Any 
deterioration or malfunction occurring in an engine system or component 
directly intended to control emissions, including but not necessarily 
limited to, the exhaust gas recirculation (EGR) system, if equipped, 
and the fuel control system, singularly resulting in exhaust emissions 
exceeding any of the following levels: the applicable PM standard+0.02 
g/mi; or, the applicable NOX standard+0.3 g/mi; or, 2 times 
the applicable NMHC standard; or, 2 times the applicable CO standard. A 
functional check, as described in paragraph (n)(6) of this section, may 
satisfy the requirements of this paragraph (n)(5) provided the 
manufacturer can demonstrate that a malfunction would not cause 
emissions to exceed the applicable levels. This demonstration is 
subject to Administrator approval. For engines equipped with crankcase 
ventilation (CV), monitoring of the CV system is not necessary provided 
the manufacturer can demonstrate to the Administrator's satisfaction 
that the CV system is unlikely to fail.
    (6) Other emission-related powertrain components. Any other 
deterioration or malfunction occurring in an electronic emission-
related powertrain system or component not otherwise described in 
paragraphs (n)(1) through (n)(5) of this section that either provides 
input to or receives commands from the on-board computer and has a 
measurable impact on emissions; monitoring of components required by 
this paragraph (n)(6) must be satisfied by employing electrical circuit 
continuity checks and rationality checks for computer input components 
(input values within manufacturer specified ranges based on other 
available operating parameters), and functionality checks for computer 
output components (proper functional response to computer commands) 
except that the Administrator may waive such a rationality or 
functionality check where the manufacturer has demonstrated 
infeasibility. Malfunctions are defined as a failure of the system or 
component to meet the electrical circuit continuity checks or the 
rationality or functionality checks.
    (7) Performance of OBD functions. Any sensor or other component 
deterioration or malfunction which renders that sensor or component 
incapable of performing its function as part of the OBD system must be 
detected and identified on engines so equipped.
    (o) For diesel complete heavy-duty vehicles, in lieu of the 
certification provisions of paragraph (k) of this section, the 
certification provisions of this paragraph (o) shall apply. For test 
groups required to have an OBD system, certification will not be 
granted if, for any test vehicle approved by the Administrator in 
consultation with the manufacturer, the malfunction indicator light 
does not illuminate under any of the following circumstances, unless 
the manufacturer can demonstrate that any identified OBD problems 
discovered during the Administrator's evaluation will be corrected on 
production vehicles.
    (1)(i) If monitored for emissions performance--a reduction catalyst 
is replaced with a deteriorated or defective catalyst, or an electronic 
simulation of such, resulting in exhaust NOX emissions 
exceeding the applicable NOX standard+0.3 g/mi. Also if 
monitored for emissions performance--an oxidation catalyst is replaced 
with a deteriorated or defective catalyst, or an electronic simulation 
of such, resulting in exhaust NMHC emissions exceeding 2 times the 
applicable NMHC standard.
    (ii) If monitored for performance--a particulate trap is replaced 
with a deteriorated or defective trap, or an electronic simulation of 
such, resulting in exhaust PM emissions exceeding the applicable 
standard+0.04 g/mi or exhaust NMHC emissions exceeding 2 times the 
applicable NMHC standard. Also, if monitored for performance--a 
particulate trap is replaced with a catastrophically failed trap or a 
simulation of such.
    (2) An engine misfire condition is induced and is not detected.
    (3)(i) If so equipped, any oxygen sensor or air-fuel ratio sensor 
located downstream of aftertreatment devices is replaced with a 
deteriorated or defective sensor, or an electronic simulation of such, 
resulting in exhaust emissions exceeding any of the following levels: 
the applicable PM standard+0.04 g/mi; or, the applicable NOX 
standard+0.3 g/mi; or, 2 times the applicable NMHC standard.
    (ii) If so equipped, any oxygen sensor or air-fuel ratio sensor 
located upstream of aftertreatment devices is replaced with a 
deteriorated or defective sensor, or an electronic simulation of such, 
resulting in exhaust emissions exceeding any of the following levels: 
the applicable PM standard+0.02 g/mi; or, the applicable NOX 
standard+0.3 g/mi; or, 2 times the applicable NMHC standard; or, 2 
times the applicable CO standard.
    (iii) If so equipped, any NOX sensor is replaced with a 
deteriorated or defective sensor, or an electronic simulation of such, 
resulting in exhaust emissions exceeding any of the following levels: 
the applicable PM standard+0.04 g/mi; or, the applicable NOX 
standard+0.3 g/mi.
    (4) [Reserved.]
    (5) A malfunction condition is induced in any emission-related 
engine system or component, including but not necessarily limited to, 
the exhaust gas recirculation (EGR) system, if equipped, and the fuel 
control system, singularly resulting in exhaust emissions exceeding any 
of the following levels: the applicable PM standard+0.02 g/mi; or, the 
applicable NOX standard+0.3 g/mi; or, 2 times the applicable 
NMHC standard; or, 2 times the applicable CO standard.
    (6) A malfunction condition is induced in an electronic emission-
related powertrain system or component not otherwise described in this

[[Page 3344]]

paragraph (o) that either provides input to or receives commands from 
the on-board computer resulting in a measurable impact on emissions.

[FR Doc. 07-110 Filed 1-23-07; 8:45 am]
BILLING CODE 6560-50-P