EPA Finalizes 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 Applications
Under 14,000 Pounds
The U.S. Environmental Protection Agency (EPA) is promulgating
regulations that will require the emission control systems of large
highway diesel and gasoline trucks to 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. In addition
to these requirements, the Agency is requiring manufacturers to 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. This rule also makes changes to
certain existing OBD requirements for smaller highway heavy-duty
diesel trucks.
Background
• On January 18, 2001, EPA established a comprehensive national control
program—the Clean Diesel Trucks and Buses program—to regulate the
heavy-duty vehicle and its fuel as a single system. (66 FR 5002) As part of
United States
Environmental Protection
Agency
Office of Transportation and Air Quality
EPA420-F-08-032
November 2008
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this program, new emission standards began to take effect in model year 2007 and are
being phased-in through 2010, and 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 program also reduces the level of sulfur in highway diesel fuel
by 97 percent. The emissions reductions associated with this program are estimated to
result in over $70 billion in benefits through reduced hospitalizations and lost work days.
The OBD requirements will help to ensure that these benefits are realized.
On February 19, 1993, EPA published a final rule requiring manufacturers of light-duty
applications to install 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.
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 regula-
tions, in part, required each Original Equipment Manufacturer (OEM) to list all of its
emission-related service and repair information on a Web site and note how to obtain
that information and at what cost. The intent being 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. 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, EPA published a final rule requiring OBD systems on heavy-duty
vehicles and engines up to 14,000 pounds gross vehicle weight rating (GVWR) (65
FR 59896). In that rule, EPA expressed its intention to develop in a future rule OBD
requirements for vehicles and engines used in vehicles over 14,000 pounds. EPA again
expressed this same intention in its Clean Diesel Trucks and Busses final rule (66 FR
5002) which established new heavy-duty highway emissions standards for 2007 and later
model year engines (i.e., the "2007 Highway Rule").
In June of 2003, EPA published a final rule extending service information availability
requirements to heavy-duty vehicles and engines weighing up to 14,000 pounds GVWR.
EPA did not extend these requirements to engines above 14,000 pounds GVWR, deciding
to wait until such engines were subject to OBD requirements.
Overview of the OBD Final Rule
In 2005, the California Air Resources Board put into place heavy-duty onboard diagnostic
(HDOBD) requirements. More recently, we granted a waiver from federal preemption to the
State of California that allows them to implement the HDOBD program (73 FR 52042). Given
the nature of the heavy-duty trucking industry in the United States and the importance of the
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free and open movement of goods across state borders, we believe that a consistent nation-
wide HDOBD program is a desirable outcome. We have worked closely with California on our
proposal and with both California and industry stakeholders on this final rule, in an effort to
develop a consistent set of HDOBD requirements. As a result, EPA's new HDOBD program is
consistent with the California program in almost all important aspects. We believe that, while
minor differences exist in the requirements we are promulgating and the California require-
ments, we will end up with OBD systems that will be compliant with both our federal program
and the California program. Promulgating and implementing this final rule is an important step
in our efforts working with the California Air Resources Board to develop a consistent national
program.
The rule requires 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. In addition, when a malfunction occurs, diagnostic information must be stored in the
engine's computer to assist in diagnosis and repair of the malfunction. Also, manufacturers are
required to 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.
All of these requirements will help to ensure that the significant benefits of EPA's 2007 and 2010
heavy-duty highway standards will be realized in-use. Specifically:
• For 2010 and later model year heavy-duty diesel and gasoline engines used in high-
way applications over 14,000 pounds, we are requiring that all major emissions control
systems be monitored and malfunctions be detected prior to emissions exceeding a set of
emissions thresholds. Most notably, we are requiring that the aftertreatment devices—
e.g., the diesel particulate filters and oxides of nitrogen (NOx) reducing catalysts—that
will be used on highway diesel engines to comply with the 2010 emissions standards will
be monitored and their failure will be detected and noted to the driver. We are also requiring
that all emission-related electronic sensors and actuators be monitored for proper opera-
tion.
• For these highway applications over 14,000 pounds, we are requiring that one engine
family per manufacturer be certified to the OBD requirements in the 2010 through 2012
model years. Beginning in 2013, all highway engines for all manufacturers would have to
be certified to the OBD requirements. This phase-in is designed to spread over a number of
years the development effort required of industry and to provide industry with a learning
period prior to implementing the complex OBD requirements on 100 percent of their
highway product line.
• For applications over 14,000 pounds, the service information availability requirements
would apply for those engines certified to the OBD requirements.
• For 2010 and later model year highway heavy-duty diesel applications under 14,000
pounds, we are promulgating a new emissions threshold for monitoring of the diesel
particulate filter. The existing requirement for these applications is to detect a catastrophic
failure of the device. We believe that a more stringent requirement is appropriate and
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feasible. The emission threshold is consistent, both in stringency and in timing, with the
particulate matter (PM) thresholds for over 14,000 pound applications.
For 2007 and later model year diesel highway heavy-duty applications under 14,000
pounds, we are promulgating a change to the existing emission thresholds for NOx emissions.
The existing thresholds, typically 1.5 times the applicable NOx standard, were established
when the engine's NOx standard was much higher than today's very low level. We
believe these OBD thresholds are not technologically feasible in the context of EPA's
very stringent NOx emission standards, and this change addresses that issue.
Health and Environmental Effects
In our 2007 heavy-duty highway rule, we estimated that the new 2007 highway standards will
result in substantial benefits to the public health and welfare through significant annual reductions in
emissions of NOx, PM, nonmethane hydrocarbons (NMHC), carbon monoxide, sulfur dioxide,
and air toxics. These emission reductions will prevent 8,300 premature deaths, more than 9,500
hospitalizations, and 1.5 million work days lost. The OBD requirements will help to ensure that
these projected benefits will be realized.
As a result of the 2007 highway program, each new truck and bus will be more than 90 percent
cleaner than current models. We project a 2.6 million ton reduction of NOx emissions in 2030
when the current heavy-duty vehicle fleet is completely replaced with newer heavy-duty vehi-
cles that comply with the 2007 program's emission standards. By 2030, the program will reduce
annual emissions of NMHC by 115,000 tons and PM by 109,000 tons.
Ozone causes a range of health problems related to breathing, including chest pain, cough-
ing, and shortness of breath. PM is deposited deep in the lungs and causes premature death,
increased emergency room visits, and increased respiratory symptoms and disease. With both
ozone and PM, children and the elderly are most at risk. In addition, ozone, NOx, and PM
adversely affect the environment in various ways, including crop damage, acid rain, and visibility
impairment.
We have not estimated new emissions reductions associated with this OBD rule. We consider
OBD to be a critical element to an overall emissions control program. As such, OBD require-
ments and their associated benefits were assumed in our estimated emissions reductions associ-
ated with the 2007 highway rule.
Cost Effects
We project that the OBD requirements will result in an increased hardware cost of roughly $60
per diesel engine and $70 per gasoline engine used in applications over 14,000 pounds. We proj-
ect that the new requirements for diesel heavy-duty applications under 14,000 pounds will have
no increased hardware cost since these engines and vehicles have complied with OBD require-
ments since 2004.
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Public Participation Opportunities
You can access the rule and related documents on EPA's Office of Transportation and Air
Quality (OTAQ) Web site at:
www.epa.gov/obd
For More Information
For additional information specific to OBD, please contact:
Todd Sherwood
U.S. Environmental Protection Agency
Office of Transportation and Air Quality
Assessment and Standards Division
2000 Traverwood Drive
Ann Arbor, MI 48105
734-214-4405
E-mail sherwood.todd@epa.gov.
For additional information specific to service information availability, please contact:
Holly Pugliese
U.S. Environmental Protection Agency
Office of Transportation and Air Quality
Compliance and Innovative Strategies Division
Ann Arbor, MI48105
734-214-4288
E-mail pugliese.holly@epa.gov.
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