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2005 News Releases


EPA Vehicle Diagnostic Systems Requirements and Evaporative Emissions Rules Updated and Clarified

Release Date: 12/02/2005
Contact Information:

Contact: John Millett, 202-564-4355 /

(12/2/05) EPA finalized a pair of rules designed to clarify and update its existing vehicle On-Board Diagnostic (OBD) program and amend provisions of its evaporative emission regulations. The OBD clarifications will allow manufacturers of passenger vehicles, trucks and heavy-duty engines to choose one OBD system to satisfy federal and California state requirements. OBD systems detect excess emissions and potential vehicle repair needs and provide drivers with an early warning light when these situations arise.

In a separate rulemaking, EPA finalized amendments to provisions of its evaporative emissions regulations. EPA's evaporative emissions regulations detail the testing process motor vehicle manufacturers must follow to obtain emissions certification as required in the Clean Air Act. An evaporative emissions test detects the amount of hydrocarbon pollution that results when liquid fuel molecules evaporate and escape into the atmosphere. The final amendments will streamline the evaporative emissions test procedures for cars, trucks, pickups, minivans, SUVs and larger trucks up to 14,000 pounds, and will harmonize EPA and California's evaporative emissions test procedures. In addition, the amendments will allow vehicle manufacturers and EPA to use more advanced testing equipment to test four-wheel and all-wheel drive vehicles. Finally, this action revises Vehicle Emission Control Information label requirements so that label information is up to date and more useful to all interested parties, such as EPA, manufacturers and repair technicians.

For more information on EPA's OBD program, visit: or

For more information on EPA's evaporative emissions program, visit: