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EPA Vehicle On-Board Diagnosis Clean Air Act Enforcement

EPA enforces the requirements governing motor vehicles under Title II of the Clean Air Act (Act), and regulations promulgated at 40 CFR 86.094-17 and -21. Since Model Year 1996, passenger vehicle manufacturers have been required to install On-Board Diagnostic (OBD) systems to alert drivers and technicians of malfunctions which can cause substantial excess emissions. The OBD system lights a dashboard light in the vehicle to advise the driver of the need for service. The OBD system also stores a code to provide service technicians information about the flaw which was detected.

Manufacturers are required by statute and regulation to secure from EPA a Certificate of Conformity with applicable emission standards for each motor vehicle sold. As part of its application for a Certificate of Conformity manufacturers must describe each vehicle's emission control system, including the OBD systems. This allows EPA to assess the adequacy of the emission control system. In the case of the OBD system, the adequacy is tied closely to the accuracy and the frequency of operation of the diagnostic checks. In recent years EPA has pursued OBD cases against manufacturers including Honda, Jaguar and Toyota.

On-Board Diagnosis Settlements

Civil Enforcement | Cleanup Enforcement | Criminal Enforcement

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