December 14, 2006

EPA proposes onboard diagnostic system for new large trucks and buses

Washington, D.C. – For the first time, the U.S. Environmental Protection Agency (EPA) is proposing to require the emissions control systems of large diesel and gasoline highway trucks and buses to be monitored similarly to passenger cars. The EPA’s proposed regulation for onboard diagnostic (OBD) systems for these vehicles would help ensure that emissions control systems work properly for the useful life of heavy-duty on-road vehicles.

OBD systems, used in passenger vehicles since the mid-1990s, monitor emissions control components, detect the need for emission-related repairs, alert the vehicle’s operator of the problems, and help inform service technicians of existing problems for proper repair. The OBD systems for highway trucks will work the same way. The proposal also makes changes to certain existing OBD requirements for smaller highway diesel trucks. For more information, visit

Connect with