New requirements for large trucks and buses help clean the air (12/8)
On-board diagnostic systems (OBD) have been required on passenger cars since the mid-1990s, and will now be required on heavy-duty vehicles. OBDs monitor emission control systems and detect malfunctions. The system alerts the driver of the problem, enabling a service technician to diagnose and properly repair the problem.
The final rule is part of EPA’s efforts to work with the California Air Resources Board to develop a consistent national heavy-duty OBD program. OBD systems are an important tool for potentially improving air quality by helping states to meet National Ambient Air Quality Standards.