On-board diagnostics for heavy-duty vehicles: Considerations for Mexico

On-board diagnostic (OBD) systems monitor the performance of engine and aftertreatment components including those responsible for controlling emissions.1 Historically, OBD systems were first deployed in light duty vehicles (LDVs), in 1991 the United States and 10 years later in Europe. Those first OBD systems were very basic and had very little standardization, meaning that each manufacturer adopted a different system to derive and provide data to drivers and mechanics. By 1996 the OBD system was standardized and the monitoring and emission limits for malfunction were unified across US manufacturers. OBD was introduced to heavy-duty vehicles (HDV) in 2005 in Europe. The phase-in schedule of U.S. Environmental Protection Agency (EPA) OBD requirements started with medium-duty vehicles, as an extension of technologies adopted for LDVs, and now covers the heavier categories. Intended to support the regulatory process around revision of heavy-duty emissions standards in Mexico (NOM 044), this memo focuses on the deployment schedule for OBD on HDVs for Europe and the U.S. and presents the main technical features of these two advanced OBD programs.