OBD I Systems

OBD I vehicles use the same PCM, controller area network (CAN) serial data communication link, J1962 Data Link Connector, and PCM software as the corresponding OBD II vehicle. The only difference is the possible removal of the rear oxygen sensors, fuel tank pressure (FTP) sensor, EVAP canister vent valve, and a different PCM calibration. Starting in the 2006 model year, all Federal vehicles from 8, 500 to 14, 000 lbs. Gross Vehicle Weight Rating (GVWR) will have been phased into OBD II and OBD I systems will no longer be utilized in vehicles up to 14, 000 lbs. GVWR.