Circuit Description

Engine controls diagnostic system check must be starting point for any driveability complaint diagnosis. Perform a careful visual and physical inspection of Powertrain Control Module (PCM) and engine grounds for cleanliness and tightness. Engine controls diagnostic system check is an organized approach to identifying a problem created by an electronic engine control system malfunction.

PCM controls the Malfunction Indicator Lamp (MIL) by providing a ground path through MIL control circuit to turn On the MIL. When ignition switch is turned to RUN position, MIL will remain On until engine is running, if no DTC are stored. If MIL is illuminated, then engine stalls, MIL will remain illuminated so long as ignition is in RUN position.