Faulty Engine Control Module (ECM)
Engine Control Module (ECM) Harness power supply circuit is open or shorted
Engine Control Module (ECM) Programming
Engine Light ON (or Service Engine Soon Warning Light)
Engine may not start
The Engine Control Module (ECM) continuously monitors its internal memory status, internal circuits, and output signals to the throttle actuator. This self−check insures that the ECM is functioning properly. If any malfunction is detected, the ECM will set the code and illuminate the engine light.