Loose or poor battery terminal connection
Low battery charge
ECM power supply circuit is open or shorted
Engine Light ON (or Service Engine Soon Warning Light)
Engine may not start
The ECM continuously monitors its own internal memory status, internal circuits, and output signals transmitted 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.