Faulty Engine Control Module (ECM)
Engine Control Module (ECM) harness is open or shorted
Engine Control Module (ECM) circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
The Engine Control Module (ECM) uses two circuits to control and monitor the state of the 14V power module, often referred to as the accessory DC power control module. The control circuit functions much like the L Terminal circuit on a generator equipped vehicle. A high side driver in the ECM applies a duty cycled voltage to the 14V power module. The duty cycle controls the 14V power module output. The ECM monitors the state of the 14V power module control circuit. The ECM will detect faults on the 14V power module control circuit when the vehicle is ON.