Circuit/System Description

The ECM uses the 14V power module turn on control circuit to control the output of the 14V power module, often referred to as the accessory DC power control module. This 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 if the charging system malfunctions. ECM should detect high voltage when the duty cycle voltage is commanded high and a low voltage when the duty cycle voltage is commanded low on the 14V power module control circuit.