Circuit Description

PCM uses the "L" terminal circuit to control the generator. A driver within the PCM allows PCM to turn generator on and off. When generator operation is desired, PCM sends a 5-volt signal to voltage regulator via the "L" terminal circuit, causing voltage regulator to begin controlling generator field circuit. Once generator is enabled by PCM, voltage regulator controls generator output independently of PCM. Under certain conditions, PCM can turn off generator by turning off the 5-volt signal on the "L" terminal circuit. A fault detection circuit in PCM monitors the state of the "L" terminal circuit and if it senses a voltage other than what is expected, DTC will set. Voltage regulator also contains a fault detection circuitry and will ground the "L" terminal circuit if it detects a problem, setting DTC. If DTC is set, PCM will illuminate the CHARGE indicator light.