Circuit/System Description

The engine control module (ECM)/powertrain control module (PCM) uses the generator turn ON signal circuit to control the load of the generator on the engine. A high side driver in the ECM/PCM applies a voltage to the voltage regulator. This signals the voltage regulator to turn the field circuit ON and OFF. The ECM/PCM monitors the state of the circuit. The ECM/PCM should detect low voltage on circuit when the ignition is ON and the engine is OFF, or when the charging system malfunctions. With the engine running, the ECM/PCM should detect high voltage on the circuit. The ECM/PCM performs key a ON and RUN test to determine the status of the circuit.