PCM Controlled Generator

Generator Usage:

The generator assembly is mounted to the front of the engine on the passenger side of the vehicle. The CS-type generator uses an internal regulator which features built-in fault detection. The generator used on this vehicle, is not to be disassembled for service.

The generator provides voltage to operate the vehicles electrical system and to charge the vehicles battery. A magnetic field is created when current flows through the rotor.

This field rotates as the rotor is driven by the engine, creating an AC voltage in the stator windings. The AC voltage is converted to DC voltage by the rectifier bridge and is supplied to the electrical system at the battery terminal.

The operation of the charging system is monitored by the PCM. The PCM monitors the charging system loads and adjusts the idle speed accordingly. The PCM also sends information to the Instrument Panel Cluster (IPC) when the charging system is inoperative and tells the IPC to illuminate the volts telltale lamp.

The PCM supplies 5 volts through the L circuit to the generator. If the generator becomes inoperative, the PCM can detect the fault through the L circuit and tell the IPC to illuminate the volts telltale lamp.

The PCM monitors the duty cycle of the generator through the F circuit. As the generator load increases, the PCM will adjust the idle speed accordingly. If the IPC does not see any activity from the PCM on the F circuit, the IPC will illuminate the volts telltale lamp.

If the Voltage telltale is ON and the (L) terminal voltage is low while the PCM is commanding the generator ON for more than 30 seconds OR

If the voltage telltale is ON and the (F) terminal PWM is less than 5 percent while engine RPM is less than 2500 for more than 30 seconds DTC P0620 will set.

Use the DTC P0560 System Voltage, and DTC P0620 Generator Performance to diagnose the charging system.