System Description

PURPOSE
The operation of the charging system is monitored by the Powertrain Control Module (PCM). The PCM monitors charging system loads and adjusts idle speed accordingly. The PCM also reports to the Instrument Panel Cluster (IPC) when the charging system is not working and tells it to turn on the volts telltale.

OPERATION
The generator provides voltage to operate the cars electrical system and to charge its 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 by the rectifier bridge and is supplied to the electrical system at the battery terminal.

The main parts of the charging system are the generator and the Powertrain Control Module (PCM).

The PCM supplies about 5 volts through the "L" circuit of the generator. If the generator becomes inoperative, the PCM sees the fault through the "L" circuit and tells the Instrument Panel Cluster (IPC) to turn on the volts telltale.

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

GENERATOR ASSEMBLY
The generator assembly is mounted to the front of the engine on the passenger side of the vehicle. This generator uses an internal regulator which features built-in fault detection. This generator is not to be disassembled for service.

DIAGNOSIS
The Chart C-19 PCM Controlled Generator (Functional Check) will diagnose the generator "F" and "L" circuits. Diagnosis of the remaining circuit(s) are covered in Charging System.