Generator Circuit Diagnosis (L Terminal)

Electrical Diagram:

CIRCUIT DESCRIPTION

The L terminal circuit from the generator is a discrete into the PCM. The PCM supplies the ignition voltage to the generator lamp feed. This ignition voltage is pulled low by the generator once the ignition switch supplies ignition 1 voltage. The voltage stays low until the generator turns. When the generator is up and running, the PCM detects ignition voltage. Therefore, with no failures with the vehicle's charging system, the lamp terminal circuit will go low (0.0 volts) when the ignition switch is powered up and then goes to the ignition voltage after the engine is started.

When the charging system detects a fault (circuit shorted to ground), the Driver Information Center will display Charging System Fault.

DIAGNOSTIC AIDS

A generator fault, such as a shorted output diode, malfunctioning regulator, open or shorted rotor, or open sense lead may cause a low battery charge. Refer to Engine/Engine Electrical for further information and generator diagnosis.

Use a scan tool in order to diagnosis the generator circuits. A scan tool displays Generator L Terminal Inactive when there is a problem with the L-terminal circuit.


TEST DESCRIPTION

The numbers below refer to the step numbers on the Diagnostic Table.

2. This isolates if the generator is at fault or if the PCM and wiring are at fault.

9. A poor connection at the generator will cause a no output condition.