L Terminal Circuit

Circuit Description
When the ignition switch is in the Run position, the PCM supplies voltage to the L terminal of the generator, turning on the digital voltage regulator. When the engine is started, the regulator senses the AC output of the stator via an internal circuit. The regulator will then control the output of the generator by pulse width modulating the field current. This PWM signal is fed back to the PCM on the F terminal circuit. The PCM monitors generator output using this signal. The PCM controls the charge warning indicator in the I/P via Class 2 serial data.

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 Charging System Check in Starting and Charging for further information and generator diagnosis.
Use a scan tool in order to diagnosis the generator circuits. A scan tool displays Commanded GEN Off when there is a problem with the L-terminal circuit.
L Terminal Circuit and F Terminal Circuit shorted together causes GEN PWM to remain fixed at approximately 25%.

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.