Normal Operation: Notes

The PCM monitors the generator output via the GENMON circuit. The signal that is monitored by the PCM on the GENMON circuit is a controlled frequency range. If the signal is outside of this prescribed range, the PCM is be unable to read the signal. When the engine rises above approximately 2, 000 rpm, the generator defaults to a steady voltage of approximately 13.5 volts and the PCM sends a request to the Instrument Cluster (IC) to illuminate the charging system warning indicator lamp.

• DTC P065B (Generator Control Circuit Range/Performance) - The PCM sets this DTC if the input frequency is continuously less than 80 Hz or more than 200 Hz. Additionally, if the signal shows a faulted condition that is happening in a fluctuating manner, the PCM tracks the fluctuations between faulted and normal conditions. This DTC can also set if the fluctuations occur frequently within a short amount of time.

This pinpoint test is intended to diagnose the following: 

• Wiring, terminals or connectors
• Generator
• PCM