Normal Operation: Notes

The charging system supplies voltage to the battery and the vehicle electrical system through the battery B+ cable. The PCM monitors the generator output through a dedicated Local Interconnect Network (LIN) communication circuit. The generator uses this LIN circuit to communicate the desired voltage setpoint from the PCM to the voltage regulator. The generator also uses this LIN circuit to communicate the generator load and error conditions to the PCM.

• DTC U0120:13 (Lost Communication with Starter/Generator Control Module: Circuit Open) - Sets when the PCM does not detect communication through the LIN circuit. This can be a result of an open or short in the LIN circuit. This DTC also sets if the B+ circuit is open.

This pinpoint test is intended to diagnose the following: 

• Wiring, terminals or connectors
• Generator
• PCM