Normal Operation

The PCM monitors the generator output via the GENMON circuit. The PCM uses the GENCOM circuit to command the generator to either increase or decrease output. If the GENCOM circuit (generator control circuit) or the A sense circuit are open or shorted to ground, the PCM will be unable to control the generators output. When the engine rises above approximately 2, 000 RPM, the generator will default to a steady voltage of approximately 13.5 volts and the PCM will send a request to the Instrument Cluster (IC) to illuminate the charging system warning indicator lamp.

The generator (connector C102A) is connected to the PCM and the Battery Junction Box (BJB) along 3 circuits that are part of 2 wire harnesses (14290 - PCM/BJB and 12C580 - generator). The 2 wire harnesses are connected at C1045. The wire colors and circuit numbers for these circuits will change when passing through C1045. The following chart indicates the circuit number and wire color changes with respect to the harness in which they are located.

• DTC P0620:00 (Generator Control Circuit: No Sub Type Information) - If the GENCOM circuit or A sense circuit are open or shorted to ground the PCM will set this DTC.

This pinpoint test is intended to diagnose the following: 

• Fuse
• Wiring, terminals or connectors
• Generator
• PCM