P0620

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PINPOINT TEST 3: DTC P0620 - GENERATOR CONTROL CIRCUIT

Normal Operation

The PCM monitors the generator output via the generator monitor (GENMON) circuit. The PCM uses the generator communication (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.

- DTC P0620 Generator Control Circuit - If the GENCOM circuit or A sense circuit are open or shorted to ground, the PCM will set this DTC.

Possible Causes
- Fuse
- Wiring, terminals or connectors
- Generator
- PCM

Diagnostic Procedure

NOTE:Make sure battery voltage is greater than 12.2 volts prior to carrying out this pinpoint test.
NOTE:Do not have a battery charger attached during vehicle testing.

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