Pinpoint Test F: DTC P0620, P065B: Notes
DTC P0620, P065B
Refer to Wiring Diagrams Cell 12 for schematic and connector information.
Normal Operation and Fault Conditions
The PCM monitors the generator output via the generator monitor (GENMON) circuit. The PCM uses the generator command (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 not be able to control the generator output. When the engine speed is greater than 2, 000 rpm, the generator defaults to a steady voltage output of 13.5 volts and the PCM sends a request to the IPC to illuminate the charging system warning indicator. A GENCOM circuit fault can be confirmed by viewing the PCMPID generator command line fault (GENCMD_LF) (YES status indicator fault).
Diagnostic Trouble Code (DTC) Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| P0620 | Generator Control Circuit | The PCM sets this DTC if the GENCOM circuit, "A" sense circuit, or B+ circuit is open or shorted to ground. |
| P065B | Generator Control Circuit Range/performance | The PCM sets this DTC when the generator reports an internal regulator failure. |
Possible Sources
- Fuses
- Generator
- PCM
- Wiring, terminals or connectors
Visual Inspection and Diagnostic Pre-checks
- Verify BJB fuse 55 (10A).
- Verify high current BJB fuse 7 (275A).
- Inspect the high current BJB for loose or corroded connections.