P0620
PowertrainCharging Systemmoderate severityGenerator Control Circuit
What P0620 Means
The PCM detected a fault in the generator (alternator) control circuit. This can affect charging system regulation.
Symptoms
- Battery warning light
- Under- or over-charging
- Dim or flickering lights
Common Causes
- Faulty alternator/generator
- Control circuit wiring fault
- Corroded connectors
- Faulty PCM
Diagnostic Steps
- Test charging system output
- Check generator control circuit wiring
- Inspect connectors and grounds
- Replace alternator if faulty
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