P0622
PowertrainCharging Systemmoderate severityGenerator Field "F" Control Circuit
What P0622 Means
The PCM detected a fault in the generator field (F terminal) control circuit. This affects the alternator's ability to regulate output.
Symptoms
- Under- or over-charging
- Battery warning light
- Electrical system instability
Common Causes
- Faulty field control circuit
- Alternator internal fault
- Wiring open or short
- Faulty PCM driver
Diagnostic Steps
- Test field control circuit voltage
- Inspect wiring and connectors
- Check alternator output under load
- Replace alternator or repair wiring
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