P0621
PowertrainCharging Systemlow severityGenerator Lamp "L" Control Circuit
What P0621 Means
The PCM detected a fault in the generator lamp (L terminal) control circuit. The charge warning indicator may not operate correctly.
Symptoms
- Charge light stays on or off
- Charging issues
- Warning lamp malfunction
Common Causes
- Faulty generator L terminal circuit
- Wiring open or short
- Corroded connector
- Faulty alternator
Diagnostic Steps
- Check L terminal circuit continuity
- Inspect connectors for corrosion
- Test alternator output
- Repair circuit or replace alternator
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