Powertrain
generic / SAE
P0621
Generator Lamp L Control Circuit
The control circuit for the generator warning lamp output (L terminal) reports a fault.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number6 / 21
Possible causes
- Lamp circuit open or shorted high
- Alternator regulator fault medium
Symptoms
- Check engine light on
- Possible limp mode or no-start
- Multiple follow-up faults across modules
- Reset/relearn may be needed after repair
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 80–500 €
- Estimated time: 0.5–2 h
- Component: alternator
- Component: alternator wiring
- MIL / check engine light
Sources
References
sae:J2012