The computer sees battery voltage above its normal range. The driver may notice very bright lights, blown bulbs or a battery warning.
Likely causes, most common first
- Faulty alternator regulator
- Poor regulator sense connection
- Wrong jump start or external charger
- Poor ground
Parts usually involved
- Alternator
- Battery terminals
- Ground cables
Test before you replace
Measure charging voltage at the battery with the engine running and check the regulator wiring and grounds.
General guidance for generic OBD2 codes. Always follow the maker's procedure for the car in front of you.