P0A77
Generator Phase W Current High
Phase W current of the generator exceeds the expected window. Indicates phase short or stalled rotor.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
Common causes
Ordered by how often each turns out to be the cause.
- Short between motor phasesCommon
- Rotor stalled - high stall currentPossible
Parts involved
- Generator Phase W
- Inverter
P0A77 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.