P0C55Drive Motor B Position Sensor Circuit A
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0C55 is the general circuit code for the first pickup winding (Circuit A) of the resolver on the second traction motor. It applies when the motor B controller recognises a fault on that winding but cannot assign it to a low or high level. No manufacturer documents this code publicly. GM, which runs two motors in the Volt, ELR and the two-mode trucks, files motor B winding faults under P0C57 and P0C58 instead. Compared with P0A45, which reports the motor B angle signal as a whole, P0C55 narrows the search to one winding and its two wires. CARB requires such circuit faults to be detected separately from out-of-range faults. The result is usually a warning lamp and the loss of motor B for drive or charging.
- What you may notice
- Check engine lamp with hybrid system warning
- Motor B unavailable, reduced propulsion
- Engine may run more often because the second motor is offline
- Likely causes
- LikelyOpen wire or loose terminal in the motor B Circuit A lines
- PossibleDamaged or corroded motor B resolver connector
- PossibleDefective first pickup winding in the motor B resolver
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.