P0C0ADrive Motor B Phase U-V-W Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0C0A reports that a phase line of drive motor B reads too high, typically a short to the positive high-voltage rail or a high-side power switch that stays on. It mirrors P0C07 for motor A and completes the motor B trio with P0C08 (open) and P0C09 (low). No manufacturer documents P0C0A publicly; GM only uses P0C08 for motor B phase circuits, based on missing phase current. CARB requires hybrid components to be monitored for circuit faults. A phase stuck high leads to uncontrolled current, so the inverter switches motor B off immediately and P0C04 may be stored as well. For the driver this means a warning lamp, reduced propulsion and, on electric all-wheel drive, loss of the driven axle.
- What you may notice
- Immediate shutdown of motor B with warning lamp
- Reduced performance or loss of electric all-wheel drive
- Likely causes
- PossibleShorted high-side power switch in the motor B inverter
- PossiblePhase cable of motor B shorted to the positive high-voltage path
- RareFaulty gate driver holding a switch on
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €200 – €6,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.