P0C0A code meaning
Drive Motor B Phase U-V-W Circuit High
Powertrain system Generic code P0Cxx codes Check engine light
What P0C0A means
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.
P0C0A at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 10 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0C0A
- Immediate shutdown of motor B with warning lamp
- Reduced performance or loss of electric all-wheel drive
Common causes of P0C0A
- PossibleShorted high-side power switch in the motor B inverter
- PossiblePhase cable of motor B shorted to the positive high-voltage path
- Less likelyFaulty gate driver holding a switch on
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Drive motor b phase uvwDrive motor b inverter
What each part of P0C0A means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| C | Area: hybrid propulsion. |
| 0A | The exact fault in that area. |
What to do next
- Note P0C0A and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0C0A
What does P0C0A mean?
P0C0A means "Drive Motor B Phase U-V-W Circuit High". 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 is a generic code, so it means the same on every make.
Is it safe to drive with P0C0A?
Drive gently and only to a workshop. With P0C0A the car can go into limp mode (reduced power) to protect itself.
Will P0C0A fail an emissions test?
Yes, it can. P0C0A is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0C0A to fix?
Difficulty: workshop only. A typical repair takes 1 to 10 hours of work. This is a job for a workshop.
Will P0C0A clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.