P0CFF: Hybrid/EV Battery Pack Coolant Pump A Stuck/Stalled
What to do
If it appeared on a very cold morning and has not returned, thick coolant may have stalled a healthy pump — worth mentioning, because it is a much better outcome than the alternative. Otherwise expect a physical cause: debris or a seizing pump. Have the coolant condition checked at the same time, because a pump fitted into a dirty circuit tends to stall again. Expect reduced power and slower charging until it is done, and treat that as the car protecting the battery rather than a second fault.
What this code means
The battery pack's coolant pump has been commanded to turn and has not turned.
The last code in P0Cxx, which closes the block at 256 of 256 — which is fitting, because it is one of the plainest. The module knows the pump is stalled rather than merely underperforming: current is flowing and rotation is not happening. That single fact rules out the entire electrical half of the usual list before anything is measured.
So the causes are physical, and the reasoning is the same as at P0C2A. Debris is first — coolant circuits accumulate casting sand, sealant, corrosion products and the remains of any stop-leak that has ever been added, and an electric pump's clearances are small. A seized bearing is second. And the case that is not a fault at all is third: a pump can stall on a hard frost against thick coolant and run perfectly once warm, which is worth eliminating before anything is bought.
What it costs is not subtle. Without pack cooling the car protects the battery the only way it can — limiting power, refusing rapid charging, and in warm weather limiting how far it will go. Heat is what ages a traction battery fastest after time itself, so this is worth fixing promptly even though the car still drives.
Likely causes
Start here
- Seized pump motor · specialist
- Faulty electric coolant pump · moderate
Less common
- Restricted coolant flow or blocked passage · moderate
- Low coolant level · easy
- Battery pack cold-soaked in freezing weather · easy
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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