P0D65: Hybrid/EV Battery Pack Cooling Fan Enable Circuit Low
What to do
Listen for the battery cooling fan running when the car is parked and locked — if it is, expect a flat 12-volt battery within a few days. If instead the fan never runs, expect reduced power and slower charging in hot weather. Either way it should be fixed rather than lived with.
What this code means
The enable circuit for the traction battery cooling fan is faulty.
An enable line is a separate wire from the speed command, and the split exists for a reason. Speed is a modulated signal that says how hard to run. Enable is a plain permission that says whether the fan may run at all — and having it separate means a module can shut the fan down decisively without having to command zero and hope.
Which direction the fault takes decides how it presents. Enable stuck off means the fan never runs, the pack overheats and derates in hot weather, and every symptom points at the battery. Enable stuck on means the fan runs constantly, including with the car asleep — that is a 12-volt load that never switches off, which is the P0CC6 pattern again and ends as a flat battery in the morning.
Both are worth fixing quickly and for different reasons, and the audible one is the easier: a battery fan that can be heard running in a parked, locked car is telling you exactly what is wrong.
The circuit is at or below its lower limit, usually a short to earth. Depending on the design this can leave the fan permanently enabled.
Likely causes
Start here
- Faulty hybrid battery cooling fan · specialist
- Open circuit in control wiring · specialist
- Corroded or loose connector · specialist
Less common
- Control module driver failure · specialist
- Damaged wiring harness · specialist
Symptoms
Components involved
Information, not instruction
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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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