P0E1F: Hybrid/EV Battery Pack Coolant Pump A Control Circuit Driver Current/Temperature Too High
What to do
The car will drive. Expect slower charging and reduced power in hot weather. Ask for what the circuit drives to be tested before the control module is replaced — the module is usually protecting itself from a failing pump or a seized valve, and a new module will report the same fault.
What this code means
The module's output driver for the first battery coolant pump has exceeded its current or temperature limit.
This code is about the module's output stage rather than about the thing it drives, and that distinction is the whole of its diagnostic value.
A control module does not switch a pump or a valve with a mechanical relay; it does it with a semiconductor driver built into the module. That driver has its own current and thermal limits, and this family of codes is the driver reporting that it reached them.
Which means the module is protecting itself from the load, and the load is usually the fault. A motor with worn bearings, a valve seizing, a partially shorted winding, or a chafed wire touching earth all draw more current than the driver will pass — so the module shuts the output down and stores this rather than a fault against the component.
The trap is reading it as a module failure. A car that stores a driver current code and gets a new control module will usually store it again within days, because the excessive load is still connected. Measure what the output is driving before condemning what is driving it — and note that the reverse also happens, since a genuinely failed driver stores the same code with a healthy load on the end of it.
On a pump the commonest excessive load is worn bearings or a blockage. A pump forcing coolant through a restriction, or one whose bearings are dragging, draws steadily more current as it deteriorates — which is why this can be an early warning rather than a failure, if it is read as one.
Likely causes
Start here
- Faulty inverter coolant pump · specialist
- Damaged wiring harness · specialist
- Corroded or loose connector · specialist
Less common
- Control module driver failure · specialist
- Restricted coolant flow or blocked passage · 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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