P0A01: Motor Electronics Coolant Temperature Sensor A Circuit Range/Performance
What to do
Ask for this sensor to be compared against the other temperature readings on a fully cold car — that comparison usually settles it in one measurement. If the reading turns out to be accurate, the cooling system itself needs attention rather than the sensor.
What this code means
The power electronics coolant temperature reading is electrically valid but implausible — commonly a value that never changes, or one that does not rise as the inverter works.
The cold-soak comparison used throughout this corpus settles it in a single reading. After the vehicle has stood overnight every temperature sensor on it is measuring the same air, so engine coolant, intake air, ambient and this one should agree within a few degrees. Whichever disagrees at that moment is the faulty one, and no further reasoning is needed.
A reading that is genuinely correct but higher than expected points somewhere else entirely: a low-temperature radiator blocked with debris, an electric pump not running, or coolant that has been lost. Those are worth eliminating before the sensor is condemned, because the consequence of a real cooling problem here is considerably worse than a sensor.
Likely causes
Start here
- Faulty inverter coolant temperature sensor · moderate
- Low inverter coolant level · moderate
Less common
- Restricted low-temperature radiator · moderate
- Faulty inverter coolant pump · moderate
- Air trapped in the inverter cooling circuit · specialist
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
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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