P0A03: Motor Electronics Coolant Temperature Sensor A Circuit High
What to do
Expect reduced performance. Ask for the wiring and connector to be inspected as well as the sensor — on this part of the car a damaged harness is at least as likely as a failed sensor.
What this code means
The power electronics coolant temperature circuit reads above its valid range — an open circuit or a short to supply, which the module cannot distinguish between. Read as impossibly cold coolant, which is implausible enough that the module distrusts the sensor rather than acting on the value, and falls back to conservative power limits.
A connector that has corroded reads identically to a broken wire. On a low-temperature circuit routed at the front of the vehicle where stone damage and road salt reach it, both are plausible and the harness deserves inspecting before the sensor is replaced.
Likely causes
Start here
- Open circuit in sensor wiring · moderate
- Corroded or loose connector · easy
- Faulty inverter coolant temperature sensor · moderate
Less common
- Wiring shorted to voltage · moderate
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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