P0C45: Hybrid/EV Battery Pack Coolant Temperature Sensor A Circuit High
What to do
As P0C42.
What this code means
The battery pack's coolant temperature sensor is reading above its valid range, an instrument fault rather than genuinely hot coolant. Why coolant temperature is a different question from cell temperature, and what the gap between them tells you, are at P0C42.
Likely causes
Start here
- Faulty engine coolant temperature sensor · moderate
- Corroded or loose connector · easy
Less common
- Low coolant level · easy
- Coolant leak into the sensor connector · 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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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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