P0538: Air Conditioning Evaporator Temperature Sensor Circuit High
What to do
Driveable, with air conditioning that may not work.
What this code means
The evaporator temperature signal is above its plausible range — usually an open circuit or a disconnected sensor. The mirror of the circuit-low fault, and diagnosed the same way.
Likely causes
Start here
- Open circuit in sensor wiring · moderate
- Faulty air conditioning evaporator temperature sensor · specialist
- Corroded or loose connector · moderate
Less common
- Signal wire 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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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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