P0538A/C Evaporator Temperature Sensor Circuit High
- Generic OBD-II code · Powertrain
- How the car detects it
- The evaporator temperature sensor, an NTC thermistor behind the evaporator, prevents icing: near 0–3 °C the compressor is switched off or reduced. Usually the climate module reads it and reports body codes; P0535–P0539 only arise where the engine module controls the compressor and reads the sensor. P0538 means the signal voltage is above its limit – an open sensor, signal or ground line, or a short to positive; with an NTC that reads as implausibly cold, so the system assumes icing and usually locks out the compressor. No manufacturer document available to us uses this code; the description follows CARB's input component rules.
- What you may notice
- Air conditioning not cooling (compressor locked out)
- Vents blowing warm
- Usually no check engine light
- Likely causes
- LikelyConnector off or corroded, wire open
- LikelySensor open internally
- PossibleGround line open
- RareShort to positive
- Repair
- Medium · Often possible to do yourself.Typical cost: €30 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.