P0EC4A/C Refrigerant Temperature Sensor B Range/Performance
- Generic OBD-II code · Powertrain
- Needs a drive cycle to confirm a fix
- How the car detects it
- P0EC4 is a plausibility fault: sensor B delivers a voltage inside its normal window, yet the temperature it reports does not agree with other information. No manufacturer documents P0EC4 publicly. A well-described pattern comes from GM's 2012 Volt (P153B, Type B): once the compressor has been off for over an hour, the low-side refrigerant temperature must lie within 10 degrees Celsius of the raw ambient temperature and of the value derived from high-side pressure; the check runs only when no circuit codes are active. A drifting sensor, poor thermal contact or a wrong charge can fail such a comparison. The A/C usually still works but may be controlled poorly. Electrical faults of sensor B: P0EC1 to P0EC3.
- What you may notice
- Uneven or weak cooling, compressor cycling oddly
- Fault often appears only after a long standstill
- Likely causes
- LikelySensor B drifting out of tolerance
- PossibleSensor not seated properly on the pipe, poor thermal contact
- RareIncorrect refrigerant charge shifting the comparison values
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.