P2E7FA/C Compressor Control Module Internal Temperature Sensor B Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2E7F is the low-signal counterpart: sensor B inside the compressor control module reports a value below its valid band, which for a sensor with falling output means an impossibly hot reading. GM's comparable code on the compressor IGBT sensor is P0D78: the 2011 Volt fails above 274 °C, the 2018 and 2019 tables above 150 °C, with the compressor detecting the condition itself and passing it on over GMLAN, Type B. No manufacturer documents P2E7F. A short on the sensor path is the usual explanation. Genuine overheating of the power stage, for instance from too little refrigerant flow, should still be ruled out, because controllers like the one in a Mitsubishi Heavy Industries patent slow or stop the compressor when it runs too hot. The cold side is P2E7E.
- What you may notice
- Compressor derates or shuts down for overheat protection
- Air conditioning blows warm, battery cooling may be limited
- MIL possible after two drive cycles depending on manufacturer
- Likely causes
- LikelyShort circuit in the sensor B path on the control board
- PossibleMeasuring circuit of the compressor controller defective
- RarePower stage genuinely overheating, e.g. low refrigerant charge
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.