Powertrain, generic (extended)

P2E80 A/C Compressor Control Module Internal Temperature Sensor B Circuit Intermittent/Erratic

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

With P2E80 the controller sees the reading of sensor B, a second internal thermometer in the compressor electronics, flicker: values leap or vanish for an instant and then look normal again. Set criteria for P2E80 are not published by any manufacturer. For the 2019 Volt, GM lists the IGBT counterpart P0D79 merely as a code that must be inactive before its rationality check P0D76 starts. A Hyundai patent dealing with sensors on inverter power switches separates the patterns: dropouts spread irregularly over time point to bad contact, whereas a value stuck at one number suggests a short. Loosened board connectors, cold solder joints and interference are prime suspects. Rule out the low-voltage feed, ground and network line first; when the fault stays, the compressor assembly is normally replaced as one unit.

Likely causes

Loose contact or cold solder joint in the sensor B circuit
Electrical interference from the inverter switching on the measuring line
Fluctuating 12 V supply or ground of the compressor controller

Symptoms

  • A/C cuts out and recovers sporadically
  • Fault may be stored without any noticeable effect

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€50–2,500
Time0.5–5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

ac compressor cm internal temp sensor bac compressor module

Related codes

P2E7CP2E7DP0D74P0D79

References: image-ppubs.uspto.gov, gsi.ext.gm.com, law.cornell.edu.