Powertrain, generic

P0EC0 A/C Compressor Motor Phase W Current Sensor Circuit

Check engine lightUsually off

EmissionsNot relevant

Drive cycleNot required

Limp modeNo

P0EC0 is the umbrella circuit code for the phase W current sensor in the inverter of an electric A/C compressor. It applies when no valid W-phase value arrives at all, without a split into high, low or implausible; those cases have their own codes P0EB8 to P0EBA. Like the phase V circuit code P0EBB it is numbered out of sequence. No manufacturer documents P0EC0 publicly. For orientation, GM's 2011 Volt checked each compressor phase with the motor stopped and set a fault when the W reading stayed beyond plus or minus 68 A in 30 of 60 samples (older codes P0D7E and P0D7F, Type B, 12 V reset needed). Without the W value the motor control cannot run the compressor. U-phase circuit code: P0EB1.

Likely causes

Failed W-phase current sensor or inverter board

Interrupted W-phase sensing path inside the inverter

Missing supply voltage for the current sensors

Symptoms

Electric A/C compressor does not start
No cabin cooling, battery cooling via refrigerant may be limited

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€150–2,500

Time1–5 h

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

Parts involved

ac compressor motor phase w current sensorac compressor module

References: gsi.ext.gm.com, law.cornell.edu.