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.
Low severity. Can I keep driving?Yes, you can keep driving. The air conditioning may not work.
Symptoms
- Electric A/C compressor does not start
- No cabin cooling, battery cooling via refrigerant may be limited
Most 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
What to check, in order
Start with the simplest. You can tick off each step.
What each character of P0EC0 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- E: Subsystem depends on the code range
- C0: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0EC0?
Yes, you can keep driving. The air conditioning may not work.
What causes code P0EC0?
The most common causes are: failed W-phase current sensor or inverter board; interrupted W-phase sensing path inside the inverter; missing supply voltage for the current sensors.
Related codes
- P0EB8A/C Compressor Motor Phase W Current Sensor Circuit High
- P0EB9A/C Compressor Motor Phase W Current Sensor Circuit Low
- P0EBAA/C Compressor Motor Phase W Current Sensor Range/Performance
- P0EBBA/C Compressor Motor Phase V Current Sensor Circuit
- P0EB1A/C Compressor Motor Phase U Current Sensor Circuit
- P0D7EA/C Compressor Motor Phase W Current Low
- P0D7FA/C Compressor Motor Phase W Current High
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.