P0CF0Hybrid/EV Electronics Coolant Temperature Sensor A Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- The signal voltage of the electronics coolant temperature sensor drops close to zero, which almost always means the signal wire touches ground or the sensor is shorted internally. Low refers to the voltage, not to the temperature. GM sets the code below 2 % of the 5 V reference (0.1 V) in the 2011 Volt, the ELR and the 2016 HPC2 table, and below 4 % (0.2 V) in the 2016 Volt and the 2019 HPC2 table. Counting is 16 of 20 samples at 250 ms or 4 s in a 5 s window, with more than 9 or 10.2 V supply, Type B, two trips. The open or high case is P0CF1, a plausible but wrong value is P0CEF. With no usable reading, the controller assumes the worst, runs the pump and can limit inverter and charging power.
- What you may notice
- Malfunction indicator lamp or hybrid warning
- Scan tool shows an implausibly high coolant temperature
- Pump running constantly, power or charging reduced
- Likely causes
- LikelySensor signal wire shorted to ground
- PossibleInternally shorted temperature sensor
- PossibleWater in the connector bridging signal and ground
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €40 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.