P2B26Hybrid/EV Electronics Coolant Temperature Sensor C 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 voltage on the signal line of sensor C, the third coolant sensor in the power electronics loop, is lower than the controller accepts. Low means voltage here, not temperature: on an NTC sensor it corresponds to an implausibly hot value. A pinched or chafed lead touching the body, a short inside the sensor or coolant that has crept into the plug are the usual findings. No manufacturer documents P2B26 publicly; the NTN-SNR catalogue describes a signal of sensor C that is too small. CARB requires inverter cooling inputs to be checked for values outside their range; for sensor A, GM uses 4 % of the reference (0.2 V) as the lower limit. Since the reading suggests overheating, controllers tend to run pump and fans hard and may reduce power. The open or high case is P2B27, a plausible but wrong value P2B25.
- What you may notice
- Warning lamp or system message
- Pump and radiator fan running hard even when cool
- Reduced power in some situations
- Likely causes
- LikelySensor C signal lead pinched or chafed against ground
- PossibleCoolant wicking into the sensor plug
- PossibleShorted sensor C element
- 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.