P2B22Hybrid/EV Electronics Coolant Temperature Sensor B 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
- P2B22 says the signal voltage of electronics coolant sensor B has fallen below its valid band. Since these sensors are NTC thermistors, a low voltage would mean an absurdly hot coolant, so the usual explanation is a signal wire touching ground, moisture bridging the connector or an internally shorted element. No manufacturer documents P2B22 publicly; NTN-SNR's catalogue calls it a too-small signal of sensor B. GM's 2019 HPC2 table shows typical numbers for the matching sensor A code P0CF0: below 4 % of the 5 V reference (0.2 V) for 4 s within 5 s, with more than 10.2 V supply, Type B. CARB requires such out-of-range checks on inverter cooling inputs. Because a hot value is taken seriously at first, the pump runs harder and power can be limited. P2B23 is the opposite case.
- What you may notice
- Warning lamp or hybrid system message
- Electronics coolant pump and fans running at high output
- Reduced electric drive or charging power
- Likely causes
- LikelySensor B signal wire chafed through and shorted to ground
- PossibleWater or coolant in the sensor connector
- PossibleInternally shorted sensor 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.