P2B2CEngine Coolant Temperature Sensor 5 Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2B2C concerns a fifth coolant sensor whose signal is electrically valid but does not behave like coolant temperature: after a long cold soak it differs clearly from the other engine temperatures, it barely rises during warm-up although the engine heats normally, or it sits stuck at one value. CARB requires such rationality checks for coolant inputs that emission controls rely on. No manufacturer documents the set condition of P2B2C publicly; GM, which uses a sensor 5 input on the L3B and other engines, publishes only the electrical codes P2B2D and P2B2E for it. NTN-SNR names P2B2C a deviation or malfunction of the sensor 5 signal. Causes include a drifting element, a sensor in a branch with no flow because a valve or pump has failed, or poor contacts. Pure circuit faults are P2B2B, P2B2D and P2B2E.
- What you may notice
- MIL, often after a cold start
- Heater or fan behaviour that does not match engine temperature
- Likely causes
- LikelySensor 5 element drifting or sluggish
- PossibleNo coolant flow in the sensor's branch (stuck valve, failed pump, air)
- PossibleCorroded sensor connector
- RareEngine software needing an update
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €30 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.