P2B5EEngine Coolant Flow Control Valve Position Sensor Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2B5E reports a position sensor reading below its valid window. On GM's 3.0-litre Duramax the valve sends its angle as a raw SENT value in percent of 5 V; anything under 2 % counts as too low, and 80 failures in 100 samples at 6.25 ms set a Type B fault, provided there is no SENT communication fault and the relay supplies more than 11 V. A broken 5 V reference, a sensor ground issue inside the valve or a damaged signal wire can produce such a value. GM includes P2B5E in the LM2 chafed-harness condition of bulletin 21-NA-149. The engine computer loses the actual position and stops closed-loop control of coolant flow. High reading: P2B5F; plausibility: P2B60.
- What you may notice
- MIL on after two drives
- Coolant flow no longer regulated, warm-up slower
- Likely causes
- Likely5 V reference or signal wire interrupted or shorted to ground
- PossibleChafed engine harness on GM LM2 (21-NA-149)
- RarePosition sensor in the valve faulty
- 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: €50 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.