P2CB2Charge Air Cooler Coolant Pump B Underspeed
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- With P2CB2 the speed reported by charge air cooler pump B stays below what it should reach. The motor is braked mechanically or gets too little power: a dragging bearing, debris or sludge at the impeller, a weak supply or a high-resistance connector. No manufacturer documents P2CB2 publicly. GM's pump A version, P2B84 in table 25OBDG04B, trips on a reported speed below −115 rpm, effectively a stopped or backward-turning rotor, in 8 of 10 samples with at least 11 V, Type B. GM bulletin 23-NA-102 traced such pump faults on the 3.0-litre Duramax to water getting into the plug of pump M10, a reminder to inspect the connector first. Less flow means warmer charge air and possible power loss. A rotor that cannot move at all is P2CB3.
- What you may notice
- MIL on after two trips
- Charge air runs hot, engine power reduced under load
- Likely causes
- LikelyDragging bearing or sludge slowing the rotor of pump B
- PossibleWater or corrosion in the pump connector raising resistance
- PossibleLow supply voltage from a poor ground or weak battery
- 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 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.