P2B83Charge Air Cooler Coolant Pump A Overspeed/Air In System
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2B83 concerns the electric pump that keeps coolant moving through a water-cooled charge air cooler. When the impeller runs in air instead of liquid, load vanishes and the motor spins up. GM documents this in its 2025 diesel table 25OBDG04B: a reported pump speed of 8,500 rpm or more in 8 of 10 one-second samples sets the code, provided the pump is fitted and enabled, the engine is not cranking and relay voltage is at least 11 V; Type B, MIL after two trips. GM's 3.0-litre Duramax uses such a pump (M10, bulletin 23-NA-102). GM's bulletin 18-NA-291 for the supercharged LT4 notes that this pump switches off once it draws air, so the loop must be vacuum filled. Too little speed is P2B84, the B pump has P2CB1. Hot charge air can cut power.
- What you may notice
- Check engine light after two drives with the fault
- Reduced power under load because the intake air gets hot
- Falling level in the charge air cooler coolant reservoir
- Likely causes
- LikelyAir pocket in the charge air cooler loop after service or a leak
- PossibleLow coolant level in the separate low-temperature loop
- RareImpeller loose or broken on the pump shaft
- RarePump electronics reporting an implausible speed
- 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: €80 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.