P2E82Cold Start Engine Coolant Pump Overspeed
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2E82 flags an electric main coolant pump that spins faster than requested while the cold-start warm-up strategy runs. GM's 2025 ECM tables (25OBDG03B) subtract reported from requested speed, filter the result and fail the test when it falls below −200 rpm in 8 of 10 seconds; Type B, MIL after two trips. Required: low-flow coolant mode, catalyst warm-up active, a request that changes by less than 50 rpm per sample for 3 s, and inlet coolant at −40 °C or warmer. Outside cold start GM uses P26CE with a speed-dependent limit of −200 to −800 rpm. A pump that turns too freely often moves air instead of coolant, so low coolant or trapped air are the first suspects. A GM patent compares pump speed and current with targets to find such faults.
- What you may notice
- Check engine light after two trips
- Gurgling noises or weak heater output
- Rising engine temperature if coolant is missing
- Likely causes
- LikelyLow coolant level or air trapped after service, so the impeller runs dry
- PossibleImpeller loose or damaged, so the motor turns without load
- PossibleFaulty pump electronics or speed feedback signal
- RareFlow path blocked by a stuck valve, changing the pump load
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €20 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.