P2DF8Coolant Pump E 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
- P2DF8 means coolant pump E keeps turning, but slower than the module asked for. No manufacturer documents P2DF8 publicly. Ford's 2024 gasoline summary treats underspeed as fault type B2 of its pumps A and B, monitored continuously from 11 V over 5 seconds. GM's 2025 ECM tables show a concrete limit for the electric main pump (P2B85): the filtered gap between requested and reported speed must stay above a calibrated threshold for 8 of 10 seconds. Air can produce underspeed as well as overspeed: GM bulletin 24-NA-160 explains that on the Corvette E-Ray an air pocket made the battery coolant pump halt to protect itself, which its module logged as underspeed (P0E3C), and calls for bleeding first. Other causes are bearing wear, debris and low supply voltage. A rotor that does not turn at all is P2DF9.
- What you may notice
- Warning lamp on
- Insufficient cooling or heating of the served circuit
- Power reduction possible at high load
- Likely causes
- LikelyBearing wear or debris dragging on the rotor
- PossibleAir pocket causing the pump to slow or pause for self-protection
- PossibleVoltage drop in the pump feed or ground
- RareWeak pump motor or electronics
- 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: €30 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.