P2DE9
Cold Start Engine Coolant Pump Underspeed
During cold start, the engine coolant pump runs below the calibrated minimum speed. Cold viscosity load too high or pump weak.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
Common causes
Ordered by how often each turns out to be the cause.
- Cold coolant viscosity too highCommon
- Pump output degradedPossible
Parts involved
- Engine Coolant Pump
P2DE9 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.