EGR Cooler Coolant Pump Stuck On
The pump or its driver is stuck on - the pump runs continuously, even with the engine off, draining battery and bleeding heat from the engine.
Affected components
- Egr cooler coolant pump
Common causes
- High likelihood: Driver stage stuck on
- Low likelihood: Carbon or debris buildup preventing free movement
- Low likelihood: Component wear with age - mechanical play
Possible symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.