Engine Coolant Pump Clutch Stuck On
The coolant pump clutch remains engaged when commanded off. Pump runs continuously, slowing warm-up and increasing parasitic load.
Affected components
- Coolant pump clutch
Common causes
- High likelihood: Armature plate seized to the pulley face
- Medium likelihood: Driver stuck on keeps clutch energised
- Low likelihood: Carbon or debris buildup preventing free movement
Possible symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
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.