P25E9
Supercharger Disconnect Clutch Stuck Open
The clutch that engages the mechanical supercharger to the engine drive will not close. The supercharger stays disengaged so boost from this stage is unavailable, which limits torque and may also affect cooling pump drives shared with the same belt.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
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
Common causes
Ordered by how often each turns out to be the cause.
- Open electromagnetic clutch coilCommon
- Worn friction surfaces leave the air gap too large to attractPossible
- Corroded armature plate stuck openLess likely
Parts involved
- Supercharger Clutch
- Clutch Solenoid
- Clutch Pulley
P25E9 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.