Powertrain
generic / SAE
P28ED
Electric/Auxiliary Transmission Fluid Pump B Overspeed
The auxiliary transmission fluid pump B exceeds the calibrated maximum speed for the commanded duty. Mechanical load on the pump unexpectedly low.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number8 / ED
Possible causes
- Pump impeller damage - load lost high
- Aerated fluid - reduced load medium
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
Inspection / repair
- Difficulty: hard
- DIY: shop recommended
- Estimated cost: 400–1800 €
- Estimated time: 2–7 h
- Component: aux transmission pump b
- Component: transmission fluid
- MIL / check engine light
- limp mode possible
Sources
References
sae:J2012