OBD-II code · Powertrain (generic, extended)
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.
Is it safe to drive with P28ED?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyPump impeller damage - load lost
- PossibleAerated fluid - reduced load
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
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 2–7 h
- Emissions test
- Usually unaffected
- Parts involved
- Aux Transmission Pump B, Transmission Fluid
Related codes
- P28EAShift Motor Position Sensor Circuit Range/Performance
- P28EBShift Motor Position Not Learned
- P28ECShift Motor Position Sensor Exceeded Learning Limit
- P28EEElectric/Auxiliary Transmission Fluid Pump B Underspeed
- P28EFEngine Disconnect Clutch Actuator Performance/Stuck Off
- P28F0Engine Disconnect Clutch Actuator Stuck On
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.