OBD-II code · Powertrain (generic, extended)
P28EE Electric/Auxiliary Transmission Fluid Pump B Underspeed
The auxiliary transmission fluid pump B falls below the calibrated minimum speed for the commanded duty. Mechanical resistance high or supply voltage low.
Is it safe to drive with P28EE?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyPump mechanically binding
- PossibleSupply voltage low under 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
- P28EBShift Motor Position Not Learned
- P28ECShift Motor Position Sensor Exceeded Learning Limit
- P28EDElectric/Auxiliary Transmission Fluid Pump B Overspeed
- P28EFEngine Disconnect Clutch Actuator Performance/Stuck Off
- P28F0Engine Disconnect Clutch Actuator Stuck On
- P28F1Engine Disconnect Clutch Pressure Sensor Circuit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.