P28EEElectric/Auxiliary Transmission Fluid Pump B Underspeed
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P28EE is the reverse of P28ED: electric transmission fluid pump B does not reach the speed its controller asks for. The motor is fed, but something holds it back, such as very cold and thick fluid, a binding or worn pump, debris in the gears or a low supply voltage. When the speed falls to zero the matching code is the stall P277C rather than this one. No manufacturer documents P28EE publicly. Comparable logic exists for single pumps: on the 2016 Cadillac ELR GM sets P1E3A, Type A, when commanded minus actual speed exceeds 200 rpm while more than 6.8 Nm is requested, while under P0B0D Ford's 2019 plug-in hybrids react to a speed under 95 percent of command for 3 s. CARB requires functional checks. The car then keeps the engine running or limits electric driving.
- What you may notice
- Transmission warning or check engine light on
- Engine keeps running at stops, electric driving limited
- Delayed engagement after an automatic engine restart
- Likely causes
- LikelyPump binding, worn or contaminated with debris
- PossibleVery cold, aged or wrong transmission fluid
- PossibleLow supply voltage or high resistance in the pump feed
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.