Code result
P28ED
Electric/Auxiliary Transmission Fluid Pump B Overspeed
High severity
What it means
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?
No — stop driving
This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly.
Most likely causes
Pump impeller damage - load lost
highOne of the most commonly reported causes for this code — check this first.
Aerated fluid - reduced load
mediumA plausible cause — test and verify before replacing parts.
Related help
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