U028A
Lost Communication With Transmission Fluid Pump Module B
The vehicle bus reports loss of communication with transmission fluid pump module B. Auxiliary ATF pumping during start/stop or hybrid coast cannot be commanded, which may delay shifts or impair cooling.
The vehicle bus reports loss of communication with transmission fluid pump module B. Auxiliary ATF pumping during start/stop or hybrid coast cannot be commanded, which may delay shifts or impair cooling.
Common causes
- high
Bus wiring open or shorted
One of the most commonly reported causes for this code — check this first.
Typical part cost: $220-2200
- medium
Module without power or ground
A plausible cause — test and verify before replacing parts.
Typical part cost: $220-2200
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First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
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Related codes
See related trouble codes
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Frequently asked questions
What does U028A mean?
U028A means "Lost Communication With Transmission Fluid Pump Module B". It is a generic OBD-II code that points to a fault in the network / communication.
What are the most common causes of U028A?
bus wiring open or shorted; module without power or ground; module failed — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly. Use the Wrenchify app for a full diagnosis specific to your vehicle.
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