P0B01: Electric/Auxiliary Transmission Fluid Pump Motor Phase U Current Low
What to do
As P0B00 — the symptoms show up at rest rather than on the move, so describe what happens pulling away from a stop.
What this code means
Phase U of the auxiliary pump motor is drawing less current than the commanded speed calls for.
Low is the direction of resistance and gaps — a terminal losing tension, a connector corroding, a winding developing an open. The family's argument, including why this pump exists and why the fault hides while the engine runs, is at P0B00.
Likely causes
Start here
- Corroded or loose connector · easy
Less common
- Faulty auxiliary transmission fluid pump · specialist
- Damaged transmission wiring harness · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
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