P0B04
Electric/Auxiliary Transmission Fluid Pump Motor Phase V Current Low
The phase V current of the auxiliary transmission fluid pump motor reports a current low fault. Pump phase commutation impaired.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
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
Common causes
Ordered by how often each turns out to be the cause.
- Phase winding partially openCommon
- Current sensor offset driftedPossible
Parts involved
- Aux Trans Pump Motor Phase V
- Wiring Harness
- TCM
P0B04 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.