P0B01Electric/Auxiliary Transmission Fluid Pump Motor Phase U Current Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0B01 means the pump inverter sees almost no current in phase U of the auxiliary fluid pump motor, typically an open phase. GM documents the check for the Volt motor control processor (2016) and its hybrid tables of 2018 and 2019: with the drive state in Run, the inverter in normal PWM above 50 V and a squared current command above 5 A2 (2016) or 14.97 A2 (2018), the peak current on the U axis is compared while the rotor is within 30 degrees of it; below 1 A for 0.4 s of a 0.6 s window, the code sets as Type A, MIL on the first trip. On the 2014-15 Chevrolet Spark EV, GM bulletin PI1433 links P0B01, P0B04 or P0B07, Service Vehicle Soon and reduced propulsion to an unlatched pump connector. P0B04/P0B07 are phases V and W, P0B02 the high side.
- What you may notice
- Service Vehicle Soon light and MIL
- Propulsion Power Reduced or Vehicle Speed Limited message
- Likely causes
- LikelyPump motor connector not fully seated or latched (Chevrolet Spark EV)
- PossibleOpen circuit in the phase U lead or terminal of the pump motor cable
- PossiblePhase U switch in the pump inverter not conducting
- RareOpen winding of phase U in the pump motor
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.