P0B06 code meaning
Electric/Auxiliary Transmission Fluid Pump Motor Phase W Current
Powertrain system Generic code P0Bxx codes Check engine light
What P0B06 means
P0B06 is the general current fault for phase W of the auxiliary transmission fluid pump motor. No manufacturer publishes a monitor description for this exact code. GM covers phase W in its Volt, ELR and CT6 calibrations with the low-side code P0B07 and treats overcurrent on any phase as P0C28. CARB requires hybrid and transmission components whose failure affects emissions or other monitors to be checked for circuit faults and rationality, which is why manufacturers can use the general code for implausible readings. The Hitachi sub-oil pump patent describes a sinusoidal drive whose W current is calculated from a single bus shunt, so wiring, sensing and the power stage are all suspects. The pump stops and auto-stop is blocked. P0B07/P0B08 are the low and high variants, P0B00 and P0B03 phases U and V.
P0B06 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 6 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0B06
- MIL or transmission/hybrid warning
- Engine keeps running at stops, no auto-stop
Common causes of P0B06
- Most likelyPoor contact in the phase W lead or pump connector
- PossibleCurrent sensing in the pump inverter faulty
- PossiblePhase W power stage in the pump control module faulty
- Less likelyWinding fault in phase W of the pump motor
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Aux trans pump motor phase wAux trans pump control moduleWiring harness
What each part of P0B06 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| B | Area: hybrid propulsion. |
| 06 | The exact fault in that area. |
What to do next
- Note P0B06 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0B06
What does P0B06 mean?
P0B06 means "Electric/Auxiliary Transmission Fluid Pump Motor Phase W Current". P0B06 is the general current fault for phase W of the auxiliary transmission fluid pump motor. It is a generic code, so it means the same on every make.
Is it safe to drive with P0B06?
Drive gently and only to a workshop. With P0B06 the car can go into limp mode (reduced power) to protect itself.
Will P0B06 fail an emissions test?
Yes, it can. P0B06 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0B06 to fix?
Difficulty: hard. A typical repair takes 1 to 6 hours of work. This is a job for a workshop.
Will P0B06 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.