P0B0B code meaning
Electric/Auxiliary Transmission Fluid Pump A Motor Supply Voltage Circuit High
Powertrain system Generic code P0Bxx codes Check engine light
What P0B0B means
P0B0B reports a supply voltage at the motor of auxiliary pump A that is above the expected range. Subaru documents it on the 2014-15 XV Crosstrek Hybrid (bulletin 16-94-15R), together with P172A: a leaking O-ring at the electric oil pump relief valve can let CVT fluid into the pump motor. The check removes the three U, V and W cables at the oil pump inverter and reads AC voltage across them with the engine held at 1800 rpm in Park; 0.5 V or more means the drive motor and case assembly with the damaged seal must be replaced, less means the cause lies elsewhere. Subaru adds that P0C79, drive motor inverter voltage too high, appears only together with these codes and does not mean the inverter is faulty. P0B09 and P0B0A are the open and low variants.
P0B0B at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 12 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0B0B
- Warning lamp on, hybrid or CVT function restricted
- Possibly P0C79 stored at the same time
Common causes of P0B0B
- Most likelyCVT fluid entering the pump motor via a leaking relief valve O-ring (Subaru XV Crosstrek Hybrid)
- PossibleSupply circuit shorted to a higher voltage source
- Less likelyOil pump inverter or its voltage sensing faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Aux trans pump a motorWiring harnessTCM
What each part of P0B0B 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. |
| 0B | The exact fault in that area. |
What to do next
- Note P0B0B 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 P0B0B
What does P0B0B mean?
P0B0B means "Electric/Auxiliary Transmission Fluid Pump A Motor Supply Voltage Circuit High". P0B0B reports a supply voltage at the motor of auxiliary pump A that is above the expected range. It is a generic code, so it means the same on every make.
Is it safe to drive with P0B0B?
Drive gently and only to a workshop. With P0B0B the car can go into limp mode (reduced power) to protect itself.
Will P0B0B fail an emissions test?
Yes, it can. P0B0B 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 P0B0B to fix?
Difficulty: workshop only. A typical repair takes 1 to 12 hours of work. This is a job for a workshop.
Will P0B0B clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.