P0BFB code meaning
Drive Motor B Phase W Current Sensor Circuit Low
Powertrain system Generic code P0Bxx codes Check engine light
What P0BFB means
P0BFB indicates that the phase W current sensor of the motor B inverter delivers a signal below its valid range. GM's limits: below -800 A on the 2011 Volt (Type A, 4 of 6 samples at 10.4 ms), below -700 A on the 2012 and 2013 two-mode trucks (Type B, two trips) and below -700 A for 0.05 of 0.1 s in the 2016 tables or 0.1 of 0.15 s in a 2019 table (Type A, one trip). The threshold lies well outside any phase current motor B can carry, so the likely cause is a sensor output stuck near ground, a failed sensor or a supply fault on the sensor board. P0BFA covers a shifted zero, P0BFC the high side. While the code is active, motor B delivers reduced or no torque.
P0BFB at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 6 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0BFB
- Malfunction indicator lamp and hybrid warning
- Reduced power or no contribution from drive motor B
Common causes of P0BFB
- Most likelyFailed phase W current sensor in the motor B inverter
- PossibleSensor signal or supply pulled to ground on the sensor board
- Less likelyPoor contact at an internal or external inverter connector
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Drive motor b phase w current sensorWiring harnessHybrid control module
What each part of P0BFB 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. |
| FB | The exact fault in that area. |
What to do next
- Note P0BFB 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 P0BFB
What does P0BFB mean?
P0BFB means "Drive Motor B Phase W Current Sensor Circuit Low". P0BFB indicates that the phase W current sensor of the motor B inverter delivers a signal below its valid range. It is a generic code, so it means the same on every make.
Is it safe to drive with P0BFB?
Drive gently and only to a workshop. With P0BFB the car can go into limp mode (reduced power) to protect itself.
Will P0BFB fail an emissions test?
Yes, it can. P0BFB 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 P0BFB to fix?
Difficulty: workshop only. A typical repair takes 1 to 6 hours of work. This is a job for a workshop.
Will P0BFB clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.