Powertrain, generic · Hybrid propulsion

P0BFC Drive Motor B Phase W Current Sensor Circuit High

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P0BFC is the signal-high fault of the phase W current sensor in the motor B inverter. GM sets it above 800 A on the 2011 Volt (Type A, one trip), above 700 A on the 2012 and 2013 two-mode trucks (Type B, two trips, 10 of 15 samples) and above 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). A reading this high with no matching battery current indicates the sensor, its supply or an open reference instead of actual current; true phase overcurrent of motor B is logged as P0C04, and the plausibility of all three phases together as P0BFE. With P0BFC stored the inverter derates motor B, and the hybrid system leans more on the engine and motor A.

Likely causes

Failed phase W current sensor in the motor B inverter

Sensor signal shorted to the sensor supply voltage or open reference ground

Poor contact at an internal or external inverter connector

Symptoms

Malfunction indicator lamp and hybrid warning
Reduced power from drive motor B
Engine runs more often because electric drive is limited

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€150–4,000

Time1–6 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

drive motor b phase w current sensorwiring harnesshybrid control module

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.