Powertrain, generic · Hybrid propulsion

P0BF8 Drive Motor B Phase V Current Sensor Circuit High

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P0BF8 sets when the phase V current sensor of drive motor B reports more current than its valid range allows. GM uses above 800 A on the 2011 Volt with the PWM output disabled (Type A), above 700 A on the 2012 and 2013 two-mode trucks (Type B, two trips) 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, one trip). Such a reading while the inverter is not switching, or far above the overcurrent limit, isolates a sensor-side fault such as a signal shorted to the supply or a broken reference ground. It pairs with P0BF7 for the low side and P0BF6 for offset; real overcurrent appears as P0C04. Expect motor B to be derated and further inverter codes in memory.

Likely causes

Failed phase V 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

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 v current sensorwiring harnesshybrid control module

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