Powertrain, generic · Hybrid propulsion

P0BEF Drive Motor A Phase W Current Sensor Circuit Low

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P0BEF indicates that the phase W current sensor of the motor A inverter delivers a signal below its valid range. GM's limits: below -700 A for 0.05 of 0.1 s (2016 tables) or 0.1 of 0.15 s (2019), Type A; below -800 A, Type A, on the 2011 Volt; below -700 A, Type B, on the 2012 two-mode trucks; below -440 A, Type B, two trips, in the BAS Plus (eAssist) table. These readings lie far outside real phase currents, so a sensor output stuck near ground, a failed sensor or a supply fault is the likely cause. In the eAssist system this fault puts current control into a mode that ignores the sensors, and it disables the U-V-W correlation check P0BFD, so motor A runs with reduced output.

Likely causes

Failed phase W current sensor inside the inverter

Sensor signal or supply pulled to ground on the sensor board

Poor contact at an internal or external inverter connector

Symptoms

Malfunction indicator lamp and hybrid warning
Reduced power or no assist from drive motor A

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 a phase w current sensorwiring harnesshybrid control module

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