P0BF8: Drive Motor B Phase V Current Sensor Circuit High

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.

Symptoms

• Malfunction indicator lamp and hybrid warning
• Reduced power from drive motor B

Most 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

What to check, in order

Start with the simplest. You can tick off each step.

1. Read the codes with a hybrid-compatible scanner and write down the freeze frame data
2. Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
3. Make sure the battery cooling air intake is clean
4. Check the 12 V auxiliary battery, which can also trigger warnings
5. Leave any high-voltage measurements to a specialized repair shop

Good to know

• It can trigger limp mode.
• It affects emissions.

What each character of P0BF8 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• B: Subsystem depends on the code range
• F8: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0BF8?

If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.

What causes code P0BF8?

The most common causes are: 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.

Related codes

• P0BF7Drive Motor B Phase V Current Sensor Circuit Low
• P0BF5Drive Motor B Phase V Current Sensor Circuit
• P0BF6Drive Motor B Phase V Current Sensor Circuit Range/Performance
• P0BF4Drive Motor B Phase U Current Sensor Circuit High
• P0BFCDrive Motor B Phase W Current Sensor Circuit High
• P0BECDrive Motor A Phase V Current Sensor Circuit High
• P0BFEDrive Motor B Phase U-V-W Current Sensor Correlation
• P0C04Drive Motor B Current High

Sources

• gsi.ext.gm.com: 19OBDG01 Hybrid Diagnostics
• gsi.ext.gm.com: 16OBDG02 Hybrid Diagnostics
• gsi.ext.gm.com: 11OBDG01 HYBRID Diagnostics
• gsi.ext.gm.com: 12OBDG06 Hybrid Diagnostics

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.