P0BF3: Drive Motor B Phase U Current Sensor Circuit Low

P0BF3 is stored when the phase U current sensor of the motor B inverter reports a value below its valid range. GM converts the sensor voltage into amps and sets the code below -800 A on the 2011 Volt (Type A, 4 of 6 samples), 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). No real phase current of motor B reaches such values, so the reading reflects an electrical defect, typically a sensor output pulled toward ground or a dead sensor. The offset check P0BF2 covers a shifted zero instead. Motor B is then restricted or shut off.

Symptoms

• Malfunction indicator lamp and hybrid warning
• Reduced power or no contribution from drive motor B
• Possible shutdown of electric drive

Most likely causes

• Failed phase U current sensor in the motor B inverter
• Sensor signal or supply pulled to ground on the sensor board
• 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. With the connector unplugged, check whether the signal wire is making contact with ground.
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 P0BF3 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• B: Subsystem depends on the code range
• F3: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0BF3?

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 P0BF3?

The most common causes are: failed phase U current sensor in the motor B inverter; sensor signal or supply pulled to ground on the sensor board; poor contact at an internal or external inverter connector.

Related codes

• P0BF4Drive Motor B Phase U Current Sensor Circuit High
• P0BF1Drive Motor B Phase U Current Sensor Circuit
• P0BF2Drive Motor B Phase U Current Sensor Circuit Range/Performance
• P0BF7Drive Motor B Phase V Current Sensor Circuit Low
• P0BFBDrive Motor B Phase W Current Sensor Circuit Low
• P0BE7Drive Motor A Phase U Current Sensor Circuit Low
• P0BFEDrive Motor B Phase U-V-W Current Sensor Correlation

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.