P0A67: Drive Motor B Phase U Current Low

P0A67 reports that phase U of drive motor B carries too little current at the moment it should peak, which GM interprets as an open circuit in that phase. In the 2016 Chevrolet Volt tables for motor control processor B the test runs while the rotor is within 30 degrees of the U axis, the inverter is above 50 V in normal PWM and the squared current command exceeds 900 A²; a peak below 9 A for 0.4 s within a 0.6 s window sets a Type A fault with MIL on the first trip. GM's 2018 tables shared by the Volt and the CT6 plug-in keep the test but raise the command threshold to 4,900 A². P0A68 is the high side, P0A6A and P0A6D are phases V and W, P0A5E the motor A counterpart. Motor B is disabled.

Symptoms

• MIL on the first trip and propulsion system warning
• Jerky or weak electric drive, reduced power

Most likely causes

• Open circuit in the phase U cable, connector or terminal of motor B
• Phase U switch of the motor B inverter not conducting
• Phase U current sensor stuck at zero
• Open winding of phase U in drive motor B

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 P0A67 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• A: Hybrid or air and fuel
• 67: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0A67?

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 P0A67?

The most common causes are: open circuit in the phase U cable, connector or terminal of motor B; phase U switch of the motor B inverter not conducting; phase U current sensor stuck at zero.

Related codes

• P0A66Drive Motor B Phase U Current
• P0A68Drive Motor B Phase U Current High
• P0A6ADrive Motor B Phase V Current Low
• P0A6DDrive Motor B Phase W Current Low
• P0A5EDrive Motor A Phase U Current Low

Sources

• gsi.ext.gm.com: 16OBDG01 Hybrid Diagnostics
• gsi.ext.gm.com: 18OBDG01 Hybrid Diagnostics
• patents.google.com: en

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.