P0A6D: Drive Motor B Phase W Current Low

P0A6D completes GM's set of open-phase tests for drive motor B with phase W. Because each phase is only judged while the rotor sits within 30 degrees of its own axis, the code points to W alone rather than to the motor as a whole. GM's tables for the 2016 Volt require a running drive, more than 50 V on the inverter in normal PWM and a squared current command above 900 A²; the 2018 tables for Volt and CT6 use 4,900 A². If the W peak stays under 9 A for 0.4 s within 0.6 s, the Type A fault turns on the MIL after one trip. Typical findings are an interrupted W lead or terminal, a non-conducting switch or a sensor reading zero. P0A6E is the high side, P0A67 and P0A6A phases U and V, P0A64 the motor A test.

Symptoms

• MIL on the first trip with propulsion warning
• Rough or reduced electric drive

Most likely causes

• Phase W lead or terminal of motor B interrupted
• Phase W switch of the inverter not conducting
• Phase W current sensor stuck at zero
• Open phase W winding in 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 P0A6D means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• A: Hybrid or air and fuel
• 6D: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0A6D?

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 P0A6D?

The most common causes are: phase W lead or terminal of motor B interrupted; phase W switch of the inverter not conducting; phase W current sensor stuck at zero.

Related codes

• P0A6CDrive Motor B Phase W Current
• P0A6EDrive Motor B Phase W Current High
• P0A67Drive Motor B Phase U Current Low
• P0A6ADrive Motor B Phase V Current Low
• P0A64Drive Motor A Phase W Current Low

Sources

• gsi.ext.gm.com: 16OBDG01 Hybrid Diagnostics
• gsi.ext.gm.com: 18OBDG01 Hybrid Diagnostics
• gsi.ext.gm.com: 16OBDG02 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.