P0A5E: Drive Motor A Phase U Current Low

P0A5E means too little current flows, or is sensed, in phase U of drive motor A, the classic sign of an open phase. GM describes the check for the motor control processor of the 2016 Chevrolet Volt and in its 2018 hybrid tables: with the inverter in normal PWM above 50 V and a squared current command above 900 A2 (2016) or 4,900 A2 (2018), the absolute U current is sampled while the rotor is within 30 degrees of the U phase axis; below 9 A for 0.4 s of a 0.6 s window, P0A5E sets as Type A, MIL on the first trip. Each phase is tested in turn as the rotor turns. A Caterpillar patent likewise spots a dead sensor by a phase reading near zero. P0A61 and P0A64 are phases V and W, P0A5F the high side, P0A5D the general U code.

Symptoms

• MIL and propulsion system warning
• Rough or reduced electric drive, possible engine-only operation

Most likely causes

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

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 P0A5E means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• A: Hybrid or air and fuel
• 5E: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0A5E?

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 P0A5E?

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

Related codes

• P0A5DDrive Motor A Phase U Current
• P0A5FDrive Motor A Phase U Current High
• P0A61Drive Motor A Phase V Current Low
• P0A64Drive Motor A Phase W Current Low
• P0A67Drive Motor B 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.