P0C07: Drive Motor A Phase U-V-W Circuit High

P0C07 is the high member of the drive motor A phase circuit group: a U, V or W phase line reads higher than it should, most likely through a short to the positive high-voltage rail or a power switch that stays on. Its siblings are P0C05 for an open phase and P0C06 for a phase pulled low. No manufacturer documents P0C07 publicly; among these three, GM uses only P0C05, which watches for missing phase current. CARB requires circuit monitoring of hybrid input and output components. Because a stuck high phase drives uncontrolled current, the inverter normally disables motor A at once. The driver sees a warning lamp and loses some or all electric propulsion until the shorted part is replaced.

Symptoms

• Immediate shutdown of electric drive with warning lamp
• Reduced performance or engine-only operation

Most likely causes

• Shorted high-side power switch in the motor A inverter
• Phase cable shorted to the positive high-voltage path
• Faulty gate driver holding a switch on

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 P0C07 means

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

Frequently asked questions

Can I keep driving with code P0C07?

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 P0C07?

The most common causes are: shorted high-side power switch in the motor A inverter; phase cable shorted to the positive high-voltage path; faulty gate driver holding a switch on.

Related codes

• P0C05Drive Motor A Phase U-V-W Circuit/Open
• P0C06Drive Motor A Phase U-V-W Circuit Low
• P0C0ADrive Motor B Phase U-V-W Circuit High
• P0C01Drive Motor A Current High
• P0BFDDrive Motor A Phase U-V-W Current Sensor Correlation

Sources

• law.cornell.edu: 13 CCR 1968.2
• 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.