P0C05: Drive Motor A Phase U-V-W Circuit/Open

P0C05 detects an open or missing phase between the inverter and drive motor A. GM checks each phase as the rotor passes its axis: if the peak phase axis current stays below 9 A while at least 23 A is commanded, with the rotor within 30 degrees of that axis and over 35 V on the inverter, about 200 failed samples set the code. It is Type A, one trip, on the Volt and two-mode trucks and Type B, two trips, on eAssist. Jeep lists it on the 2018/19 Wrangler eTorque with P0C01, curing it by software or a new motor generator unit. Volvo uses it in the rear axle inverter of 2020 to 2022 PHEVs and advises clearing it and test-driving before replacing parts. Expect reduced electric power.

Symptoms

• Propulsion system performance message or warning lamp
• Reduced electric drive power
• Loss of 12 V charging or noise from the motor generator on mild hybrids

Most likely causes

• Loose or open three-phase terminal between inverter and motor A
• Software fault, cured by update (Jeep TSB 08-144-23)
• Internal fault of the motor generator unit or open stator winding
• One-off event that does not return after clearing (Volvo TJ 36863)

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 continuity of the wire between the component and the control module.
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 P0C05 means

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

Frequently asked questions

Can I keep driving with code P0C05?

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 P0C05?

The most common causes are: loose or open three-phase terminal between inverter and motor A; software fault, cured by update (Jeep TSB 08-144-23); internal fault of the motor generator unit or open stator winding.

Related codes

• P0C06Drive Motor A Phase U-V-W Circuit Low
• P0C07Drive Motor A Phase U-V-W Circuit High
• P0C08Drive Motor B Phase U-V-W Circuit/Open
• P0C01Drive Motor A Current High
• P0BFDDrive Motor A Phase U-V-W Current Sensor Correlation
• P0BE5Drive Motor A Phase U Current Sensor Circuit
• P0BE9Drive Motor A Phase V Current Sensor Circuit
• P0BEDDrive Motor A Phase W Current Sensor Circuit

Sources

• gsi.ext.gm.com: 11OBDG01 HYBRID Diagnostics
• gsi.ext.gm.com: 12OBDG06 Hybrid Diagnostics
• gsi.ext.gm.com: 13OBDG05C Hybrid Diagnostics
• gsi.ext.gm.com: 16OBDG01 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.