Before returning the high-voltage battery (Fig. 6) of the 2023-2025 LYRIQ; 2024-2025 Blazer EV, Equinox EV, Silverado EV, Sierra EV; 2022-2025 HUMMER EVs; and 2022-2025 BrightDrop models, there are a number of criteria to follow in order to determine the internal stability of the battery and the proper core return shipping method.
Fig. 6
If the vehicle has any of the following DTCs set, there are several additional checks that need to be performed to help determine the proper repair instructions to follow.
Current DTCs
- P0AA6 (Hybrid/EV Battery Voltage System Isolation Lost)
- U359E (Hybrid/Electric Vehicle Battery Pack 2 Isolation Fault)
- P0AE3 (Hybrid/Electric Vehicle Battery Precharge Contactor Circuit Stuck Open)
- P0C78 (Hybrid/Electric Vehicle Battery System Precharge Time Too Long)
- U1666 (Lost Communication with Hybrid/Electric Vehicle Battery Pack Communication Module on Private Bus 1)
- U1667 (Lost Communication with Hybrid/Electric Vehicle Battery Pack Communication Module on Private Bus 3)
- U2426 (Hybrid/Electric Vehicle Battery Pack Communication Module Lost Communication with Hybrid/Electric Vehicle Battery Cut-Off Actuator on Private CAN Bus 1)
- U2427 (Hybrid/Electric Vehicle Battery Pack Communication Module Lost Communication with Hybrid/Electric Vehicle Battery Cut-Off Actuator on Private CAN Bus 2)
- U2BFC (Hybrid/Electric Vehicle High Voltage Battery Pack Thermal Event Damage)
- P1C34 (Hybrid/EV Battery Pack Current Sensor – Temperature Sensor Circuit Low)
- U35B5 (Hybrid/Electric Vehicle Battery Monitoring Module Performance)
History DTCs
- P0AA6 (Hybrid/EV Battery Voltage System Isolation Lost)
- U359E (Hybrid/Electric Vehicle Battery Pack 2 Isolation Fault)
All repairs must be documented in a Technical Assistance Center (TAC) case. Refer to Bulletin #23-NA-151 for complete details. All information in the bulletin must be completed as outlined.
The information presented in the bulletin addresses high-voltage battery stability, the potential for loss of isolation, vehicle handling based on the condition of the high-voltage battery and battery pack return shipping requirements.
Follow All Checklist Guidelines
Be sure to follow the Hybrid/EV Stability Checklist in the bulletin that covers vehicle inspection guidelines and high-voltage battery removal inspection and analysis. These steps, which will help determine the correct storage and shipping procedures, include:
- Inspecting the coolant level. (Fig. 7)
Fig. 7
- Checking the GDS2 session log for Hybrid/EV Vehicle Battery Pack Thermal Stability Data.
- Moving the vehicle to a stable location.
- Starting a TAC case.
- Disabling high voltage at the A4 Hybrid/EV Battery Pack.
- Inspecting all battery pack HV connectors and headers. (Fig. 8)
Fig. 8
- Removing the HV battery pressure equalizer vent and inspection plug and checking for moisture and coolant. (Fig. 9)
Fig. 9
- Performing the Hybrid Battery Pack Coolant Passage Leak Test.
Refer to Bulletin #23-NA-151 for more information.
Thanks to John Sauer
