Bulletin No.: PIP6021C

Service Bulletin

Date: June, 2026

PRELIMINARY INFORMATION
Subject:

Brand:

MIL Illuminated or Service High Voltage Message Displayed on IPC; Potential
12V Battery Discharge
Model:

Model Year:
from

VIN:
to

from

Engine:

Transmission:

to

Cadillac

CELESTIQ

2025 - 2026

All

All

All

All

Cadillac

LYRIQ

2023 - 2026

All

All

All

All

Cadillac

OPTIQ

2025 - 2026

All

All

All

All

Cadillac

VISTIQ

2026

All

All

All

All

Chevrolet

Blazer EV

2024 - 2026

All

All

All

All

Chevrolet

Equinox EV

2024 - 2026

All

All

All

All

Involved Region or Country

North America

Condition

Some customers may comment the MIL is illuminated or Service High Voltage Message displayed on the IPC and the 12V battery might be discharged.
Technician may find “Any” of the following DTCs; P2C8A, P2C8B, U3577, U3578, U3579,
U357A, U357B, U357C, U357D, U357E, U357F, U3580, U35AF set as HISTORY.

Cause

A potential software anomaly attributed to perceived CMU (cell monitoring unit)
performance issues, may be present that will be fixed in a future OTA update.

Correction
Note: Follow Service Information Diagnostics for any of these DTC(s)/concerns first, Before the CMU Performance
code(s) included in this PI
Note: Updated Software and Calibrations will be released at a later date in the form of an OTA update or Service
Programing. Please inform the customer to accept any future OTA updates for their vehicle.
Service Procedure:
1. Verify the vehicle has “Any” of the following DTCs set; P2C8A, P2C8B, U3577, U3578, U3579, U357A, U357B,
U357C, U357D, U357E, U357F, U3580, and U35AF set as HISTORY.
2. Perform a Service Programming System (SPS2) Hybrid/EV Battery Data Retrieval
3. Program the K16 Battery Energy Control Module (BECM) through Vehicle Wide Programming (VWP) with the
most recent software via SPS2
Note: The vehicle may have the latest K16 Battery Energy Control Module Software and Calibrations. This will
result in a “SKIP” message while programming. Record and continue to step 4 of this procedure.
4. After programming through VWP, perform the Manual Reset process
5. Verify DTCs have not reset with GDS2
6. Follow the remaining on-screen instructions until completion and receive the Warranty Claim Code (WCC)
7. Record the Warranty Claim Code (WCC) on your Repair Order

Copyright 2026 General Motors. All Rights Reserved.

Page 2

June, 2026

Bulletin No.: PIP6021C

*SPS2 Hybrid/EV Battery Data Retrieval
1. Access the Service Programming System (SPS2) and follow the on-screen instructions.
2. Select Controller: K16 Battery Energy Control Module (BECM)
3. Select Function: Hybrid/ EV Battery Data Retrieval
Note: Although similar, the Hybrid/EV Battery Data Retrieval (under K16 Battery Energy Control Module) is not the
same as the Z4 - (Vehicle Capture of Module Identification Data) option in SPS2
4. Select Programming Type: Normal
5. Select the “Next” button at the bottom right of the screen.
6. Follow the remaining on-screen instructions until completion and receiving the Warranty Claim Code (WCC)
7. Record the Warranty Claim Code (WCC)on your Repair Order
Manual Reset Process:
A. Perform the Battery Negative Cable Disconnection and Connection procedure outlined in Service Information.
Warning: Always ensure the Battery Maintenance Mode is inactive before disconnecting the 12-volt battery.
This mode can be active with the ignition off, regardless of whether the vehicle charging cord is plugged in
or not. When this mode is active, the on-board high voltage battery charger will energize the 12-volt battery
cables and charge the 12-volt battery. Disconnecting the battery cables while this mode is active may
result in an electrical shock or a burn from hot battery cable leads.
B. Wait 15 mins, then reconnect the 12v following the Battery Negative Cable Disconnection and Connection
procedure outlined in Service Information.
C. Place the vehicle in Propulsion “Ready” mode for 10 seconds, (has power-steering) then turn the vehicle “OFF”
and remove the keyless transmitter from the vehicle and place the transmitter in a safe location approximately 10 ft
away. Wait 15 mins.
D. Repeat Manual Reset Process steps A-C a total of 2 times.
E. Place the vehicle in Service mode (No power-steering) then use GDS2 and clear all DTCs.
F. Charge the 12V battery
CMU Performance DTC Run Criteria:
1. Place the vehicle in Propulsion "Ready" mode for 10 mins.
2. Shift to Drive and back to park.
3. Turn the vehicle "OFF" and remove the keyless transmitter from the vehicle and place the transmitter in a safe
location approximately 10 ft or more away from the vehicle.
4. Wait 15 mins.
5. Place the vehicle in Propulsion "Ready" mode for 10 mins.
6. Verify DTCs have not reset with GDS2

Bulletin No.: PIP6021C

June, 2026

Page 3

Warranty Information
For vehicles repaired under the Powertrain coverage, use the following labor operation. Reference the Applicable
Warranties section of Investigate Vehicle History (IVH) for coverage information.
Labor
Operation

Description

Labor Time

5086068*

Hybrid/Electric Battery
1.5 Hrs.
Interface & Comm Module
Performance Manual Reset

Add Time

K16 Battery Energy Control Use
Module Program
published
time

Add Time

12v battery charging and
testing

Use
published
time

Add Time (as
req)

Hybrid/EV Battery Data
Retrieval

0.5 Hr.

*This is a unique Labor Operation for Bulletin use only.

Version

4

Modified

11/01/2024 - Created on.
04/29/2025- Updated Models and years.
10/30/2025- Updated language to reflect procedure that include 1 to all codes that can
set, along with update model years.
06/18/2026 Updated verbiage to reflect the 15 min wait time needed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job
properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.

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