Bulletin No.: PIP5957A
Published date: 02/29/2024

Preliminary Information
PIP5957A Service High Voltage with MIL and/or DTCs
Models
Brand:

Model:

Model Years:

VIN:
from

Engine:

to

Transmissions:

Cadillac

Lyriq

2023 - 2024

All

All

All

All

Chevrolet

Blazer EV

2024

All

All

All

All

Involved Region or Country North America
Some customers may comment the MIL is illuminated or Service High Voltage
Message displayed on the IPC and the vehicle could operate in a reduced power
mode.
Condition

Cause

A technician may nd any of the following DTCs U3620, U3621, U3622, U3623,
U3624, U3625, U3626, U3627, U3628, U3629, U362A, U362B, U362C, U362D, U362E,
U362F, U3630, U3631, U3632, U3633, U3634, U3635, U3636.
This could be related to cell voltage imbalance and calibration anomaly.

Correction:
1. With the vehicle in Service mode, use GDS2, verify U3620, U3621, U3622, U3623,
U3624, U3625, U3626, U3627, U3628, U3629, U362A, U362B, U362C, U362D, U362E,
U362F, U3630, U3631, U3632, U3633, U3634, U3635, U3636.
2. Program the BECM with the latest SPS Software Update.
3. Perform Secured Code Clear procedure:
a. Vehicle needs to be in service mode. (No Power steering)
b. With a scan tool, follow the navigation path:
Module Diagnostics - Select - K16 Battery Energy Control Module.
Configuration/Reset Function - Reset Function.
Reset Function: Hybrid/Electric Vehicle Battery Interface Control Module
Voltage Sensor Circuits High-Low.
c. Follow the GDS2 on-screen instructions to Clear the Secured High Voltage
DTC(s)/lockout.
d. Perform the K16 Battery Energy Control Module DTC code clear.
Disconnect Scan tool, Power OFF the vehicle, and shut all the doors to allow the Battery
Energy Control Module to enter sleep mode.
Note: Turning the vehicle OFF but maintaining scan tool to control module
communications will not allow the control module to enter sleep mode.
4. Wait at least 12 minutes with the vehicle in the prescribed condition so that the
modules may enter sleep mode.
5. With a scan tool make sure that the latched DTCs were really cleared by performing a
read DTC with GDS2.

If not, repeat steps to Clear the Secured High Voltage DTC(s)/lockout.
6. Record the Customers Charge level settings.
7. If necessary, deplete the HV Battery to below 50%.
8. Set the target charge level to 80% and charge vehicle using AC or DC fast charge.
9. Perform short test drive (5 to 10 miles) and allow the vehicle to rest/soak for minimum
4hrs or overnight.
10. Following rest/soak period, with Scan tool confirm the DTCs have not set again.
If DTCs sets again, or returns later, do not clear codes, program vehicle, or
disconnect 12v battery. Contact TAC by DCM or Phone Setting up a TAC case
referencing PIP5957 number.
11. Return charge level setting to customer preference.

Warranty Information
For vehicles repaired under the Bumper-to-Bumper coverage (Canada Base Warranty coverage), use the following
labor operation. Reference the Applicable Warranties section of Investigate Vehicle History (IVH) for coverage
information.
Labor Operation
*4086178
2810945

Description
Code Clear/Cycling procedure
Programming BECM

Labor Time
0.6 Hr.
Use published labor times

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

Version History
Version

2

Modi ed

01/19/2024 - Created on.
02/29/2024- Updated correction and warranty information.

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