Bulletin No.: PIP5957
Published date: 01/19/2024

Preliminary Information
PIP5957 Service High Voltage with MIL and/or DTCs
Models
Brand:

Model:

VIN:

Model Years:

from

Engine:

to

Transmissions:

Cadillac

Lyriq

2023 - 2024

All

All

All

All

Chevrolet

Blazer

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.

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. Perform Secured Code Clear procedure:
a. Vehicle needs to be in service mode.
b. With a scan tool, follow the navigation path:
i. Module Diagnostics - Select - K16 Battery Energy Control Module
ii. Con guration/Reset Function - Reset Function
iii. 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
3. 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
a. 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 con rm the DTCs have not set again
a. 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 PIP597 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

Description
Code Clear/Cycling procedure
*This is a unique Labor Operation for Bulletin use only.

Version History
Version
Modi ed

1
01/19/2024 - Created on.

Labor Time
0.6 Hr.

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