Bulletin No.: 23-NA-151

Service Bulletin

Date: June, 2024

INFORMATION
Hybrid/EV Battery, High Priority DTCs, Potential Loss of Isolation, Vehicle
Handling and RESS Shipping Requirements

Subject:

Brand:

Model:

Model Year:
from

BrightDrop
Cadillac

Zevo 600

2022

Zevo 400

2024

LYRIQ

2023

Blazer EV
Chevrolet

Equinox EV

2024

VIN:
to

Engine:

from

2024

—

Transmission:

to

—

All

All

Silverado EV
GMC

HUMMER EV

2022

HUMMER EV SUV

2024

Involved Region or Country

North America, Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Egypt, Europe,
Cadillac Korea (South Korea), GM Korea Company, Japan, Palestine, Israel, Middle
East, Kazakhstan, Australia/New Zealand.

Information

This bulletin and criteria within are to determine the internal state of the High Voltage Battery and core return shipping method.
If a vehicle arrives with any of the DTCs on the list, additional checks need to occur to
give proper direction on vehicle storage and repair instructions and must be documented in a TAC Case.
In the event a High Voltage Battery needs replacement, perform the service instruction
steps (1-9) if any of the following DTCs listed are set as current before starting a TAC
case for High Voltage Battery order authorization.
DTCs: P0AA6, P0AA7, U359E, U2220, U2221, U2222, U2223, U2224, U2225, U2226,
U2227, U2228, U2229, U222A, U222B, U222C, U222D, U222E, U222F, U2230, U2231,
U2232, U2233, U2234, U2235, U2236, U2237, U1666, U1667, U2426, U2427, U2BFC,
P1C34, U35B5.

Service Procedure
Warning: Never leave a vehicle or battery pack with
a high-risk DTC indoors overnight, all work should
be completed during normal business hours.
Danger: Failure to use the proper Personal
Protective Equipment and failure to carefully follow
these procedures may result in serious injury or
death.
Important: Service agents must comply with all
International, Federal, State, Provincial, and/or
Local laws applicable to the activities it performs
under this bulletin, including but not limited to
handling, deploying, preparing, classifying,
packaging, marking, labeling, and shipping
dangerous goods. In the event of a conflict
between the procedures set forth in this bulletin

Copyright 2024 General Motors. All Rights Reserved.

and the laws that apply to your dealership, you
must follow those applicable laws.
Important: This technical service bulletin (TSB) can
only be completed by certified repair facilities who have
met all specific training, tool and equipment requirements pertaining to the vehicle Brand and Model
serviced. Repairs must be performed by a technician
who has successfully completed the required training.
Important: Please review the data thoroughly. GM will
not authorize core return shipment requests without
proper review, which could lead to non-return core fee
charges. It is essential to complete all steps outlined
below and provide data to TAC for review and further
direction, to avoid delays in the pick-up the high voltage
battery core and prevent any duplication of work.
Note: Steps outlined below can also be found on
Center of Learning Course # 59520.14V.

Page 2

June, 2024

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1. Verify any of the following conditions: DTCs
U2BFC or P1C34 are set as current or history, the
customer heard abnormal noises, or if the vehicle
experienced a loss of propulsion while driving? If
yes, report results to TAC as additional review will
be necessary to help determine stability.
Notes/Findings:
2. Provide a clear and thorough description of the
concern from the customer. Was the vehicle towed
because of a no start concern or loss of
propulsion?
Notes/Findings:
3. Verify any of the following DTCs are set as current;
P0AA6, P0AA7, U359E, U2220, U2221, U2222,
U2223, U2224, U2225, U2226, U2227, U2228,
U2229, U222A, U222B, U222C, U222D, U222E,
U222F, U2230, U2231, U2232, U2233, U2234,
U2235, U2236, U2237, U1666, U1667, U2426,
U2427. Verify if DTC U35B5 set as current or
history.
Notes/Findings:
4. Visually inspect and document the coolant level in
the high-voltage battery surge tank (Fig 1) and
document via photo. Inform TAC if coolant has
previously been added.
Notes/Findings:
Note: The Data in steps 5-7 can also be found in K16 –
Battery Energy Control Module -> Data Display ->
Hybrid/Electric Vehicle Battery Pack Thermal Stability
Data.
5. Observe and record the Battery Energy Control
Module parameter(s); K16 – Battery Energy
Control Module -> Data Display -> High Voltage
Isolation Data -> Most Recent Isolation Resistance
– Pack & (Pack 2 if equipped).
Notes/Findings:
6. Observe and record the Battery Energy Control
Module parameter(s); K16 – Battery Energy

Bulletin No.: 23-NA-151
Control Module -> Data Display -> Hybrid/Electric
Vehicle Battery Pack Temperature Data -> Hybrid/
Electric Vehicle Battery Pack Thermal Event Gas
Sensor and Hybrid/Electric Vehicle Battery Pack
Thermal Event Gas Sensor 2 in PPM (Parts Per
Million).
Notes/Findings:

7. Observe and record the Battery Energy Control
Module parameter(s); K16 – Battery Energy
Control Module -> Data Display -> Hybrid/Electric
Vehicle Battery Module Temperature Data ->
Hybrid/Electric Vehicle Battery Interface Control
Module 1 thru Module 24 (if equipped).
Notes/Findings:
Note: Record Top 3 Maximum Value or if all Similar
provide average temperature.
8. Start a TAC case and upload session log per
Document ID: 6385557 / PIP4902 and reference
this bulletin. Additionally, provide any previous
diagnosis work performed based on the DTC(s) set
or inability to collect the data.
Notes/Findings:
9. Move Vehicle to stable location to store vehicle
while waiting direction to repair. Document via
photo and upload to the TAC case. The recommended method for moving the vehicle would be
with HVSL pulled, Service Mode in neutral until
directed otherwise.
Note: Additional information or steps may be requested
based on the information provided from steps 1-9 listed
above. If instructed by TAC, perform the following steps
at time of High Voltage Battery replacement. Do NOT
submit a core pickup request unless given approval by
TAC.
10. Follow SI Procedure for RESS removal, Hybrid/
Electric Vehicle Battery Pack Removal and Installation.
11. After High Voltage Battery removal, inspect the
High Voltage Connectors at the High Voltage
Battery for corrosion, moisture, and/or soot. (Fig 2)
Take photos of the vehicle side HV connectors and
High Voltage Battery connection headers. Attach
photos to TAC Case. Refer to the SI Procedure for
High Voltage System Inspection.
Notes/Findings:
Note: If corrosion or moisture is observed, stop all work
and call TAC.
12. After High Voltage Battery removal, heck for High
Voltage at the Hybrid/Electric Vehicle Battery Pack
X1 through X7 (as equipped) by following High
Voltage Disabling – High Voltage Disable Confirmation Table – A4 Hybrid/EV Battery Pack in
Service Information.
Notes/Findings:
Note: If more than 3V is found, stop all work and call
TAC.

Bulletin No.: 23-NA-151

June, 2024

13. After High Voltage Battery removal, remove the
High Voltage Battery Pressure Equalizer Vent
Deflector(s) and/or Battery Inspection plug (if
equipped) (Fig 3). Using a cotton swab or paper
towel to swab inside the enclosure for moisture or
coolant. Take photos and attach to TAC case.
Notes/Findings:
Note: If fluid is observed, stop all work and call TAC.
14. Evacuate residual coolant from the High Voltage
Battery. Refer to the SI Procedure for Hybrid/
Electric Vehicle Battery Pack Replacement and
Shipping Preparation.
Notes/Findings:
Note: If unable to remove coolant from the
High Voltage Battery, stop all work, and call TAC.
15. Vacuum test the High Voltage Battery coolant
circuit. See Hybrid Battery Pack Coolant Passage
Leak Test. Attach photos to the TAC case.

Page 3
Notes/Findings:

Note: If the High Voltage Battery coolant circuit does
not hold vacuum, stop all work, and call TAC.
16. Pressure test the High Voltage Battery coolant
circuit (Only complete if passes vacuum test). See
Hybrid Battery Pack Coolant Passage Leak Test .
Attach photos to the TAC case.
Notes/Findings:
Note: If the High Voltage Battery coolant circuit does
not hold pressure, stop all work, and call TAC.
17. Place the High Voltage Battery in the provided
DDR Crate & move to stable location outdoors:
away from buildings, vehicles, and foot traffic.
Cover DDR crate with a tarp to protect from the
elements while awaiting further direction. Take
picture of crate and location and upload into TAC
Case." Report results to TAC for Engineering
review.

Figure 1

6522019

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Figure 2 Soot Examples

June, 2024

Bulletin No.: 23-NA-151

6654567

6654571

Bulletin No.: 23-NA-151

Figure 3 Liquid and Moisture
Examples

June, 2024

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6654576

6654583

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June, 2024

Bulletin No.: 23-NA-151

Other Examples

6522018

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

Description

Labor Time

5080398*

Hybrid/EV Battery Inspection & Transportability
Assessment

1.0 hr

*This is a unique Labor Operation for bulletin use only.
Version

6

Modified

Released September 05, 2023
Revised October 17, 2023 – Updated Model Years, Added Steps 8-12 and added Warranty Information.
Revised January 16, 2024 – Added Illustrations, Updated Steps, 2022 Model Year Zevo
600 and 2024 Zevo 400.
Revised March 14, 2024 – Added Europe and Updated information throughout the entire
bulletin.
Revised May 23, 2024 – Added Equinox EV model, updated Involved Region or Country
and multiple steps under Service Procedure.
Revised June 04, 2024 – Added Warning and Adjusted Step 17.

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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