NHTSA ID Number: 11023484
Manufacturer Communication Number: 23-NA-151
TSB/Document Date: 2025-10-02
Summary
This service bulletin and criteria within are to determine the internal state of the High Voltage Battery
and core return shipping method.
Bulletin No.: 23-NA-151
Service Bulletin
Date: May, 2025
INFORMATION
Subject:
Brand:
Hybrid/EV Battery Stability, High Priority DTCs, Potential Loss of Isolation,
Vehicle Handling and Battery Pack Return Shipping Requirements
Model:
Model Year:
from
BrightDrop
VIN:
to
from
EV600
2022
2022
Zevo 600
2023
2024
Zevo 400
2024
2024
CELESTIQ
2025
2025
LYRIQ
2023
2025
OPTIQ
2025
2025
Escalade IQ
2025
2026
Escalade IQL
2026
2026
VISTIQ
2026
2026
Blazer EV
2024
2025
Equinox EV
2024
2025
Silverado EV
2024
2025
BrightDrop 400
2025
2025
BrightDrop 600
2025
2025
2022
2025
2024
2025
Sierra EV
2024
2025
Involved Region or Country
Information
Engine:
—
to
—
All
All
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
This bulletin and criteria within are to determine the internal stability of the High Voltage
Battery and the 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 isolated vehicle storage guidance and repair instructions and
results MUST be documented in a TAC Case.
Perform the service instruction steps as indicated if any of the following DTCs listed are
set as CURRENT:
DTCs: P0AA6, U359E, P0AE3, P0C78, U1666, U1667, U2BFC, P1C34, OR P0AA7 set
by itself, OR if any of these DTCs are listed as HISTORY:
• P0AA6
• U359E
OR if directed here by a service procedure such as High Voltage System Inspection
(physical battery damage observed) or TAC.
Service Procedure
Warning: Never leave a vehicle or battery pack with an applicable DTC indoors overnight, plan all work to be
completed during normal business hours.
Copyright 2025 General Motors. All Rights Reserved.
Page 2
May, 2025
Bulletin No.: 23-NA-151
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 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.
1. Verify if DTCs U2BFC or P1C34 are set as current. If yes, immediately report results to TAC now as review will
be necessary to help determine stability.
2. Verify any of the following DTCs are set as CURRENT; P0AA6, P0AE3, P0C78, P1C34, U359E, U1666, U1667
or P0AA7 without other propulsion DTCs. Verify if the following DTCs are set as HISTORY: P0AA6 or U359E.
3. Obtain and document 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, did they hear a ‘pop’ or abnormal noise.
Danger: DO NOT add coolant without first confirming the Lithium-Ion Hybrid/EV Battery Pack internal
coolant passage can maintain proper vacuum and pressure. Adding coolant to the coolant system with an
internal lithium-ion Hybrid/EV Battery Pack coolant leak may result in Fire, which could result in vehicle or
component damage, and cause severe body injury or death.
4. Visually inspect the coolant level in the high-voltage battery surge tank (Fig 1 and 2) and document via photo.
Inform TAC if coolant has previously been added.
Note: This Data is found in K16 – Battery Energy Control Module -> Data Display -> Hybrid/Electric Vehicle Battery
Pack Thermal Stability Data.
6856200
5. Observe and record GDS2 data (Fig 3) :
• Most Recent Isolation Resistance - Pack and Pack 2 (as applicable). Greater than 6200K ohms is normal.
• Thermal Event Temperature Sensor. Near ambient and close to all other temperature sensors is normal.
Bulletin No.: 23-NA-151
May, 2025
Page 3
• Thermal Event Gas Sensor. 0 to 30,000 ppm and not rising is normal.
• Thermal Event Pressure Sensor. Near barometric pressure and not rising is normal.
• Interface Control Module Temperature (1 thru 24 as applicable). Near ambient and close to all other temperature sensors is normal.
6. If the vehicle is already on a hoist, you may perform the battery pack inspection steps that do not require battery
pack removal to perform.
7. Perform SPS2 Hybrid/EV Battery Data Retrieval, refer to 25-NA-044.
Danger: Damage to a Lithium-Ion hybrid/EV battery pack could result in fire, loss of electrical isolation or
exposure to high voltage. Until the high voltage system inspection has been completed, store the vehicle
with hybrid/EV battery pack installed outside in a secure area away from buildings and other vehicles and
protected from rain, snow, and other moisture.
8. Move the vehicle to a stable location outdoors: isolated and away from buildings, vehicles, and foot traffic while
waiting direction to diagnose/repair. Recommended distance is 50 feet (15M). Document isolated location via
photo (Fig 4 and 5). Refer to ‘Neutral Service Mode’ in electronic transmission range select service information if
required.
9. Start a TAC case and upload all photos and your GDS2 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.
Note: Perform the following steps at time of High Voltage Battery replacement. Depending upon the following results
you may be required to immediately move the High Voltage Battery outdoors after removal. Do NOT submit a core
pickup request unless given approval by TAC.
10. Following SI Procedure for high voltage battery removal, Hybrid/Electric Vehicle Battery Pack Removal, and
Installation:
10.1. Inspect the High Voltage Connectors at the High Voltage Battery for corrosion, moisture, and/or soot.
Take clear, close-up photos of the vehicle side HV connectors and High Voltage Battery connection
headers. Review Fig 8-10 for examples of light and heavy soot and the photo clarity required. Attach
photos to TAC Case.
Note: If soot, corrosion or moisture is observed, continue but contact TAC immediately upon completion.
10.2. Check 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 (Fig 6 and 7).
Note: If more than 3V is found, continue but contact TAC immediately upon completion.
10.3. Remove the High Voltage Battery Pressure Equalizer Vent and Battery Inspection plug (if equipped) (Fig
11 and 12). The equalizer vents have 4 fasteners and are located at the base of the battery. Wearing your
personal protection equipment use a cotton swab or paper towel to swab inside the enclosure for
moisture/coolant and/or soot. Take photos and attach to TAC case.
Note: Swabs are available in a pack of 20 as GM-47909-20.
Note: If fluid/soot is observed, continue but contact TAC immediately upon completion.
Danger: Do not insert anything other than a cotton swab or paper towel while performing the swab test.
10.4. Evacuate residual coolant from the High Voltage Battery coolant circuit. Refer to the SI Procedure for
Hybrid/Electric Vehicle Battery Pack Replacement and Shipping Preparation.
Note: If unable to remove coolant from the High Voltage Battery coolant circuit, continue but contact TAC immediately upon completion.
10.5. Vacuum test the High Voltage Battery coolant circuit for leaks. See Hybrid Battery Pack Coolant Passage
Leak Test (Fig 13 and 14). Attach photos to the TAC case.
Note: If the High Voltage Battery coolant circuit does not hold vacuum, continue but contact TAC immediately upon
completion.
10.6. Pressure test the High Voltage Battery coolant circuit for leaks (Only complete if passes vacuum test).
See Hybrid Battery Pack Coolant Passage Leak Test (Fig 15 and 16). Attach photos to the TAC case.
Note: If the High Voltage Battery coolant circuit does not hold pressure, continue but contact TAC immediately upon
completion.
Page 4
May, 2025
Bulletin No.: 23-NA-151
11. Place the High Voltage Battery in the provided DDR Crate & move outdoors: isolated and away from buildings,
vehicles, and foot traffic. Cover high voltage battery/DDR crate with a tarp to protect from the elements while
awaiting further direction (Fig 4). Take picture of location and upload into TAC Case. Report all results to TAC
for Engineering review.
23-NA-151 Hybrid/EV Stability Printable Checklist for VIN:_________________________________
Initial Vehicle Inspection
Steps
Results
Submission Check List
Inspect Coolant Level. Photograph result.
Danger: DO NOT add coolant without
first confirming the Lithium-Ion
Hybrid/EV Battery Pack internal coolant
passage can maintain proper vacuum
and pressure. Adding coolant to the
coolant system with an internal lithiumion Hybrid/EV Battery Pack coolant leak
may result in Fire, which could result in
vehicle or component damage, and
cause severe body injury or death.
Passed Example
Refer to Figure 1
Failed Example
Refer to Figure 2
Coolant Level Photo
__________
GDS2 Session Log. Battery Energy Control
Module>Data Display>Hybrid/Electric
Vehicle Battery Pack Thermal Stability Data
Refer to Figure 3
Pack Isolation
1___________ohms
2___________ohms
Thermal Sensor
__________C/F
Thermal Gas
__________PPM
Thermal Pressure
__________psi/kPa
Interface Temperature
(average)
___________C/F
GDS2 -Vehicle Battery Pack
Thermal Stability Data
Captured
__________
Move vehicle to stable location away from
buildings and other vehicles.
Recommended isolation distance is 50 feet
(15M) Photograph results.
Warning: Never leave a vehicle or battery pack with an applicable DTC indoors overnight, plan all work to be
completed during normal business hours.
Passed Example
Refer to Figure 4
Failed Example
Refer to Figure 5
Vehicle Isolated Outside and
Picture Captured/Submitted
__________
Start TAC Case (submit all the above).
Vehicle to stay isolated outdoors until Hybrid/
Electric Vehicle Battery Pack Removal and
Installation or under the direction of TAC during
any required diagnosis procedure.
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TSB/Document ID: 23-NA-151
Replacement Service Bulletin Number:
MFR Communication Date: 2025-05-16
MFR Internal Campaign ID/Software Version:
Communication Type: Service Bulletin/Repair Instructions
NHTSA Components: FUEL/PROPULSION SYSTEM
MFR Component System:
MFR Component Subsystem:
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