Subject: Hybrid/EV Battery, High Priority DTC’s , Potential Loss of Isolation,
Vehicle Handling and RESS Shipping Requirements

Brand:

Model
Year:

Model:

from

to

BrightDrop

Zevo 600

2023 2024

Cadillac

LYRIQ

2023 2024

VIN:

Engine:

Transmission:

All

All

from ot

Blazer EV
Chevrolet

2024 2024

-

-

Silverado EV

GMC

HUMMER EV

2022 2024

HUMMER EV
SUV

2024 2024

Involved Region or
Country

North America

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 replaced, perform the service instructions below 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
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.
1.

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, U2BFC or P1C34, U35B5 set as current or
history.
2. Visually inspect and document the coolant level in the high-voltage battery surge tank and document via photo.
3. 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).

4. Observe and record the Battery Energy Control Module parameter(s); K16 – Battery Energy 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).
5. 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).
Note: Record Top 3 Maximum Value or if all Similar provide average temperature.
6. 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.
7. Move Vehicle to stable location to store vehicle while waiting direction to repair. Document via photo and upload to
the TAC case.
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.
Note: Additional information or steps may be requested based on the information provided from steps 1-7 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.
8. Follow SI Procedure for RESS removal – Hybrid/Electric Vehicle Battery Pack Removal and Installation.
9. Inspect the High Voltage Connectors at the High Voltage Battery for Corrosion or Moisture. Take Photos of HV
Connectors and attach to TAC Case. Refer to the SI Procedure for High Voltage System Inspection.
Note: If corrosion or moisture is observed, stop all work and call TAC.
10. After RESS is removed from vehicle. Inspect High Voltage Battery Pressure Equalizer Vent Deflector or Battery
drain plug for any moisture or coolant. If no moisture or coolant present, complete swab test on the HV Battery
inspection port or drain plug depending on Make/Model and take photo(s) and attach to TAC Case. Refer to the SI
Procedure for High Voltage System Inspection.
Note: If fluid is observed, stop all work and call TAC.
11. Remove excessive coolant from the RESS pack. Refer to the SI Procedure for Hybrid/Electric Vehicle Battery Pack
Replacement and Shipping Preparation.
Note: If unable to remove coolant from the RESS pack, stop all work, and call TAC.
12. Vacuum test the High Voltage Battery coolant circuit. See Hybrid Battery Pack Coolant Passage Leak Test.
Note: If the High Voltage Battery coolant circuit does not hold vacuum, stop all work, and call TAC.
13. Pressure test the High Voltage Battery coolant circuit (Only complete if passes vacuum test). See Hybrid Battery
Pack Coolant Passage Leak Test .
Note: If the High Voltage Battery coolant circuit does not hold pressure, stop all work, and call TAC.
14. Report results to TAC and await further instruction.

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

2

Modified

Released September 05, 2023
Revised October 17, 2023 – Updated Model Years, Added Steps 8-12 and added Warranty Information.