Model Year:
from

VIN:
to

from

Engine:

Transmission:

to

Chevrolet

Silverado
3500HD

2024 - 2026

All

All

All

All

Chevrolet

Silverado EV
WT

2024 - 2026

All

All

All

All

Chevrolet

Silverado EV
RST

2024 - 2026

All

All

All

All

Chevrolet

Suburban

2021 - 2026

All

All

All

All

Chevrolet

Tahoe

2021 - 2026

All

All

All

All

Chevrolet

Traverse (all
new)

2024 - 2026

All

All

All

All

GMC

Acadia

2024 - 2026

All

All

All

All

GMC

Canyon

2023 - 2026

All

All

All

All

GMC

HUMMER EV 2022 - 2026

All

All

All

All

GMC

HUMMER EV 2024 - 2026
SUV

All

All

All

All

GMC

Sierra 1500
2022
New (RPO
J22, VIN Digit
12 = A or D)

All

All

All

All

GMC

Sierra 1500

2023 - 2026

All

All

All

All

GMC

Sierra
2500HD

2024 - 2026

All

All

All

All

GMC

Sierra
3500HD

2024 - 2026

All

All

All

All

GMC

Sierra Denali
EV

2024 - 2026

All

All

All

All

GMC

Terrain

2025-2026

All

All

All

All

GMC

Yukon

2021 - 2026

All

All

All

All

GMC

Yukon XL

2021 - 2026

All

All

All

All

Involved Region or Country

North America

Condition

Some technicians may experience one or more of the following concerns:
1. No Start
2. Vehicle will not crank
3. Vehicle will not enter into Key On, Engine Off mode (Service Mode)
4. Vehicle's Instrument Panel Cluster will not Illuminate
5. Vehicle will not shut Off.
In addition to the above concerns, when using GDS2 to connect to the vehicle, the pop
up message seen below will be displayed, prompting to turn the ignition on, but the
ignition can not be turned on. In some cases, after several ignition button presses, the
ignition may turn on. Then, the customer or dealer technician may notice that blower
motor turns on at a higher speed and then the ignition will not be able to be turn Off.

Cause

This may be caused by either an issue with Can Bus 2, the vehicle received an "Over
The Air" (OTA) update that has failed/ or the vehicle's electrical system was damaged by
a voltage spike such as a lightning strike or an incorrect jump start procedure.

Correction
The following are some diagnostic tips to help isolate the concern:

Bulletin No.: PIT5985K

January, 2026

Page 3

1) Dealership technicians will notice that they are unable to access GDS data to review DTC's or check the network
communication status. They may experience the following pop up box, shown below, and will be unable to get past
this screen. You will need to keep hitting the continue button 5-6 times and then it will allow you to get past this
screen and then it will be possible to go into vehicle diagnostics to check DTC's and CAN bus status

6278612

2) Next, use GDS2 Network Communication Status and check each CAN bus (1-9) to determine which modules are
communicating and which modules are not communicating. This is similar to the Detected State feature of the Data
Bus Diagnostic Tool (DBDT), but the DBDT will not work on these models. The GDS2 Network Communication
Status can be found by following this GDS2 path: Vehicle Diagnosis/Vehicle Communication Diagnostics/Network
Communication Status.
Go through each CAN bus tab (CAN bus 1-9) and note/document the communication status of each module. When
switching from tab to tab you may want to wait 25-30 seconds to see if modules show up. The picture below shows
an example of CAN bus 2 status.
Diagnosis and repair any modules that are not communicating. If a module fails to communicate due to a failed OTA,
first try to recover the module by reprogramming the module using SPS. Then clear all DTC's and recheck for
concern.

Page 4

January, 2026

Bulletin No.: PIT5985K

6278615

3) If after all modules are communicating and you continue to have issues or current DTC: U1962, then perform a
Serial Data Authentication Configuration (SDAC), which is located on the SPS controller screen in the SPS, shown
below. This will have to be completed so each module recognizes each other on their respective data buses.

6278616

4) If the SDAC fails, it will attempt to run a total of 3 times. If it fails after the third attempt, an additional screen will
pop up, identifying which module is causing the SDAC to fail. Be patient, as this pop-up screen may take up to
25-30 seconds to appear. Take a picture of the pop-up screen and reference the latest version of 25-NA-192
5) If the SDAC passes and a labor code is generated, make sure to clear all the U codes that are current or the
vehicle still may not start.

Bulletin No.: PIT5985K

January, 2026

Page 5

6278613

Version

11

Modified

02/28/2023 - Created on.
03/06/2023- Updated to add Brightdrop Model EV600.
08/30/2023- Update to add 2024 model's years and add Blazer EV and 2024 Silverado
and Sierra HD models.
11/17/2023- Updated to add model years and new models that have added VIP.
06/26/2024- Update models and model years.
08/27/2024- Update correction field and model years.
10/28/2024- Update models to 2025 Model years.
12/13/2024- Update to add new models and model years.
01/10/2025- Update to add new models and model year.
01/24/2025- Update to add new models and model year.
01/26/2026- Update models to 2026

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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