Bulletin No.: 25-NA-121

Service Bulletin

Date: May, 2025

TECHNICAL
Subject:
Brand:

Chevrolet

GMC

Radio Software Version Y177– Multiple Updates for IOK
Model:

Model Year:
from

to

Silverado 1500

2025

2025

Silverado 2500 HD/
3500 HD

2025

2025

Sierra 1500

2025

2025

Sierra 2500 HD/ 3500
HD

2025

2025

VIN:
from

to

–

—

Engine:

Transmission:

All

All

Involved Region or Country

North America, Europe, Uzbekistan, Russia, Middle East, Bolivia (West), Chile (West),
Colombia (West), Ecuador (West), Peru (West), Japan, Cadillac Korea (South Korea),
Thailand (ASEAN), Other Africa, Argentina, Brazil, Paraguay, Uruguay

Additional Information (RPOs):

RADIO - INFOTAINMENT SYSTEM - 3.X MID/HIGH HMI, ENHANCED CONNECTIVITY
2.0, VOICE RECOGNITION (RPO IOK)

Condition

Some customers may comment on radio software related issues. Continuous
improvement software updates are being released with improvements made in several
areas.

Cause

The cause of the condition may be software anomalies.

Correction

A new radio software update, version Y177, was released to service for vehicles
equipped with Infotainment system RPO IOK. In addition to providing general robustness
and stability enhancements, this update includes all enhancements from previous
software version releases. Along with the vehicles mentioned above, vehicles in
unconnected markets may need the dealer to reprogram the radio with the new software
package.
Dealers are to update the radio and confirm the radio software update corrects the
customer’s concern. If the software update does not correct the customers concern,
please refer to SI diagnostics.
Note: To receive this software update, you DO NOT need to replace the module. This update can be performed via USB file transfer and programming through SPS 2.

Important: Improvements will vary by model, build configuration, system, and sales region. Not all vehicles have all
features.
Y177 Most Notable Improvements:
Audio:
• Additional improvements to prevent short cuts in audio especially at start up.
• Complete loss of audio improvements.
• When switching radio sources with the steering wheel switch, the display may be blank, but audio is still
present.
• The song skip button may be inoperable during a key cycle.
Apps:
• Unable to launch Spotify.

Copyright 2025 General Motors. All Rights Reserved.

Page 2

May, 2025

Bulletin No.: 25-NA-121

Display:
• The side card screen may show the maps loading, or if on the audio page it may be blank after switching to a
new user profile.
• Favorites bar may no longer be present.
• After a regular radio boot up, you may see loading audio on the screen and there will be no audio present.
OnStar:
• Device registration failing.
Trailering:
• General stability improvements in the trailing app.
Phone:
• Echo can be heard on the receiving side of a phone call.
• Bluetooth connection improvements.
• Bluetooth may disconnect and then reconnect when receiving a new message while creating a new profile.
Stability:
• Customer may see a return to dealer screen right at startup or after the splash screen animation.
• An over the air update may not process and may get stuck on the acknowledgement screen.
• Blank or blue screen may be present after a vehicle update has failed.
• After update is successful, there is no prompt after the radio restarts.
• Additional robustness to prevent black/blank screens.
• The settings app may crash when hitting back button in the Text-to-Speech output page.
SXM:
• When switching to SXM there will be no audio until you select another SXM station.
USB hubs:
• Center counsel USB hub may be inoperable.

Service Procedure
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.
Caution: Before downloading the update files, be sure the computer is connected to the internet through a network
cable (hardwired). DO NOT DOWNLOAD or install the files wirelessly. If there is an interruption during programming,
programming failure or control module damage may occur.
• Ensure the programming tool is equipped with the latest software and is securely connected to the data link
connector. If there is an interruption during programming, programming failure or control module damage may
occur.
• Stable battery voltage is critical during programming. Any fluctuation, spiking, over voltage or loss of voltage will
interrupt programming. Install a GM Authorized Programming Support Tool to maintain system voltage. Refer to
www.gmdesolutions.com for further information. If not available, connect a fully charged 12 V jumper or booster
pack disconnected from the AC voltage supply. DO NOT connect a battery charger.
• Follow the on-screen prompts regarding ignition power mode but ensure that anything that drains excessive
power (exterior lights, HVAC blower motor, etc.) is off.

Bulletin No.: 25-NA-121

May, 2025

Page 3

• Please verify that the radio time and date are set correctly before inserting USB drive into vehicle for
programming; otherwise, an error will result.
• Clear DTCs after programming is complete. Clearing powertrain DTCs will set the Inspection/Maintenance (I/M)
system status indicators to NO.
Important: The service technician always needs to verify that the VIN displayed in the TLC left side drop down
menu and the top center window match the VIN plate of the vehicle to be programmed prior to using Service
Programming System 2 (SPS2) for programming or reprogramming a module.
• For the TLC application, service technicians need to always ensure that the power mode (ignition) is “ON”
before reading the VIN from the vehicle’s VIN master module and that they do not select a VIN that is already in
the TLC application memory from a previous vehicle.
• If the VIN that shows up in the TLC top center window after correctly reading the VIN from the vehicle does not
match the VIN plate of the vehicle, manually type in the VIN characters from the vehicle VIN plate into the TLC
top center window and use these for programming or reprogramming the subject module with the correct vehicle
VIN and software and/or calibrations.
• The Engine Control Module (ECM) is the master module (for VIP vehicles) that TLC reads to determine the VIN
of the vehicle. If the VIN read from the vehicle by TLC does not match the VIN plate of the vehicle, the ECM
also needs to be reprogrammed with the correct VIN, software and calibrations that match the vehicle’s VIN
plate.
• The Body Control Module (BCM) is the master module (for GEM vehicles) that TLC reads to determine the VIN
of the vehicle. If the VIN read from the vehicle by TLC does not match the VIN plate of the vehicle, the BCM
also needs to be reprogrammed with the correct VIN, software and calibrations that match the vehicle’s VIN
plate.
Caution: Be sure the VIN selected in the drop-down menu (1) is the same as the vehicle connected (2) before
beginning programming.

5743643

Important: If the vehicle VIN DOES NOT match, the message below will be shown

Page 4

May, 2025

Bulletin No.: 25-NA-121

5877000

5644477

Important: Techline Connect screens shown above.
Important: If the same calibration/software warning is noted on the TLC Summary screen, select OK and follow
screen instructions. After a successful programming event, the WCC is located in the Service Programming System
dialogue box of the SPS Summary screen. No further action is required. Refer to the Warranty section of the bulletin.
1. Reprogram the Radio module. Refer to A11 Radio: Programming and Setup in SI.

Bulletin No.: 25-NA-121

May, 2025

Page 5

Dealers are to update the radio and confirm the radio software update corrects the customer’s concern. If the
software update does not correct the customers concern, please refer to SI diagnostics.

5644478

Note: The screenshot above is an example of module programming and may not be indicative of the specific module
that is being programmed. Module selection and VIN information have been blacked out.
Important: To avoid warranty transaction rejections, you MUST record the warranty claim code provided on the
Warranty Claim Code (WCC) screen shown above on the job card. Refer to callout 1 above for the location of the
WCC on the screen.
2. Record SPS Warranty Claim Code on job card for warranty transaction submission.

Parts Information
No parts are required for this repair.

Warranty Information
For vehicles repaired under warranty, use:
Labor Operation

Description

Labor Time

2810335

Radio Reprogramming with SPS

Use Published Labor
Operation Time

Important: **To avoid warranty transaction rejections, carefully read and follow the instructions below:

Page 6

May, 2025

Labor Operation

Bulletin No.: 25-NA-121
Description

Labor Time

6125814

• The Warranty Claim Code must be accurately entered in the “Warranty Claim Code” field of the transaction.
• When more than one Warranty Claim Code is generated for a programming event, it is required to document all Warranty
Claim Codes in the “Correction” field on the job card. Dealers must also enter one of the codes in the “Warranty Claim
Code” field of the transaction, otherwise the transaction will reject. It is best practice to enter the FINAL code provided by
SPS2.

Warranty Claim Code Information Retrieval

6125774

Bulletin No.: 25-NA-121

May, 2025

Page 7

If the Warranty Claim Code was not recorded on the Job Card, the code can be retrieved in the SPS2 system as
follows:
1. Open TLC on the computer used to program the vehicle.
2. Select and start SPS2.
3. Select Settings (1).
4. Select the Warranty Claim Code tab (2).
The VIN, Warranty Claim Code and Date/Time will be listed on a roster of recent programming events. If the code is
retrievable, dealers should resubmit the transaction making sure to include the code in the SPS Warranty Claim
Code field.
Version

1

Modified

Released May 13, 2025

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.

WE SUPPORT VOLUNTARY
TECHNICIAN
CERTIFICATION