Bulletin No.: PIC6602U

Service Bulletin

Date: April, 2026

PRELIMINARY INFORMATION
Subject:
Brand:

IOK Radio Issues
Model:

Model Year:
from

VIN:
to

from

Engine:

Transmission:

to

Zevo 600

2023

All

All

All

All

Chevrolet

Corvette

2024-2025

All

All

All

All

Chevrolet

Silverado
1500

2022-2026

All

Chevrolet

Silverado
2500

2024-2026

All

Chevrolet

Silverado
3500

2024-2026

All

Chevrolet

Suburban

2022-2024

All

Chevrolet

Tahoe

2022-2024

GMC

Sierra 1500

2022-2026

GMC

Sierra 2500

GMC

T

BrightDrop

All

All

All

All

All

All

All

All

All

All

All

All

All

All

All

All

All

All

All

2024-2026

All

All

All

All

Sierra 3500

2024-2026

All

All

All

All

GMC

Yukon

2022-2024

All

All

All

All

GMC

Yukon XL

2022-2024

All

All

All

All

GMC

Hummer EV

2022-2023

All

All

All

All

GMC

Hummer EV
Pickup

2024-2025

All

All

All

All

GMC

Hummer EV
SUV

2024-2025

All

All

All

All

R

AF

All

United States

Additional Options (RPO)

IOK

Condition

Customers may comment of:
- No audio concerns.
- Blank, Black, Freezing/Frozen, or Glitching Display screen.
- "Return to Dealer" or "Demo Mode" message on the display.
- Phone connectivity concerns

Cause

Concerns may be software, connection, or hardware.

D

Involved Region or Country

Correction

Note: If the VIN you need a radio for is part of N252504460- Customer Satisfaction Program - Radio Replacement
and Reprogramming this PI is not applicable, please call/order as per step 1.8 below and state that the part is
required for a VIN applicable to N252504460- Customer Satisfaction Program - Radio Replacement and Reprogramming
1. For a blank or black radio display concern refer to PIC6629

Copyright 2026 General Motors. All Rights Reserved.

Page 2

April, 2026

Bulletin No.: PIC6602U

Note: This step does not apply to screens that go blank and recover, if the vehicle comes in with this concern
proceed to step 1.2 and update the vehicle to the latest software
1.1 For a return to dealer or Demo Mode message displayed on the radio screen see PIT6209, if the display shows
Device is Starting and is stuck on that screen, please refer to PIC6630.
1.2 Check current software and verify the radio software is up to date per:
• 25-NA-318 for 2022-2026 LD Trucks, 2024-2026 HD trucks and 2022-2024 SUVs
• 24-NA-168 for Hummer 2022-2024
• 25-NA-098 for Corvette and MY2025 Hummer
If the radio is not at latest software level update the radio, clear all codes and recheck for concern.
1.3 If the customer came in with a phone connectivity concern, please make sure that the customers phone is
updated to the latest iOS or Android software before proceeding further.

T

1.4. For audio concerns including intermittent 1-2 second loss of audio or loss of audio for an entire ignition cycle
see PIT6406
1.5. If concerns continue perform a radio data wipe by going to SPS, select A11 radio, then select *ONLY USE if
following PIC6630 instructions*- Radio data reset and follow the on screen instructions.
Note: For the purposes of this PI ignore*ONLY USE if following PIC6630 instructions* and perform the data reset

AF

Note: Once this operation is performed, the customer will need to log back into their google account, and repair any
mobile devices that were saved on the radio
1.6 Perform a wiggle test where the wire meets the connector body of the LVDS cable at the radio and display. If
display recovers, replace the LVDS cable
Note: For ease of access please check the LVDS connection at the radio first if display has not been undone from
the vehicle.
1.7 If concerns continue disconnect, inspect, and reconnect all related connections, clear any codes and recheck for
concern.
1.8 After the Date wipe has been performed, if concerns are still present for the symptoms below DO NOT
REPLACE THE RADIO:
• A complete loss of audio over an Ignition cycle or short cuts in audio mentioned in PIT6406.

R

• Phone connectivity issues.

DO NOT REPLACE THE RADIO for these issues as it will not correct the customer's concern. Engineering is aware
of the issue and investigating the root cause we ask to please be patient until a resolution is published.

D

1.9 If concern is still present and is not a software anomaly mentioned in step 1.7, these radios are currently
restricted through the Electronic Service Center (ESC). Please contact your preferred ESC to order the new radio.
The ESC will require a response to the attestation question before authorization will be provided. Attestation
question: Have you followed, reset the module, installed the latest software, disconnect and reconnect, and that the
radio still requires a replacement?

Bulletin No.: PIC6602U

April, 2026

Page 3

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.
Description

Labor Time

2810335

Update radio to latest
software

Use
Published
Labor Time

*3480578

Disconnect and reconnect
Radio module

1.0 Hrs.

Radio Replacement per
TAC Instructions

MY22-25
Hummer SUV
and Pickup
1.1 Hrs.
MY22.5-25
Silverado and
Sierra 1500
1.2 Hrs.
MY24-25
2500/3500HD
1 Hr.
MY24-25
Corvette 1.3
Hrs.
MY22-24
Tahoe/
Suburban/
Yukon/Yukon
XL 1.1 Hrs.

AF

3480688

T

Labor
Operation

*This is a unique Labor Operation for Bulletin use only.

Version

20

04/30/2025 Created on.
05/01/2025 - Updated Correction.
05/13/2025 - Updated Correction.
05/29/2025 - Updated Models.
06/19/2025 - Update to the Correction.
06/30/2025 - Update to correction
07/23/2025 - Updated correction to ESC restriction
07/30/2025 - Update to correction
08/14/2025 - Updated to correction to ESC restriction
10/03/2025 - Updated to change labor operation for programming per BQM request
10/08/2025 - Updated to add note to not replace radio for audio issues
10/17/2025 - Updated to add 25-NA-318 for 2022-2023 LD Trucks and 2024 HD trucks
10/23/2025 - Updated to add 25-NA-318 for 24 LD Trucks and 2024 SUVs
11/11/2025 - Update to the correction
11/18/2025 - Update to the correction
12/02/2025 - Update to the correction
02/06/2026 - Update to the correction section removed 25-NA-121 and add all vehicles to
25-NA-318
02/26/2026 - Update to correction to add 2022 SUV's to 25-NA-318
03/06/2026 - Updated to change step 1.5 in correction from PIC6209 to PIC6630
04/23/2026 - Updated to add LVDS cable wiggle test to correction section

D

R

Modified

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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