PIT6406B Service Bulletin/Repair Instructions

Bulletin No.: PIT6406B
Service Bulletin
Date: October, 2025
PRELIMINARY INFORMATION

Subject:

Brand:
Complete Audio Loss Through a Drive Cycle or Short Cuts in Audio

Model:
Model Year:

from
VIN:

to
from
Engine:
Transmission:
to
Chevrolet
Silverado

1500
2022-2026
All
All
All
All
Chevrolet
Silverado

2500
2024-2026
All
All
All
All
Chevrolet
Silverado

3500
2024-2026
All
All
All
All
Chevrolet
Suburban
2022-2024
All
All
All
All
Chevrolet
Tahoe
2022-2024
All
All
All
All
GMC
Sierra 1500
2022-2026
All
All
All
All
GMC
Sierra 2500
2024-2026
All
All
All
All
GMC
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
Involved Region or Country
GME, GMIO, GMNA, GMSA and Holden
Additional Options (RPO)
Equipped with RPO UQA, UQF, UQS, or NKD
Condition
Some customers may comment that they intermittently have no audio and no turn signal

click clack through a drive cycle, or short cuts in audio
Cause
The cause of the condition may be hardware and software anomalies.
Correction

Service procedure:

1. Verify radio is at the latest software.

2. Once vehicle is at latest software refer to concern 1 or 2 based off customer complaint.

Concern 1- Complete loss of audio throughout drive cycle (RPO: UQA ,UQS, and UQF with NKD only)

1. For model year 23 and 24 UQA and UQS vehicles ONLY, verify the part number of the amplifier below via GDS 2.

For model year 22 and 25 vehicles with UQA, UQS, or UQF with NKD, proceed to step 2.

a. UQA: 85661488, 85661516, 86587284, 86587287

b. UQS: 85661494, 85661517, 86587285, 86587288

1.1 If PN matches above replace the amplifier and retest for concern.

If the concern of Loss of Audio Throughout Drive Cycle remains.
Copyright 2025 General Motors. All Rights Reserved.
Page 2
October, 2025
Bulletin No.: PIT6406B
2. Verify No audio for the duration of the ignition cycle, but may return on the next key cycle and No turn signal “click

clack”

3. If the customer experiences this concern, please perform a global reset to the vehicle and audio should recover. If

audio recovers, this is due to a software anomaly. Do not replace the radio or the amplifier.

4. If audio does not recover, please refer to SI diagnostics.

Concern 2: Short cuts in audio throughout the key cycle

1. If the customer concern is Short Cuts in Audio throughout the key cycle. This is due to a software anomaly. Do not

replace the radio or amplifier.

Engineering is aware of the issues and investigating.
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
2810335
Reprogram Radio with

SPS
Use

Published

labor time

guide
*3481258
Verify amp part number

through GDS 2 MY23 and

24 vehicles only
0.3 Hr.
3421200
Amplifier replacement
Use

published

labor time

guide
*3481268
Verify Various audio

concerns in radio
0.2 Hr.
3481248
Perform Global Reset for

Loss of Audio and Audio

Returns
0.4 Hr.
*This is a unique Labor Operation for Bulletin use only.
Version
3
Modified
Created on 06/30/2025 replacing PIT6101 and PIT6367.

07/07/2025 – Updated to change correction.

10/06/2025 – Updated to add 2026 Model Year
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

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