Bulletin No.: 24-NA-146

Service Bulletin

Date: August, 2024

TECHNICAL
Subject:

Brand:

Cadillac

Improved NVH and Knock Detection Diagnostics Available through ECM
Software Download

Model:

CT5

Model Year:

VIN:

from

to

from

to

2022

2024

-

-

Engine:

Transmission:

6.2L (RPO LT4)

All

Involved Region or Country

United States, Canada, Middle East, Israel, Palestine, Japan, Cadillac Korea (South
Korea)

Additional Options (RPOs)

Equipped with 6.2L Engine (RPO LT4)

Condition

General Motors has identified a calibration improvement for the 2022-2024 Cadillac CT5
6.2L engine RPO LT4.
This improvement helps isolated areas of the knock system to improve attenuation,
reducing noise and vibration. Some customers may also notice a lack of power or noise
under heavy loads especially while using a lower octane fuel.

Correction

As part of continuous improvement, engineering has released an updated calibration for
knock system response.
To take advantage of these improvements, an updated ECM calibration is available.
Please reprogram the ECM using the following 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.

Service Procedure
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

Copyright 2024 General Motors. All Rights Reserved.

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 12V 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.
• 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.

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August, 2024

• 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

Bulletin No.: 24-NA-146

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.

Bulletin No.: 24-NA-146

August, 2024

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5877000

5644477

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August, 2024

Bulletin No.: 24-NA-146

5431207

Important: Techline Connect and TIS2WEB screens
shown above.
Important: If the same calibration/software warning is
noted on the TLC or SPS 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. Record the WCC on the job card. No
further action is required. Refer to the Warranty Information section of this bulletin.
1. Reprogram the Engine Control Module or (ECM).
Refer to K20 Engine Control Module: Programming
and Setup in SI.

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5644478

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August, 2024

Bulletin No.: 24-NA-146

5431209

Note: The screenshots above are 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 SPS Warranty Claim Code (WCC) screen shown
above on the job card. Refer to callout 1 above for the
location of the WCC on the SPS screen.
2. Record the SPS Warranty Claim Code on the job
card for warranty transaction submission.

Bulletin No.: 24-NA-146

August, 2024

Page 7

Parts Information
No parts are required for this repair.

Warranty Claim Code Information Retrieval

Warranty Information

If the SPS Warranty Claim Code was not recorded on
the Job Card, the code can be retrieved in the SPS
system as follows:

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

4088478*

Engine Control Module
Reprogramming for Knock
System and NVH Improvements

0.3 hr

1. Open TLC/TIS on the computer used to program
the vehicle.
2. Select and start SPS/SPS2.
3. Select Settings.
4. Select the Warranty Claim Code tab.

*This is a unique Labor Operation for bulletin use only.
Important: To avoid warranty transaction rejections, carefully read and follow the instructions below:
• The Warranty Claim Code must be accurately entered in the “SPS 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 “SPS Warranty Claim Code” field of
the transaction, otherwise the transaction will reject. It
is best practice to enter the FINAL code provided by
SPS/SPS2.

Version

1

Modified

Released August 01, 2024

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.

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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