Bulletin No.:

Service Bulletin

Date:

23-NA-188
October, 2023

TECHNICAL
Subject:

Transmission Control Module Calibration Updates

Brand:

Model:

Chevrolet

Corvette

Model Year:

VIN:

from

to

from

to

2020

2024

—

—

Engine:

Transmission:

—

M1L, M1M

Involved Region or Country

North America, Europe, Middle East, Israel, Japan, Thailand, Australia/New Zealand

Condition

Some customers may comment on transmission related issues.
If a vehicle arrives for any transmission related concern, including all DTCs, the
technician should verify that the Transmission Control Module has the most current
calibration updates prior to any other repair.

Cause

The cause of the condition may be software anomalies. The new calibration update
addresses certain pressure DTCs.

Correction

The technician should document all DTCs in vehicle. Clear DTCs and record any DTCs
that reset. Perform Transmission Control Module calibration updates if available and
road-test the vehicle to verify DTCs do not return before releasing vehicle back to owner.
If no calibration updates available, the technician should follow diagnostic path of DTCs.

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.
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 12V jumper or booster pack disconnected
from the AC voltage supply. DO NOT connect a
battery charger.
Copyright 2023 General Motors LLC. All Rights Reserved.

•

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.
• 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

Page 2

October, 2023

Bulletin No.: 23-NA-188

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

Bulletin No.: 23-NA-188

October, 2023

Page 3

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

5877000

5644477

Important: Techline Connect screen 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. Record the WCC on the job card. No
further action is required. Refer to the Warranty
Information section of this bulletin.
1. Reprogram the Transmission Control Module.
Refer to Transmission Control Module
Programming and Setup in SI.

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October, 2023

Bulletin No.: 23-NA-188

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 the SPS Warranty Claim Code on the job
card for warranty transaction submission.

Bulletin No.: 23-NA-188

October, 2023

Page 5

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

Description

Labor Time

2810175*

Transmission Control Module Reprogramming with SPS

Use Published Labor
Operation Time

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

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.

Page 6

October, 2023

Bulletin No.: 23-NA-188

Warranty Claim Code Information Retrieval

6125774

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 October 25, 2023

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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