23-NA-038

Bulletin No.:
Service Bulletin
Date:
23-NA-038
March, 2023
TECHNICAL
Subject:
Harsh and/or Erratic Shifts After Over The Air (OTA) Update was Performed
Brand:
Model:
Cadillac
Chevrolet
Model Year:
from
Engine:
Transmission:
from
to
CT4
February 1
February 24
M5N
Silverado 1500
January 27
(Fort Wayne - Z)
January 27
(Oshawa - 1)
January 31
(Silao - G)
February 20
(Fort Wayne - Z)
February 20
(Oshawa - 1)
February 20
(Silao - G)
MQE
2023
GMC
Breakpoint:
to
2023
Sierra 1500
Involved Region or Country
North America, Europe, Uzbekistan, Middle East, Israel, Palestine, Brazil (Mercosur),
Bolivia (West), Chile (West), Colombia (West), Ecuador (West), Paraguay (West), Peru
(West), Uruguay (West), Japan, Cadillac Korea (South Korea)
Condition
Some customers may comment that after performing the OTA update, the transmission
shifts harsh and/or erratic.
Note: The harsh and/or erratic shifting should occur within 1-2 days after the OTA event.
Cause
This condition may be caused by the OTA update resetting the transmission shift adapts.
Correction
Perform the Transmission Service Fast Learn (SFL) following Techline Connect On
Screen Instructions to reset the transmission adapt values. After completing the SFL
procedure, the vehicle should be driven to evaluate shift quality.
– Use TSB 16-NA-019 as a guide to learn any shift that remains harsh or erratic after the
SFL to improve shift quality before returning the vehicle back to the customer.
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
Refer to Transmission Service Fast Learn Procedure in
the Service Manual.
Parts Information
No parts are required for this repair.
Copyright 2023 General Motors LLC. All Rights Reserved.
Page 2
March, 2023
Bulletin No.: 23-NA-038
Warranty Information
For vehicles repaired under the Powertrain coverage,
use the following labor operation. Reference the
Applicable Warranties section of Investigate Vehicle
History (IVH) for coverage information.
Labor Operation
Description
Labor Time
8486278*
Perform Transmission Service Fast Learn (SFL) After The
Over Air (OTA) Update
Use Actual Clock Time
*This is a unique Labor Operation for Bulletin use only.
Version
2
Modified
Released March 08, 2023
Revised March 21, 2023 - Update Information in the Correction section and Update the
Labor Time Information in the Warranty Information section.
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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