18-NA-035

Bulletin No.:
Service Bulletin
Date:
18-NA-035
February, 2023
INFORMATION
Subject:
Information on Transmission No Command Overdrive Ranges During Cold Ambient
Temperatures
Brand:
Model:
Buick
Cadillac
XT5
Model Year:
Holden
Transmission:
(Automatic)
2022
LE2, LUV
MNH
2023
LSY
2019
LE2
Encore
2018
XT4
2019
2020
Cruze
(Gen II - B)
GMC
Engine:
to
XT6
Chevrolet
VIN:
from
Equinox
2018
from
to
M3H
2023
—
—
2019
LFV
Trax
2022
LE2, LUV
2020
Terrain
Equinox
2018
Trax
2023
2020
MNU
LYX, LSD
Malibu
Acadia
M3G
MNH
LSY
M3G
LYX, LSD
M3U
1.5L
1.4L
6-Speed
Involved Region or Country
North America, Brazil, Colombia, Ecuador, Chile, Uruguay, Peru, Paraguay, Argentina,
Europe, Middle East, Israel, GM Korea Company, China, Australia/New Zealand, Egypt,
South Africa
Condition
Some customers may comment that the transmission will not shift into overdrive range
during cold ambient temperatures.
This condition may be caused by the engine control system detecting conditions that
indicate the freezing of moisture in the charge air cooler.
Note: Diagnostic aid overdrives ranges can only be commanded with GDS tool to
confirm correct transmission operation.
Information
When the control system detects the above conditions and the ambient temperature is
either below -10°C (14°F) or slightly above -10°C (14°F) with high moisture, but not
frozen, it takes the following actions:
• Requests a lower gear than normal (resulting in higher RPM).
• The system will enable the condition as needed to prevent freezing.
⇒ This strategy is to prevent a potential excessive air restriction due to an icing
condition, which would lead to a P0299 DTC and reduced engine
power mode.
Explain to the customer their vehicle is operating normally. Do not attempt to repair or
replace any parts to alter the original vehicle design intent. You may wish to give the
customer a copy of this bulletin.
Copyright 2023 General Motors LLC. All Rights Reserved.
Page 2
February, 2023
Bulletin No.: 18-NA-035
Version
6
Modified
Released February 2, 2018
Revised February 12, 2018 – Updated the temperature readings to 0°C (32°F) and
removed a transmission for the Terrain.
Revised February 21, 2019 – Removed M3U from Equinox, revised the Subject title,
added a Note and temperature slightly above 0°C (32°F) to the Information section.
Revised February 3, 2020 – Added the 2020 Model Year.
Revised February 09, 2021 – Added the Chevrolet and Holden Trax Model, Holden
Equinox, 2021 Model Year to applicable vehicles and updated the Involved Region or
Country section.
Revised February 01, 2023 – Removed Encore (VIN J), added Additional Models, added
2022 and 2023 Model Years to applicable vehicles, updated Involved Region or Country
section and replaced 0°C (32°F) with -10°C (14°F) in 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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