Bulletin No.: 24-NA-088

Service Bulletin

Date: May, 2024

INFORMATION
Subject:

Brand:

Diagnostic Tip for Malfunction Indicator Lamp (MIL) Illuminated,
Transmission Not Shifting/Default Mode - DTC P0747 Set

Model:

Model Year:
from

VIN:
to

from

Engine:
to

Transmission:

CT4
Cadillac

CT5

2023

Escalade
Models
Silverado
1500
Chevrolet

GMC

Silverado
2500HD/
3500HD

2023
2023

—

—

—

2024

Sierra 1500

2023

Sierra
2500HD/
3500HD

2024

MGM, MGU,
MHO, MHS,
MHT, MHU,
MHX, MQA,
MQB, MQC,
MQ2, MI2

Involved Region or Country

North America, Argentina, Brazil, Bolivia, Chile, Colombia, Ecuador, Paraguay, Peru, Uruguay, Europe, Kazakhstan, Uzbekistan, Middle East, Israel, Palestine, Japan, Cadillac
Korea (South Korea), Philippines, Australia/New Zealand, Other Africa

Condition

Some customers may comment that the MIL is illuminated, and the transmission has
defaulted and is not shifting.
Technicians may find during diagnosis that the TCM has set DTC P0747, and the transmission has defaulted to 5th gear.

Cause

This condition may be caused by the Transmission Control Valve Body that has most
likely failed causing the P0747 to set and the default condition.

Information

In most cases of DTC P0747, the control valve may only need replacement.
Refer to the Additional Information below for comparison.

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.

Copyright 2024 General Motors. All Rights Reserved.

Additional Information
Note: As the vehicle accumulates mileage, the transmission fluid will darken from thermal cycles and use.
The fluid should not have a burnt odor clutch debris in
the pan. Some accumulation of fine metallic debris
particles will accumulate on the magnets.
The following pictures were taken of transmissions
setting only DTC P0747:

Page 2

May, 2024

Bulletin No.: 24-NA-088

6639318

The fluid in the graphic above shows good color with no
evidence of clutch material. This unit should be
serviced with a valve body.

6639320

6639319

The fluid in the graphic above shows dark color with
minimal evidence of clutch material. This unit did not
exhibit a burnt odor. This unit should be serviced with a
valve body.

Version

1

Modified

Released May 16, 2024

The fluid in the graphic above shows extreme distress
and clutch material is starting to appear in the pan. This
unit should be removed from the vehicle and disassembled for inspection to determine what clutches have
been damaged. Any suspect clutch should be repaired
following published Service Information (SI), or the unit
replaced following Policy and Procedure Cost vs
Replace guidelines. The control valve body should be
replaced as well.

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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