23-NA-066

Service Bulletin
Bulletin No.:
23-NA-066
Date:
April, 2024
TECHNICAL
Subject:
Brand:
Malfunction Indicator Lamp (MIL) Illuminated - DTC P0402, P062D, P144E, P242B,
P2459, and/or P2635 Set
Model:
Chevrolet
Silverado 2500HD/
3500HD
GMC
Sierra 2500HD/
3500HD
Model Year:
Vehicle Build Date
Breakpoint:
from
to
from
to
2024
2024
SOP
July 1, 2023
Engine:
Transmission:
6.6L (L5P)
All
Involved Region or Country
North America, Israel, Palestine, Middle East
Condition
Some customers may comment on a MIL illuminated.
During diagnosis, a technician may find one or more of the following DTCs set in the
Engine Control Module (ECM):
P0402
P062D
P144E
P242B
P2459
P2635
Cause
This condition may be caused by a software anomaly.
Correction
Refer to N242438501.
– If N242438501 has been closed, refer to Service Information.
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 LLC. All Rights Reserved.
Parts Information
No parts are required for this repair.
Page 2
April, 2024
Bulletin No.: 23-NA-066
Version
5
Modified
Released March 11, 2023
Revised June 09, 2023 - Removed Software Anomaly information, Added Additional
DTCs to bulletin, Added New Service Procedure section and Added New Labor to
Warranty Information section.
Revised July 27, 2023 - Updated the third Dash Line under the Service Procedure to
Remove P2459.
Revised December 15, 2023 - Added SOP to July 1 to Vehicle Build Date Breakpoint.
Revised April 16, 2024 - Removed ECM Programing Information and added to Refer to
N242438501 in Correction 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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