23-NA-066

Bulletin No.:
Service Bulletin
Date:
23-NA-066
December, 2023
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:
L5P
All
Involved Region or Country
North America, Israel, Palestine, Middle East
Additional Options (RPOs)
Equipped with 6.6L Engine (RPO L5P)
Condition
Some customers may comment on a malfunction indicator lamp 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
Correction
If you encounter a vehicle with the above concern, complete the following procedure
below.
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 2023 General Motors LLC. All Rights Reserved.
Service Procedure
Check for any ECM updates:
– If an update is available, refer to K20 Engine Control
Module: Programming and Setup in the Service
Manual.
– If an update is not available, refer to SI for the
code set.
– If an update is available, perform the Barometric
Pressure Sensor Reset found in the reset functions
of GDS2.
Page 2
December, 2023
Bulletin No.: 23-NA-066
Parts Information
No parts are required for this repair.
Warranty Information
For vehicles repaired under the Emission coverage,
use the following labor operation. Reference the
Applicable Warranties section of Investigate Vehicle
History (IVH) for coverage information.
Labor Operation
Description
Labor Time
2889648*
Engine Control Module Reprogramming with SPS for P0402,
P062D, P144E, P242B, P2459, and/or P2635
0.3 hr
Add
Barometric Pressure Sensor Reset
0.2 hr
*This is a unique Labor Operation for Bulletin use only.
Version
4
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.
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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