23-NA-027

Service Bulletin
Bulletin No.:
23-NA-027
Date:
April, 2023
TECHNICAL
Subject:
Brand:
Chevrolet
GMC
Poor Engine Performance, Engine Misfires, Malfunction Indicator Lamp (MIL)
Illuminated - DTC P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0300,
P0301. P0302, P0303, P0304, P0305, P0306, P0307, P0308 Set
Model:
Model Year:
from
Silverado
2500HD/3500HD
2017
Silverado
4500HD, 5500HD
and 6500HD
2019
Sierra 2500HD/
3500HD
2017
to
VIN:
from
to
Engine:
Transmission:
L5P
2023
-
-
L5D
-
L5P
Involved Region or Country
North America, Middle East, Iraq, Israel, Palestine, Australia/New Zealand
Condition
Some customers may comment on one or more of the following:
• Poor engine performance
• Engine misfires
Some technicians may find one or more of the following codes set in the Engine Control
Nodule (ECM):
• P0201
• P0202
• P0203
• P0204
• P0205
• P0206
• P0207
• P0208
• P0300
• P0301
• P0302
• P0303
• P0304
• P0305
• P0306
• P0307
• P0308
Cause
This condition may be caused by the engine vibration creating wear between the injector
connector terminal and the high pressure diesel fuel injector.
Correction
Whenever a high pressure diesel fuel injector is diagnosed as needing to be replaced,
follow the Service Procedure below to verify if the electrical connector is the cause.
Copyright 2023 General Motors LLC. All Rights Reserved.
Page 2
April, 2023
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
6279590
1. Using Diagnostic Test Probe J-35616-35 (VT), test
all the electrical connectors. Refer to Probing
Electrical Connectors in SI.
⇒ While testing these connectors, examine the
connector for indications of fretting or black
powder on the connector or connector seal as
shown in the graphic above.
2. If any connectors fail the probe test or the visual
inspection, replace that connector. Refer to Wire to
Wire Repair in SI.
Bulletin No.: 23-NA-027
Bulletin No.: 23-NA-027
April, 2023
Page 3
6279591
3. When replacing the connector:
• Odd Bank (1)
• Even Bank (2)
⇒ Verify that the wires will be able to be routed as
shown in the graphic above.
⇒ Verify that the wires are not being stressed
where the connection is made.
4. Prior to installing the electrical connectors to the
injectors, apply di-electric grease to each
connector.
Parts Information
The Dupont MOLYKOTE 4 Electrial Insulating
Compound listed below can be sourced locally from the
Dow Chemicals/Dupont distributor in your area.
Causal
Part
Description
Part
Number
Qty
X
CONNECTOR
KIT, ENG
WRG HARN
19368140
As Required
N/A
ACDelco
Dielectric
Lubricant*
12345579
(U.S.)
1
N/A
Dupont
MOLYKOTE 4
Electrial Insulating
Compound* (Or
Equivalent)
In Canada
— Obtain
Locally
1
*There is enough material to do additional vehicles. Store
the remaining material for future use.
4599048
Note: Examine the underside of the deadener (1) for
evidence of wire contact.
5. Prior to installing the deadener, verify that the wire
routing doesn't come into contact with said
deadener.
Page 4
April, 2023
Bulletin No.: 23-NA-027
Warranty Information
Important: Only use the Labor Operation number that
coincides with the repair performed.
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.
Note: Emission Warranty Coverage Code E applies to
Labor Operation 4088918.
Labor Operation
Description
Labor Time
4088918*
Diagnosis and Testing for Fuel Injector Electrical Connectors
0.5 hr
Add
L5P Injector Electrical Connector Repair (#3) Right Side
2.6 hr**
Add
L5P Injector Electrical Connector Repair (#1, 5, 7) Right Side
1.7 hr**
Add
L5P Injector Electrical Connector Repair Left Side
1.7 hr**
Add
L5P Each Electrical Connector Replacement
0.4 hr
Add
L5D Injector Electrical Connector Repair Bank 1
2.0 hr**
Add
L5D Injector Electrical Connector Repair Bank 2
1.7 hr**
Add
L5D Each Electrical Connector Replacement
0.4 hr
*This is a unique Labor Operation for Bulletin use only.
** For add times, refer to appropriate injector replacement time.
Version
2
Modified
Released March 16, 2023
Revised March 31, 2023 - Changed Emissions Coverage to Powertrain Coverage under
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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