18NA361

Service Bulletin
Bulletin No.:
18-NA-361
Date:
May, 2021
TECHNICAL
Subject:
Diagnostic Tip for Diesel Fuel System Contamination, Malfunction Indicator Lamp (MIL)
Illuminated - DTC P026D, P2A00, P0171, P0172 and/or P0300 Set
Brand:
Model:
Cadillac
Model Year:
VIN:
from
to
Engine:
from
to
Esclade
2021
2021
3.0L Turbo
Diesel (LM2)
Cruze
2014
2015
2.0L
Diesel (LUZ)
Cruze
2018
2019
Equinox
2018
2019
Silverado
2017
2018
6.6L Turbo
Diesel (L5P)
Silverado 1500
2020
2021
3.0L Turbo
Diesel (LM2)
1.6L
Diesel (LH7)
Chevrolet
Silverado 2500/3500
2019
2021
6.6L V-8
Duramax
Turbo
Diesel (L5P)
Silverado 4500HD,
5500HD and 6500HD
2019
2021
6.6L V-8
Duramax
Turbo
Diesel (L5D)
Suburban
2021
2021
3.0L Turbo
Diesel (LM2)
Sierra
2017
2018
6.6L V-8
Duramax
Turbo
Diesel (L5P)
Sierra 1500
2020
2021
3.0L Turbo
Diesel (LM2)
—
—
Sierra 2500/3500
2019
2021
6.6L V-8
Duramax
Turbo
Diesel (L5P)
Terrain
2018
2019
1.6L
Diesel (LH7)
Yukon
2021
2021
3.0L Turbo
Diesel (LM2)
GMC
Copyright 2021 General Motors LLC. All Rights Reserved.
Transmission:
—
Page 2
Involved Region or Country
May, 2021
Bulletin No.: 18-NA-361
North America, Israel
Some customers may comment that the MIL is illuminated.
Condition
5168457
Note: If removing the fuel filter from the filter housing, clean the outside of the fuel filter
assembly prior to removing the fuel/water filter from the housing.
Some technicians may find metal particles in the fuel system during diagnostics.
Important: If the fuel/water filter has been removed for inspection, Do Not install the
filter back into the housing until the fuel/water separator reservoir has been cleaned.
Refer to the Information on Fuel/Water Filter Removal section below.
Some technicians may also find one or more of the following DTCs set in the Engine
Control Module (ECM):
• P0171: Fuel System Lean
• P0172: Fuel System Rich
• P026D: Injection Quantity Too High
• P0300: Engine Misfire Detected
• P2A00: HO2S Performance Sensor 1
Correction
If you encounter such a situation, DO NOT replace the fuel system as described in
Service Bulletin #16-NA-102.
Please perform the following fuel system flushing procedure prior to performing further
diagnostics.
Once the fuel system has been flushed, continue with diagnostics as described in SI.
Bulletin No.: 18-NA-361
May, 2021
Page 3
Information on Fuel/Water Filter
Removal
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5417311
Water or other like contaminates in the fuel will create
driveability concerns and loss of engine power. If water
and/or debris is present in the fuel system, the fuel
cannot cool and lubricate the components properly,
causing overheating, rust and corrosion. This can result
in component failure. Water and debris can enter the
fuel system in several ways, either through a
contaminated refueling source, plugged venting or
through long term condensation in the vehicle fuel
tanks.
1. Remove the fuel/water filter from the housing using
care not to separate the filter from the fuel/water
separator reservoir.
Page 4
May, 2021
5417298
2. Using care, separate the filter from the fuel/water
separator reservoir by placing the filter downwards
in a clean/dry drain pan.
Bulletin No.: 18-NA-361
5417283
– If the filter is facing upwards, debris left on the
sides of the filter may escape past the O-ring
seal during removal and settle in the fuel/water
separator reservoir.
– Water and/or debris left in the fuel/water
separator reservoir will flow past the filter, directly
into the fuel system when re-started.
– Debris that is allowed past the filter and into the
fuel system can cause fuel injection issues that
may set DTCs P2A00, P026D, P0300, P0172.
Replacement of fuel injectors without a complete
cleaning of the fuel system will only be a
temporary fix until the debris gets into the new
injectors.
3. Inspect the fuel/water separator reservoir and filter
for heavy debris.
• If heavy debris is found in the filter, clean the
fuel/water separator reservoir and continue to
the Fuel System Flushing Procedure below.
• If no signs of debris are found, clean the fuel/
water separator reservoir, install a new filter and
refer to SI for further diagnostics.
Bulletin No.: 18-NA-361
May, 2021
Fuel System Flushing Procedure
Note: Performing the test may aid in determining the
source and section of the fuel system causing the
contamination.
Page 5
7. Install a clear line between the fuel supply hose
and the fuel return hose.
8. Run the fuel pump until the fuel runs clear in
the line.
1. If removed, re-install the fuel filter.
5168447
5167517
2. Disconnect the chassis side fuel feed hose (3) from
the engine side fuel feed pipe (4).
3. Place the end of the chassis side fuel feed hose
into a clean container and run the fuel pump to
clean any debris left in the fuel lines, approximately
2-3 gallons (7.6-11.4L).
4. Clean the fuel/water separator reservoir.
5. Install a new fuel filter.
6. Disconnect the chassis side fuel return hose (2)
from the engine side return pipe (1).
Note: The white “Tubing” shown in the graphics below
depict the route of the clear line, not the length.
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9. Connect the fuel supply hose to the engine
supply pipe.
10. Install a clear line in series at the fuel return hose
to the engine return pipe.
11. Run the fuel pump until the fuel runs clear in
the line.
Reconnect all fuel lines and retest for any codes or
symptoms in the vehicle.
Parts Information
No parts are required for this repair.
Page 6
May, 2021
Bulletin No.: 18-NA-361
Version
8
Modified
Released December 10, 2018
Revised June 24, 2019 – Added 2020 to Model Year.
Revised August 14, 2019 – Added 2019 and 2020 Silverado HD Models.
Revised October 03, 2019 – Added Information on Fuel/Water Filter Removal section.
Revised October 14, 2019 – Removed LCF and added 2020 Silverado/Sierra 1500
with LM2.
Revised September 09, 2020 – Added DTCs to the Subject, Condition and Information on
Fuel/Water Filter Removal sections.
Revised October 20, 2020 – Added the 2021 Model Year to Silverado and Sierra Models
and additional engine descriptions.
Revised May 06, 2021 - Add Note to Condition section to clean the Filter Housing
Assembly.
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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