18NA361

Bulletin No.:
Service Bulletin
Date:
18-NA-361
October, 2020
TECHNICAL
Subject:
Brand:
Chevrolet
Diagnostic Tip for Diesel Fuel System Contamination, Malfunction Indicator Lamp (MIL)
Illuminated - DTC P026D, P2A00, P0171, P0172 and/or P0300 Set
Model:
Model Year:
VIN:
from
Engine:
from
to
Cruze
2014
2015
Cruze
2018
2019
Equinox
2018
2019
Silverado
2017
2018
6.6L Turbo
Diesel (L5P)
Silverado
1500
2020
2021
3.0L
Diesel (LM2)
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)
Sierra
2017
2018
6.6L V-8
Duramax Turbo
Diesel (L5P)
Sierra 1500
2020
2021
3.0L
Diesel (LM2)
Sierra
2500/3500
2019
2021
6.6L V-8
Duramax Turbo
Diesel (L5P)
Terrain
2018
2019
1.6L
Diesel (LH7)
1.6L
Diesel (LH7)
—
Involved Region or Country
North America, Israel
Condition
Some customers may comment that the MIL is illuminated.
Copyright 2020 General Motors LLC. All Rights Reserved.
Transmission:
2.0L
Diesel (LUZ)
—
GMC
to
—
Page 2
October, 2020
Bulletin No.: 18-NA-361
5168457
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
October, 2020
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
October, 2020
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
October, 2020
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.
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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
October, 2020
Bulletin No.: 18-NA-361
Version
7
Modified
Released December 10, 2018
June 24, 2019 – Added 2020 to Model Year.
August 14, 2019 – Added 2019 and 2020 Silverado HD Models.
October 03, 2019 – Added Information on Fuel/Water Filter Removal section.
October 14, 2019 – Removed LCF and added 2020 Silverado/Sierra 1500 with LM2.
September 09, 2020 – Added DTCs to the Subject, Condition and Information on Fuel/
Water Filter Removal sections.
October 20, 2020 – Added the 2021 Model Year to Silverado and Sierra Models and
additional engine descriptions.
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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