Service Bulletin

Bulletin No.:

16-NA-380

Date:

June, 2020

INFORMATION
Subject:

Brand:

Diagnostic Tip for Malfunction Indicator Lamp (MIL) Illuminated, Excessive Smoke
from Tail Pipe - DTC P2002, P226D and/or P244A Set

Model:

Model Year:
from

to

VIN:
from

to

Chevrolet
GMC

Passenger Cars and
Trucks

2010

2020

Holden

Engine:

Transmission:

Any diesel
powered
vehicle with
a diesel
particulate
filter

Involved Region or Country

North America, Middle East, Israel, Korea, Argentina

Condition

Some customers may comment on the MIL illuminated and/or excessive smoke coming
from the tail pipe.
The technician may find one or more of the following DTCs set in the Engine Control
Module (ECM):
• P2002
• P226D
• P244A

Information

• P2002 code will set if the properly functioning system detects a cracked or broken
DPF. The exhaust particulate sensor is used to diagnose this failure. This code sets
when the ECM detects that the particulate filter has degraded beyond a calibrated
threshold.
• P226D code will set if the properly functioning system detects that the DPF is missing.
The exhaust pressure differential sensor is used to diagnose this failure. This code
sets when the ECM detects that the pressure difference over the DPF is less than a
set threshold.
• P244A code will set if the exhaust pressure differential sensor lines are disconnected
or blocked. The code sets when the ECM detects the diesel particulate filter exhaust
differential pressure sensor is lower than the minimum threshold.
A properly functioning diesel particulate filter should remove most if not all soot particles
from the exhaust stream. The following test should NOT be performed immediately after a
regeneration because of the reduced filtration efficiency of the DPF without any soot in it.
The purpose of this test is to aid in diagnosing a DPF that has failed internally.

Copyright 2020 General Motors LLC. All Rights Reserved.

Page 2

June, 2020

Service Procedure

Bulletin No.: 16-NA-380

Note: Assistance may be required to perform the
cheese cloth test.
Hold cheese cloth or equivalent across the opening of
the tail pipe. While doing this, have an assistant rev the
engine to the rev limiter and back to idle. Repeat this a
total of 8 times.
• A failed test will show excessive soot particulates
on the cheese cloth or equivalent (1, 2). Refer to
the graphic above. These soot particles indicate
that the exhaust particulate filter is no longer able
to capture all of the soot particles in the exhaust
stream and it needs to be replaced.
• A passing test will show no, or very minimal, signs
of soot particulates (3). These soot particulates
indicate that the exhaust particulate filter is able to
capture the soot particles in the exhaust stream
and it does not need to be replaced.
If the vehicle set P2002, P226D or P244A and SI
diagnostics leads to DPF replacement, use the cheese
cloth test to confirm if the DPF needs to be replaced.
5615225

Version

6

Modified

Revised August 31, 2017 – Updated the Model Years.
Revised July 23, 2018 – Added 2019 Model Year and additional vehicles.
Revised May 07, 2019 – Updated the Subject and Condition for SES Lamp Illuminated
and additional DTCs, added Engine RPOs, Information section, updated Exhaust Test
procedure and removed Warranty Information.
Revised August 26, 2019 – Eliminated Models and Engine RPO’s Designations, Added
2020 Model Year, Added Diesel Engine Statement
Revised June 08, 2020 - Update Service Procedure 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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