Service Bulletin

Bulletin No.:

18-NA-171

Date:

July, 2019

TECHNICAL
Subject:

Malfunction Indicator Lamp (MIL) Illuminated with DTC P0300
This Bulletin replaces PIP5490D. Please discard PIP5490D.

Brand:

Model:

Buick

Encore

Chevrolet

Cruze
Trax

Model Year:
from
2016

VIN:
to

from

to

2018

2018

Engine:

Transmission:

1.4L (LE2)

6T35 Automatic
(MNU) or
6 Speed
Manual (MF3)

Involved Region or Country

North America and N.A. Export Regions

Condition

Some customers may comment on a rough running engine with the Malfunction Indicator
Lamp (MIL) Illuminated.
Upon inspection, a technician may find DTC P0300 (Engine Misfire Detected) set in the
Engine Control Module (ECM) along with a misfire and low compression in one or more
cylinders.

Cause

This condition may be caused by a damaged piston requiring replacement.

Correction

Repair the engine mechanical concern based on the results of the Service Procedure
below.

Service Procedure
If you encounter a vehicle with the above concern,
perform an engine compression test. Refer to Engine
Compression Test in SI.
If low compression is found, perform a cylinder leakage
test. Refer to Cylinder Leakage Test in SI, and record
the test results to isolate the concern.
Note: To isolate the source of cylinder leakage to a
valve or cylinder sealing issue, it may be necessary to
remove the intake and exhaust manifolds.
If excessive leakage to the crankcase is isolated, check
all four cylinder walls for damage. If the cylinder wall
surfaces have not been damaged, replace all four
pistons and fill the crankcase with current specification
Dexos oil. Refer to Bulletin Number 16-NA-367.
An un-metered air leak in the induction system, or an
engine mechanical issue causing rough running, may
cause the ECM to learn an incorrect Throttle Body Idle
Airflow Compensation value over time. This incorrectly

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learned value may cause various symptoms to occur
such as MIL on with P1101 setting, rough or unstable
idle speeds and/or engine stall.
Once the mechanical repairs have been completed,
perform a throttle body inspection and cleaning. Refer
to Throttle Body Inspection and Cleaning in SI, followed
by Throttle Body Idle Air Flow Compensation Reset
function in GDS2.
Note: For the Cruze vehicles only – A calibration has
been released that will help to reduce the possibility of
a cracked piston. Update the engine control module to
the latest calibration available.

Parts Information
Note: The piston and rod assembly referenced in this
bulletin arrives with rod bolts that are allowed to be
removed and reused one time for final assembly to the
complete repair.

Page 2

July, 2019

Bulletin No.: 18-NA-171

Causal Part

Description

Part Number

Qty

X

Piston, Kit

12688861

4

Rod Asm-Conn

12688858

4

Retainer, Piston Pin

12639680

4

Bearing Kit, Con Rod

12674806

4

Gasket Kit, Cyl Head (inc bolts)

12687228

1

Filter, Oil

12674698

1

Seal, Cr/Shf Frt Oil

12661527

1

Seal Kit, F/Injrn Fuel Rl

12659782

1

GASKET, TMG CHAIN TENSR

12636523

1

Nut, Turbo

11102751

4

Gasket, Ctltc Conv

12641115

1

Shield, Turbo Ht

12673929

1

Pipe, Fuel Feed Inter

12684046

1

Gasket, Int Manif

12637018

1

Pan, Lwr Oil

12637773

1

Gasket, Cyl Head

12681524

1

Gasket, O/Pump

12644558

1

Gasket, O/Pump

12644557

1

Gasket, Int Manif

12637018

1

Gasket, Wat Otlt

12627061

1

Gasket, Cam Pos Sol

12636176

1

Bolt, Eng Mt

11610904

3

Bolt, Eng Mt

11547918

2

N/A

Bolt, Cr/Shf Balr

11611070

1

Seal, Turbo Cool Rtn Pipe

12662185

4

Washer, Turbo Oil Feed Pipe

12662184

2

Gasket, Turbo Oil Rtn Pipe

12640468

1

Warranty Information
For vehicles repaired under warranty, use the
appropriate labor operation associated with the repair
performed.

Version

4

Modified

Released May 22, 2018
August 06, 2018 – Added the Encore model and Parts Information section.
February 19, 2019 – Added a Note to the Parts Information section.
July 09, 2019 – Added the Trax model, Parts Information and Additional Keywords.

Additional Keywords: P0301, P0302, P0303, P0304

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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