19NA246

Bulletin No.:
Service Bulletin
Date:
19-NA-246
November, 2019
TECHNICAL
Subject:
Engine Runs Rough, Misfire, Malfunction Indicator Lamp (MIL) Illuminated DTC P0300 Set
This bulletin replaces PIP5661. Please discard PIP5661.
Brand:
Buick
Cadillac
Chevrolet
Model:
Model Year:
from
VIN:
to
from
to
Engine:
Transmission:
Envision
All
Regal
(AWD Only)
ATS
CTS
2019
2019
2.0 LTG
All
All
Camaro
All
Traverse
All
Involved Region or Country
United States, Canada, Mexico, Korea, Japan, Russia, Australia
Condition
Some customers may comment on one or more of the following conditions:
• Rough running engine
• Misfire
• MIL Illuminated
Some technicians may find DTC P0300 (Engine Misfire Detected) set in the Engine
Control Module (ECM).
Cause
Copyright 2019 General Motors LLC. All Rights Reserved.
This condition may be caused by the talc powder, inside the rubber boot of the coil,
having a lower dielectric strength compared to dielectric grease.
⇒ Talc was applied to prevent sticking of the rubber boot to the porcelain plug
for serviceability.
Page 2
November, 2019
Bulletin No.: 19-NA-246
Correction
5423956
1. Inspect all the spark plugs for signs of carbon tracking.
2. Perform a cylinder leak down test on the affected cylinder(s), making sure the
misfire is not caused by piston leakage and leakage into the crankcase. Refer to
Cylinder Leakage Test in SI.
• If there is no high cylinder leakage found, refer to the Spark Plug Inspection
Procedure section in this bulletin.
• If there is high cylinder leakage found, refer to the Piston and Engine Cylinder
Bore Inspection section in this bulletin.
Information
Spark Plug Inspection Procedure
This document assists the technician with
diagnosis and repair of a misfire for specific
scenarios as follows:
Scenario #1 - Misfire being caused by spark
plug carbon tracking.
Correction - Replace all four spark plugs, all four
ignition coils, apply dielectric grease to the spark plug
boots.
Scenario #2 - Misfire is being caused by a
damaged piston and the cylinder wall is
damaged.
Correction - Replace the engine assembly (engine
comes with spark plugs), all four ignition coils (apply
dielectric grease to the spark plug boots), the fuel
injector of the cylinder(s) that had damaged pistons and
other components necessary when an engine
assembly is installed.
Scenario #3 - Misfire being caused by a
damaged piston and the cylinder wall is not
damaged.
Correction - Replace all four spark plugs, all four
ignition coils (apply dielectric grease to the spark plug
boots), the fuel injector of the cylinder(s) that had
damaged pistons, all four piston kits, all ring sets for all
four pistons, all rod bearings, all four connecting rod
assemblies and other components necessary when
pistons are replaced.
5377263
If any carbon tracking is seen on any of the spark plugs,
replacement of all four spark plugs and all four coils is
required.
Important: All the boots will require grease. Refer to
the Dielectric Grease Application section below.
Bulletin No.: 19-NA-246
November, 2019
Page 3
Dielectric Grease Application
5423998
Use Molykote G-5008 Dielectric Grease.
5424004
5424001
1. Inspect all the ignition coils for grease or if
additional grease is required.
⇒ If additional grease is required, place a small
amount on a applicator stick or equivalent.
Note: Small amounts of grease “over spread” are
allowed on the spring.
2. Apply a thin coating in the rubber boot of the coil,
up to a depth of 15 mm.
Page 4
November, 2019
Bulletin No.: 19-NA-246
5424006
3. Remove any excess grease from around the end
of the boot and ensure there is not an excessive
amount within the boot.
5424009
The graphic above depicts grease applied evenly to the
inside of the boot, from the end of the terminal to the
end of the boot.
•
Piston and Engine Cylinder Bore
Inspection
Inspect the condition of all cylinder walls. Some light
vertical marks may be visible on the cylinder wall. In
these areas, check that the cross hatch marks are still
visible in this marked area. If they are, the cylinder
surface has not been compromised and the engine
block can be used. If you can catch your fingernail on
anything on the cylinder wall, the engine assembly
must be replaced.
•
If any of the cylinder walls are damaged, replace
the engine assembly (engine comes with spark
plugs), all four ignition coils (apply dielectric
grease to the spark plug boots. Refer to Dielectric
Grease Application section above), the fuel
injector of the cylinder(s) that had damaged
pistons and other components necessary when an
engine assembly is installed.
If the cylinder walls are not damaged, remove the
pistons and inspect for a fractured piston between
the top and second rings.
Bulletin No.: 19-NA-246
November, 2019
Page 5
The pictures below are some examples of what might
be found.
5375220
5375218
If the cylinder walls are not damaged and one or more
of the pistons are found fractured, replace all four spark
plugs, all four ignition coils (apply dielectric grease to
the spark plug boots. Refer to Dielectric Grease
Application section above), the fuel injector of the
cylinder(s) that had damaged pistons, all four piston
kits, all ring sets for all four pistons, all rod bearings, all
four connecting rod assemblies and other components
necessary when pistons are replaced.
Note: When installing pistons, make sure to use the
tapered ring compressor J-43953 special tool. Use care
when installing the piston assemblies into the cylinder
so the rings are not damaged.
Parts Information
Causal
Part
N/A
5375219
Description
Molykote G-5008
Dielectric Grease*
Part
Number
Material
Allowance
GM service
P/N
19260901
(Canadian
P/N
19260902)
$1.38 (U.S.)
$1.70
(Canada)
*There is enough material to do approximately 15 vehicles.
Store the remaining material for future use.
Page 6
November, 2019
Bulletin No.: 19-NA-246
Warranty Information
Note: Only use the appropriate labor operation for the
repair performed.
For vehicles repaired under warranty, use:
Labor
Operation
Description
Labor Time
4020061
Spark Plug Replacement Multiple
4066890
Piston, Connecting Rod, and
Bearing Replacement
4067490
Engine Replacement
Use
Published
Labor
Operation
Time
Version
1
Modified
Released October 30, 2019
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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