Service Bulletin

Bulletin No.:

16-NA-405

Date:

May, 2020

TECHNICAL
Subject:

Poor Engine Performance in Extremely Cold Weather Conditions, PCV Bypass Hose
and Charge Air Cooler Icing for LUV Engines, Malfunction Indicator Lamp (MIL)
Illuminated - DTC P0299, P0236, P2227, P00C7 Set

Attention: For vehicles that are out of warranty and are identified on the Applicable Warranties
section in the GM Global Warranty Management system, refer to Special Coverage
#17157 or A192272980.
Brand:

Model:

Buick

Encore

Chevrolet

Trax

Model Year:

VIN:

from

to

2013

2020

from

to

Refer to Parts Information
section for breakpoints.

Engine:

Transmission:

Equipped with
1.4L
(RPO LUV)

Involved Region or Country

North America

Condition

Some customers may comment that when driving in extremely cold weather conditions
(-18°C or less / 0°F or less), their vehicle experiences one or several of the following
conditions:
• Loss of power.
• Smoke out the tail pipe.
• Hesitation on acceleration.
• Stalling condition.
• Burning oil odor possibly caused by oil leak.
• May also notice a Malfunction Indicator Lamp illuminated.
• After driving for a period of time, the driveability issues seem to diminish.
• Malfunction Indicator Lamp (MIL) Illuminated.
This condition may also cause an increase in crankcase pressure, creating oil leaks at
seals and gaskets.
The technician may find one or more of the following DTCs set:
• P0299
• P0236
• P2227
• P00C7

Cause

Correction

This condition may be caused by one or more of the following:
• Plugged crank case vent tube from ice forming in the tube during very cold weather
conditions.
• Ice accumulating in the intake manifold forming and blocking the PCV passage in the
cylinder head.
• Ice accumulation in the charge air cooler, restricting air flow to the throttle body.
Important: The PCV heater parts are only to be used in northern states or provinces
where temperatures are -18°C or less / 0°F or less and for critical customers only.
Note: U.S. vehicles are NOT built with the revised CAC or heated PCV bypass system.
To determine which CAC is installed in the vehicle, refer to Charge Air Cooler Outlet Air
Elbow Duct Replacement below.
If any of the following conditions are validated to be caused by freezing/icing, verification
of the following components is necessary on all U.S. and Canadian vehicles:
• Grille Winter Cover
• Heated PCV Bypass system

Copyright 2020 General Motors LLC. All Rights Reserved.

Page 2

May, 2020

Bulletin No.: 16-NA-405

• Modified Charge Air Cooler (CAC)
• Elbow Duct
If not previously performed, install either the grille cover, heated PCV bypass, CAC or
elbow duct.
If the vehicle came in for DTC P0299, but has all the components listed above installed,
perform the Intake Air Pressure and Temperature Sensor Inspection and Cleaning
procedure below.
If not previously performed, an oil change may be necessary to remove any moisture
from the engine. Prior to the oil change, run the engine at idle for an extended period of
time to melt any ice in the engine.

Important: Allow time for the vehicle to thaw in a warm
environment to avoid damaging or breaking parts that
may be required to be re-installed.

Grille Winter Cover Installation
Warning: Remove the grille cover when
temperatures are consistently above 32°F/ 0°C to
prevent engine and transmission overheating.
Remove the grille cover before towing a trailer of
any size. Failure to do so will decrease
transmission cooling efficiency and possibly cause
damage to the drivetrain.
Note: The cover may appear to be undersized. The
vinyl used may stretch during installation to ensure a
tight fit. It is highly recommended to warm the vinyl
cover so that it can be pliable enough to install onto the
front bumper fascia.

5193266

2. Attach the cover to the fascia by pushing the hooks
through the grille openings.
3. Validate that all the hooks are engaged and the
cover is a tight fit.

5197596

1. Using care, orientate the fascia winter cover to the
bumper fascia.

Bulletin No.: 16-NA-405

May, 2020

Page 3

Intake Manifold and Cylinder Head
Inspection
1. Remove the intake manifold. Refer to Intake
Manifold Replacement in SI.

5286434

2. Inspect the vacuum ports of the intake manifold for
ice accumulation.

5286457

3. Inspect the PCV intake runner for ice build-up
blocking the cylinder head as shown above.

5587832

Note: The charge air bypass regulator solenoid valve
can be affected if liquid has been found in the vacuum
tank. Draining of the fluid can be done through the
vacuum port (1).
5. Separate the charge air bypass regulator solenoid
valve vacuum line (2) from the intake manifold.

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May, 2020

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4. Clean any ice/sludge/water/carbon out of the PCV
pipes/hoses, the PCV nipple on the intake
manifold, the PCV intake runners and the orifice
between the #2 and #3 intake ports.

Bulletin No.: 16-NA-405

Bulletin No.: 16-NA-405

May, 2020

Page 5

5587732

6. Rotate the intake (1) to allow the fluid to bypass the
chamber internal to the manifold.
7. Tilt the intake (2) to allow the fluid to exit the intake
through the vacuum port.

5590616

5590615

8. Inspect the charge air bypass valve for oil leaking
from the vacuum side port.

• If oil is found leaking from the valve port,
disassemble and clean the components. Refer
to Charge Air Bypass Valve Replacement in SI.
• Only if necessary, replace the components.
9. Install the valve.
10. Install the intake manifold.

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May, 2020

Charge Air Cooler Outlet Air Elbow
Duct Replacement

Bulletin No.: 16-NA-405

Important: If this vehicle has the CAC outlet tube P/N
42698921 installed on the vehicle, replace the air duct
with the NEW kit part number 42751703.
Important: If the kit part number 42751703 is not
available, the dealer can order a new CAC outlet hose
part number 42731155.
1. Remove the charge air cooler outlet air hose. Refer
to Charge Air Cooler Outlet Air Hose Replacement
in SI.

5236304

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May, 2020

Page 7

5500499

2. Inspect the charge air cooler through the inlet to
determine if the vehicle has the new or old design.
• If the charge air cooler is the old design (shown
by X in the graphic), proceed to the Charge Air
Cooler Replacement section below.
• If the charge air cooler is the new design
(shown by the check mark in the graphic – note
the wider fin spacing and a division in the
middle of the charge air cooler), no charge air
cooler replacement is necessary.
3. Remove and clean the IAPT sensor.
4. Using care, remove the bands that secure the air
hoses to the elbow duct.

5410152

Note: The new elbow duct will have an estimated 45
degree mounting surface for the IAPT.
5. Install the new elbow duct onto the air hoses
aligning the duct to the marks.
6. Install the band clamps.
7. Install the IAPT sensor.
8. Install the charge air cooler outlet air hose.

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Bulletin No.: 16-NA-405

Intake Air Pressure and Temperature
Sensor Inspection and Cleaning

4910635

1. If necessary, remove the intake air pressure and
temperature (IAPT) sensor (2). Refer to Intake Air
Pressure and Temperature Sensor Replacement
in SI.

2. Inspect the IAPT sensor for any contaminates.

5020216

4910683

Important: Due to the sensitivity of the IAPT, Do Not
use any chemical cleaners including water and Do Not
use compressed air to remove contaminates.

3. Allow time for any ice build-up to melt by placing
the sensor port down.
4. Clean the sensor with a clean towel.
5. Inspect the IAPT sensor for any contaminates.
6. Install the sensor into the elbow duct.

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PCV Heater Installation
Notice: The PCV heater may have been installed
previously onto the vehicle. If the PCV heater has been
installed, proceed to step 35.
1. Operate the vehicle until it reaches operating
temperature.
2. Remove the battery. Refer to Battery Replacement
in SI.
3. Remove the engine cover.

2773935

4. Remove and discard the air cleaner outlet duct (2)
and resonator assembly.
Caution: DO NOT remove the vacuum hose from the
engine unless the vacuum hose shows apparent signs
of damage. Damage to the nipple on the intake
manifold may occur when attempting to disconnect the
vacuum hose.

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May, 2020

Bulletin No.: 16-NA-405

4855374

5. Using care, cut and remove the tape that secures
the vacuum line to the positive crankcase
ventilation (PCV) hose/pipe/tube.

2191937

Note: Original PCV pipe with vacuum line attached
removed from vehicle for illustrative purposes ONLY.

6. Remove and discard the PCV hose/pipe/tube (1)
leaving the vacuum line. Refer to Positive
Crankcase Ventilation Hose/Pipe/Tube
Replacement in SI.

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4910635

7. If necessary, remove the intake air pressure and
temperature (IAPT) sensor (2). Refer to Intake Air
Pressure and Temperature Sensor Replacement
in SI.

4855375

9. Using a tie strap, secure the vacuum line to the
engine wiring harness.
4377828

8. Install the block off plug (1) onto the turbocharger
PCV bypass port (2).

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4418077

10. Install the new air cleaner outlet duct (1) and air
resonator (3) assembly.
11. Using care, cut and remove the tape securing the
vacuum line to the NEW PCV pipe.
12. Remove the vacuum line from the PCV pipe
assembly.

Bulletin No.: 16-NA-405

4855376

13. Install the new PCV pipe assembly.
14. Install the PCV heater into air cleaner outlet duct.
15. Using Woven Polyester Electrical Tape (PET),
secure the vacuum line to the PCV pipe.

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2760835

16. Remove the fuse block cover (1).
17. Remove the nut (4) that secures the upper fuse
block to the body.
18. Loosen the three upper connector bolts (2).
19. Separate the upper (5) fuse block assembly from
the fuse block base (8) by releasing the snap
locks. Refer to Front Compartment Fuse Block
Replacement in SI.
20. Route the PCV wiring harness under the
battery tray.

4377876

21. For 2013-2016 model vehicles:
21.1. Remove UEX_X2 connector from the fuse
block base.
21.2. Remove connector cover.

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Bulletin No.: 16-NA-405

21.3. Install PCV heater wiring harness terminal
(1) into the J11 cavity (2).
⇒ Refer to X50A Fuse Block - Underhood X2 (Doc ID
4752878) in SI.
21.4. Route the wiring harness between the
battery and fuse block.

4379861

25. Position and snap the upper fuse block onto