Service Bulletin

Bulletin No.:

16-NA-405

Date:

May, 2023

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, P0234, 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:
from

to

2013

2021

VIN:
from

to

Refer to Parts
Information section for
breakpoints.

Engine:

Transmission:

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
• P0234
• P2227
• P00C7

Cause

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.

Copyright 2023 General Motors LLC. All Rights Reserved.

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Bulletin No.: 16-NA-405

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.
Important: The DTCs and symptoms above are not exclusively related to freezing/icing
conditions. Only follow this bulletin when the condition is directly correlated with extreme
cold of -18°C or less / 0°F or less. System leaks should always be ruled out first for
P0299. Signs of moisture will always be present in the CAC system and are not a reliable
indicator of freezing/icing.
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.

Correction

If any of the 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
• 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 has a verified icing condition associated with extreme cold, but has all the
components listed above installed, perform the Intake Air Pressure and Temperature
Sensor Inspection and Cleaning procedure and CAC drain procedure below.
If not previously performed, an oil change may be necessary to remove any moisture
from the engine. Prior to the oil change, warm the engine up completely to melt any ice in
the engine.
Note: It is not recommended to clean or flush the intake manifold or bypass solenoid.
If contamination (Ice/water/oil/sludge) at the charge air bypass valve is found, refer to
Service Bulletin # 22-NA-067 for intake replacement.

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.

5197596

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

Bulletin No.: 16-NA-405

May, 2023

Page 3

Charge Air Cooler Outlet Air Elbow
Duct Replacement

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.

Intake Manifold and Cylinder Head
Inspection
Refer to Service Bulletin # 22–NA–067.

5236304

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.

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May, 2023

Bulletin No.: 16-NA-405

6159510

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.

Bulletin No.: 16-NA-405

May, 2023

Page 5

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
Temperature Sensor Replacement in SI.

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.
2. Inspect the IAPT sensor for any 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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Bulletin No.: 16-NA-405

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.

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Page 7

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.

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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Bulletin No.: 16-NA-405

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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May, 2023

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.

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.

Page 9

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Bulletin No.: 16-NA-405

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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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
the base.

Tighten
4598974

22. For 2017-2020 model vehicles:
22.1. Remove the UEX_X3 connector from the
fuse block base.
22.2. Remove the connector cover.
22.3. Remove connector lock (1).
22.4. Install PCV heater wiring harness terminal
into the H6 cavity (2).
⇒ Refer to X50A Fuse Block - Underhood X3 (Doc ID
4752879) in SI.
23. Using tie straps, fasten the PCV wiring harness to
the connectors wiring harness at the white tape
indicators.
24. Install the connector back onto the fuse
block base.
Important: Only replace the fuse and install the labels
on vehicles that have a 5 amp fuse. Some vehicles
have the 10 amp fuse already installed and do not
require replacement or the label.

Tighten the bolts (1) to specifications. Refer to
Fastener Specifications in SI.
26. If necessary, replace the 5 amp fuse with a 10 amp
fuse into cavity F17 (2).
27. Install the front compartment fuse block cover.

4605957

28. Install the PCV heater wiring harness ground wire
(2) to ground G103 (1).

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Bulletin No.: 16-NA-405

4379843

29. If necessary, install the UEC sticker onto the