Bulletin No.:

Service Bulletin

Date:

23-NA-058
August, 2023

TECHNICAL
Subject:

Cold Start Rattle Noise from the Engine Compartment, Malfunction Indicator Lamp
(MIL) Illuminated - DTC P0299 Set
This bulletin replaces PIP5829A. Please discard PIP5829A

Model Year:

Brand:

Model:

Buick

Encore GX

2020

Chevrolet

Trailblazer

2021

from

to

VIN:
from

Engine:

Transmission:

to

2023

1.2L (LIH)

Involved Region or Country

North America

Condition

Some customers may comment on one or more of the following conditions:
• MIL illuminated
• Cold Start Rattle Noise from the Engine Compartment
Some technicians may find DTC P0299 (Engine Underboost) Current or in history of the
Engine Control Module (ECM).

Cause

Potential turbocharger wastegate linkage wear.

Correction

If the complaint is a cold start rattle noise, put the car on a hoist and use the remote start
feature to start the vehicle while prepared to touch the wastegate actuator rod with a long
screwdriver.
– This rod is visible from under the vehicles near the catalytic converter.
• If during the cold start converter light off procedure, the rattle noise can be heard and
is then damped by touching the wastegate actuator rod with the screwdriver, then the
premature wastegate linkage wear is present and will likely be solved by replacing the
turbocharger. Refer to Compressor Air Intake Turbocharger Removal in the Service
Manual and Compressor Air Intake Turbocharger Installation in the Service Manual
• If DTC P0299 is set, refer to Service Information.

Copyright 2023 General Motors LLC. All Rights Reserved.

Page 2

August, 2023

Bulletin No.: 23-NA-058

Important: Service agents must comply with all
International, Federal, State, Provincial, and/or
Local laws applicable to the activities it performs
under this bulletin, including but not limited to
handling, deploying, preparing, classifying,
packaging, marking, labeling, and shipping
dangerous goods. In the event of a conflict between
the procedures set forth in this bulletin and the
laws that apply to your dealership, you must follow
those applicable laws.

Service Information
Check Vacuum Supply from the Vacuum Pump

5392518

1. Disconnect the Turbocharger Wastegate Actuator
Vacuum Control Solenoid Valve Hose (1) from the
Turbocharger Wastegate Regulator Solenoid
Valve.
2. Utilizing EN-23738-A Vacuum Pump with a integral
vacuum gauge, connect said pump to the
Turbocharger Wastegate Actuator Vacuum Control
Solenoid Valve Hose.
3. Engine at operating temperature at idle.
4. Verify the tool reading: EN-23738-A Vacuum Pump
= −50 kPa (−0.5 bar, 15 in Hg).
• If the desired pressure/vacuum cannot be
achieved or does not hold steady:
⇒ Ignition/Vehicle » Off.

⇒ Test or replace the component: Vacuum Pump
Assembly and related hoses.
• If the desired pressure/vacuum can be
achieved and holds steady:
• Engine » Off.
• Reconnect the Turbocharger Wastegate
Actuator Vacuum Control Solenoid Valve
Hose to the Turbocharger Wastegate
Regulator Solenoid Valve and refer to Check
Wastegate Vacuum Regulator Valve
Function.

Bulletin No.: 23-NA-058

August, 2023

Page 3

Check Wastegate Vacuum Regulator Valve
Function

5392518

1. Disconnect the Turbocharger Wastegate Actuator
Vacuum Tank Solenoid Valve Tub (2) from the
Turbocharger Wastegate Regulator Solenoid
Valve.
2. Connect the EN-23738-A Vacuum Pump to the
Turbocharger Wastegate Solenoid Valve Actuator
supply port.
3. Engine at operating temperature at idle.
4. Verify the tool reading: EN-23738-A Vacuum Pump
= Less than −17 kPa(−0.17 bar, 5 in Hg).
• If −17 kPa(−0.17 bar, 5 in Hg) or greater.
⇒ Test or replace the component: Turbocharger
Wastegate Regulator Solenoid Valve. Refer to
Turbocharger Wastegate Regulator Solenoid Valve
Removal in the Service Manual and Turbocharger
Wastegate Regulator Solenoid Valve Installation in
the Service Manual.
• If less than −17 kPa(−0.17 bar, 5 in Hg).
⇒ Engine Speed Greater than 5000 RPM — For 2 s.
⇒ Verify the tool reading: EN-23738-A Vacuum Pump
= Greater than −50 kPa(−0.5 bar, 15 in Hg).
• If less than−50 kPa(−0.5 bar, 15 in Hg).
⇒ Test or replace the component: Turbocharger
Wastegate Regulator Solenoid Valve. Refer to
Turbocharger Wastegate Regulator Solenoid Valve

Removal in the Service Manual and Turbocharger
Wastegate Regulator Solenoid Valve Installation in
the Service Manual.
• If Greater than −50 kPa(−0.5 bar, 15 in Hg).
The Turbocharger Wastegate Regulator
Solenoid Valve has been validated to be
functioning correctly and proceed to
Turbocharger Inspection.

Turbocharger Inspection
1. Remove the Turbocharger from the vehicle and
inspect the Turbocharger Wastegate linkage for
excessive wear/play. (Compare to replacement
Turbocharger if necessary).
⇒ Evaluate the external vacuum actuator
rod-link-end-to-arm for Inner arm (ID) to outer
pin (OD) clearance of more than approximately
1.5 mm clearance.
⇒ Look for significant ovalization of the arm hole
(more than 1.5 mm delta smallest to largest
clearance axis).
2. Inspect the wastegate-spindle to
turbine-housing-bushing for excessive clearance.
⇒ Evaluate based on ability to rock the
wastegate-spindle within the
turbine-housing-bushing significantly. Expect up
to ~ 2 degrees in normal wear range. Excessive

Page 4

August, 2023

movement may be a concern if greater than ~ 2
in one radial direction indicating excessive wear
(ovalization of bushing).
⇒ Take note if there is contact of the underside of
the rod-link-end-to-arm to the external top side
of the turbine casting (beyond the top of
bushing OD regular contact radius). This is a
clear indicator of excessive spindle to bushing
interface wear.
⇒ If any of the above conditions have been
verified, replace the Turbocharger. Refer to
Compressor Air Intake Turbocharger Removal
in the Service Manual and Compressor Air
Intake Turbocharger Installation in the Service
Manual.
3. Perform: Intake System Learned Values Reset.

Bulletin No.: 23-NA-058

Causal
Part

Description

Part
Number

Qty

N/A

GASKET,
CTLTC CONV

12641115

1

N/A

GASKET, TURBO
OIL RTN PIPE

55514397

2

N/A

GASKET, EXH
SYS FRT

13499082

1

N/A

NUT, TURBO

11612078

4

N/A

PIPE, TURBO
OIL FEED

55495320

1

N/A

WASHER,
TURBO OIL
FEED PIPE

55497445

1

N/A

SEAL, TURBO
OIL FEED PIPE

55487539

1

Parts Information
Note: Only select the parts that coincide with the repair
performed.
Causal
Part

Part
Number

Qty

VALVE, TURBO
WASTEGATE
REG SOL

55599331

1

TURBOCHARGER,
CMPR AIR INT

25204082

N/A

CLAMP,
EXH PIPE

55513359

1

N/A

HOSE, PCV VAC

55513554

1

N/A

GASKET, TURBO

55494843

1

X

X

Description

Warranty Information
For vehicles repaired under the Powertrain coverage,
use the following labor operation. Reference the
Applicable Warranties section of Investigate Vehicle
History (IVH) for coverage information.
Labor
Operation

Description

Labor Time

4023250

Turbocharger Wastegate
Regulator Solenoid Valve
Replacement

Use
Published
Labor Time

4088328*

Turbocharger Replacement

3.3 Hrs.

1

*This is a unique Labor Operation for Bulletin use only.

Version

2

Modified

Released March 30, 2023
Revised August 03, 2023 - Changed the Warranty Information from Emissions to
Powertrain coverage.

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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