Service Bulletin

Bulletin No.:

21-NA-017

Date:

May, 2021

TECHNICAL
Subject:

Rattle or Creak Noise Heard Coming From Driver Left Rear Quarter Panel Area When
Driving Over Bumps

Brand:

Model:

Chevrolet

Trailblazer (VIN M)

Involved Region or Country

Model Year:
from

to

2021

2021

VIN:
from

Engine:

Transmission:

All

All

to

North America,

Additional Options (RPOs)
Condition

Some customers may comment on a rattle or creak noise heard coming from the driver
left rear quarter panel area when driving over bumps.
The noise may travel around the B and C-pillars, and is best heard from behind the driver.

Cause

The cause of the condition may be a quality issue of inefficient and/or mis-located spot
welds at the C-pillar upper, inner structure panels.

Correction

Upon verifying the Condition, drill 3 holes through ONLY the C-pillar upper, inner structure
and Mig weld the hole locations following the steps in the Service Procedure below.

Service Procedure
1. Disable the SIR system. Refer to SIR Disabling
and Enabling, in SI.

5721193

2. Remove the headliner and left rear row seat roof
rail airbag. Refer to Front and Rear Row Roof Rail
Airbag Replacement, in SI.

Copyright 2021 General Motors LLC. All Rights Reserved.

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May, 2021

Bulletin No.: 21-NA-017

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3. Locate the 3 forward - most spot weld and hole
locations, and mark drill locations, approximately
10 mm (0.40 in) (1) forward of them.

5721197

5. De-burr and prep the inner panel for Mig welding.
5721196

4. Using an 8mm (5/16 inch) drill bit, drill through
ONLY the inner sheet metal panel at those 3
locations.

Bulletin No.: 21-NA-017

May, 2021

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6. Mig weld the drilled hole areas.

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5721202

7. Apply *SEM cavity wax to the inside of the inner
panel, and *SEM EzCOAT to the outside of the
inner panel.
8. Road test the vehicle, to ensure the noise has
been eliminated.

5721203

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May, 2021

Bulletin No.: 21-NA-017

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9. Reinstall the left rear row seat roof rail airbag (3)
and the headliner. Refer to Front and Rear Row
Roof Rail Airbag Replacement, in SI.
10. Enable the SIR system. Refer to SIR Disabling and
Enabling, in SI.
* We believe this source and their products to be
reliable. There may be additional manufacturers of
such products/materials. General Motors does not
endorse, indicate any preference for, or assume any
responsibility for the products or material from this firm
or for any such items that may be available from other
sources.

Parts Information
For ordering adhesive material, contact SEM Customer
Care at #866–327–7829, or
[email protected], or at SEM Tech Support
at #800-831-1122, or [email protected].
Causal
Part

N/A

Description

Part
Number

SEM - Rust
Preventor
Cavity Wax

39573

SEM - EzCOAT

62233

Qty

As needed

Bulletin No.: 21-NA-017

May, 2021

Page 5

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

Description

Labor Time

1481488*

Drill and Mig Weld Left C-Pillar Inner Structure

2.3 hr

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

Version

2

Modified

Released January 27, 2021.
Revised May 19, 2021 – Added Additional Weld Location to Service Procedure, Road
Test and Increased Labor Time.

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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