File in Section:

Service Bulletin

Bulletin No.:
Date:

PIC5836C
February, 2014

PRELIMINARY INFORMATION
Subject:

Rattle Or Buzz Noise From Rear Speaker Or Speakers - Worse With High Bass Levels

Models:

2013 - 2014 Cadillac ATS
This PI was superseded to add the 2014 model year. Please discard PIC5836B.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern
Some customers may comment on a rattle or buzz noise from the rear speakers. The noise may be more easily
duplicated with the Bass set to higher levels.
The rear speaker(s) generally is NOT the cause of this issue. Possible causes include:
1. Improper speaker mounting or loose trim, wiring harnesses, or other parts may cause an audible buzz or
distortion.
2. Rattle or buzz from the OnStar module.
3. Seat belt retractor buzz - Center seat belt retractor bolt may be contacting decklid torque rod inside trunk
causing metallic rattle.
4. Child tether cover may be loose in package shelf trim.
5. Package shelf trim and / or trunk upper trim plastic Christmas tree fasteners may buzz to shelf at attachment
holes.
6. Leading edge of package shelf, behind rear seat back.
7. Package shelf "J” hooks loose.

Recommendation/Instructions
The EL-50334-6 Audio System Diagnostic CD contains audio tracks that can be used to duplicate and isolate such
concerns. Tracks 11 and 12 contain audio sweep tones for testing for speaker and grill rattles.
1. Inspect the rear speaker and the surrounding interior trim for proper and secure mounting. If the speaker trim
has come loose, replace the speaker. If surrounding interior trim is found to be loose or improperly secured,
correctly secure the item and add foam to insulate items as needed. Add foam to the subwoofer speaker
connector to prevent contact to the under shelf trim from making contact. Use ½” by 5/16” of Kent Adhesive
Backed Shim Stock (foam) P/N P40125 or equivalent.

3627512

3632284

2. OnStar module - place 1/4" foam pad underneath the module (if foam is not currently in place). Use (4) 1” x 6”x
5/16” thick strips of Kent Adhesive Backed Shim Stock (foam) P/N P46510 or equivalent.
Note: Do not apply foam the beyond the base of the module, avoid adding the foam in the area of the mounting
flanges.

3627511

3. Seat belt retractor buzz - Ensure the existing foam torsion spring cover is centered on the deck lid torque
rods. Use a zip tie to secure. Add a piece of 3/8” rubber hose (fuel line) to the center belt rear mounting bolt.
See pictures below. Note hose on seat belt bolt left side behind torsion spring.

3627504

3627505

3629698

4. Add felt onto the package shelf trim opening to prevent movement between the trim and the child seat tether
cover if the felt is not present. Use Kent Adhesive Backed Flocking Tape P/N KT13295 or equivalent see
pictures below.

3630391

5. Add foam grommets onto each of the Christmas tree fasteners (if not present) prior to reinstalling back into the
package shelf sheet metal holes. Use 1” X 1” block of Kent Adhesive Backed Shim Stock P/N P46510 or
equivalent to create a foam washer(s) as needed. Fold the 1” x1” block over from corner to corner and carefully
cut a hole in the center of the block to create a washer/spacer, see pictures below.

3627502

3627503

6. Add two ¾” by 1 1/2 “ long by 7/16” thick of Kent Adhesive Backed Shim Stock (foam) P/N P46505 or equivalent
centered between the retaining clips on the leading edge of the package shelf (behind/under the rear seat back)
see picture below.

3627506

7. Check the “J” hooks of the package shelf cover/trim for being secure. See picture below. Use hot glue to
resecure the “J” hooks as needed.

3627509

Warranty Information
The correction for this concern may be one of several repairs described above. For vehicles repaired under
warranty, please use the appropriate warranty labor operation based on the actual cause and repair.
Labor Operation

Description

Labor Time

3480038*

Audio System Diagnostics Using EL-50334-6
Audio System Diagnostic CD

0.2 hr

Add

To Remove Rear Package Shelf Trim

1.2 hr

Add

Add Foam to Rear Speaker and/or Surrounding
Trim (After Rear Shelf Trim Removed)

0.2 hr

Add

Install Foam Pad Underneath the Onstar Module
(After Rear Shelf Trim Removed)

0.2 hr

Add

Add Foam Grommets Onto Each of the Christmas
Trees For the Rear Package Shelf (After Rear
Shelf Trim Removed)

0.2 hr

Add

Add Felt Onto the Package Shelf Trim Opening

0.2 hr

Add

Add Rubber Hose to End of Bolt

0.1 hr

* This is an unique labor operation for bulletin use only. This will not be published in the Labor Time Guide.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is
resolved without completing every step, the remaining steps do not need to be performed.