Bulletin No.:

Service Bulletin

Date:

20-NA-044
March, 2020

TECHNICAL
Subject:

Brand:

Endgate Will Not Auto Open or Auto Close After Accessory Tonneau Cover Installation,
and/or Poor Fit of Tonneau Cover to Endgate
Model:

Model Year:

VIN:

from

to

2019

2019

from

Engine:

Transmission:

All

All

to

Silverado
1500 (New
Model)
Chevrolet

GMC

Silverado
1500 (New
Model - 12th
VIN Digit =
7) - 4WD
Sierra 1500
(New Model)
Silverado
1500

Chevrolet

Silverado
2500HD/
3500HD

2020

2020

Sierra 1500
GMC

Sierra
2500HD/
3500HD

Involved Region or Country

North America

Additional Options (RPOs)
Condition

Copyright 2020 General Motors LLC. All Rights Reserved.

Some customers may comment that after installation of accessory tonneau cover, the
endgate will fail to auto open or auto close.

Page 2

March, 2020

Bulletin No.: 20-NA-044

Cause

5527998

The cause of the condition may be by excessive interference between the endgate and
the tonneau cover.
Adjust the tonneau cover can following the steps in the Service Procedure below.
• If the tonneau cover is a GM accessory, follow the adjustment procedures in the
Service Procedure below. GM tonneau covers are only the listed part numbers in the
tables below.
• If the tonneau cover is non-GM (IBP), contact the manufacturer of cover for specific
adjustment instructions. Non-GM tonneau covers can be identified by non-GM
branding. Contact information for the manufacture can be found with the installation
instructions provided with the kit, or by searching the part number in the Electronic
Parts Catalog.

Correction

Service Procedure
Note: The procedure provides instructions to position
the tonneau cover forward and upward, to reduce
compression at the endgate interface and is applicable
to the following part numbers.
GM Accessories Hard Tri Fold Tonneau Cover (VOZ)
84679033

84679034

84791287

84786353

84786354

84786355

GM Accessories Soft Tri Fold Tonneau Cover (63B)
84791288

84815933

84815934

84815929

84815930

84815931

84815932

Bulletin No.: 20-NA-044

March, 2020

Page 3

Verify Condition is Tonneau Cover Related
Some vehicles, which have a tonneau cover installed,
may be affected by a similar Condition, however the
Cause and Correction are completely different from this
bulletin. On these vehicles, it will be necessary rule out
the pickup box endgate lock actuator as the possible
Cause of the condition:
1. Open the rear end panel of the tonneau cover.
2. Cycle the power tailgate 5 times using push button
activation for auto open and auto close.
• If the power endgate DOES function properly,
then continue on and complete the tonneau
adjustment outlined in this bulletin.
• If the power endgate still DOES NOT function
properly, DO NOT proceed with this bulletin
repair, but move on to Bulletin # 20–NA-040
and complete the pickup box endgate lock
actuator replacement procedure.

Remove Tonneau Cover Assembly
1. Open the tonneau cover to the full open position
and secure with stowage straps.
2. Locate the forward clamp on the side rails.
3. Using an 11mm wrench, loosen the clamp nut,
while holding the hand knob to prevent the clamp
bolt from releasing.

5527999

Note: The clamps noted above are examples of the,
Hand Knob Style (1), Newer Version (2) and Soft
Tri-fold (3).
4. Loosen hand knob of the clamp. (Knob is on Hard
Tri-fold Only).
5. Slide the clamp assembly inboard to release the
clamp from the pickup box.
6. If installed, disconnect the safety tether.
7. Repeat steps #2 - 6 on the opposite side.
8. Remove the tonneau cover assembly.

Adjust Side Rail Upward and Forward
1. Starting on either side, using a T30 Torx wrench,
loosen the 6 bolts that attach the tonneau cover
side rail to the pickup box.
2. Remove the fastener located closest to the
tailgate.
3. Apply Loctite 242 to the fastener.
4. Push the side rail forward and upward from the
rear, and hold in position while completing step #5.
5. Tighten the rearward most fastener to 8.7 N*m
(77 lb in).
6. Remove the fastener located closest to the cab.
7. Apply Loctite 242 to the fastener.

Page 4

March, 2020

8. Lift the side rail at the front end, and hold in
position while completing step #9.
9. Tighten the forward most fastener to 8.7N*m.
(77 lb in).
10. Moving back-to-front in the pickup box, add thread
locker and tighten the remaining fasteners to 8.7
N*m (77 lb in).
11. Repeat steps #1-10 for the opposite side.

Reinstall Cover with Clamps Forward in
Notched Interface
1. Place the tonneau cover panels onto the
pickup box.
2. Verify the cover is centered side to side on the
tonneau rails.
3. Position a forward clamp into the notch in the
side rail.
4. Verify the clamp is completely engaged to the
tonneau cover side rail, pickup box molding, and
the pickup box metal. This is NOT applicable to
newer versions that attached directly to the
tonneau cover side rail.
5. Using the hand knob (or nut for newer versions and
soft tri-folds), snug tighten the tonneau cover
clamps to the side rail/pickup box.
6. Verify the clamps are completely forward in the
notch interface of the pickup box. If it is not, adjust
the clamp accordingly.
7. Verify that the clamp bolts are straight with respect
to cross bar to prevent pulling the tonneau cover
forward or rearward during final tightening. If it is
not, position the panel as needed, while keeping
the clamp in the location from steps #3 and 4.

Bulletin No.: 20-NA-044

8. Tighten both hand knobs until clamp is secure,
which should be 2-4 additional turns. Newer
versions and soft tri-folds that do not have the hand
knobs, may skip this step.
Caution: Excessive tightening may cause damage to
the bolt, clamp or tonneau cover.
9. Install the clamp nut and tighten to 8.7 N*m (77 lb
in). Hold the hand knob while tightening to prevent
it from spinning to over tightening the clamp. New
versions and the soft tri-fold do not add second nut,
only tighten nut installed during step #4.
10. Close the tonneau cover.
11. Cycle the power liftgate 5 times, to verify the issue
is resolved. If issue is not corrected with
adjustment, contact TAC for further assistance.
12. Open and close the front panel to verify the latches
have efficient engagement. If further adjustments
are necessary, reference the Hard Tri Fold Cover
Instruction Sheet #84786360.

Parts Information
No parts are required for this repair.

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.

GM Tonneau Covers
Labor Operation

Description

Labor Time

0580468*

Tonneau Cover Adjustment

0.5 hr

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

NON- GM (IBP) Tonneau Covers
Labor Operation

Description

Labor Time

0602708

Tonneau Cover Adjustment

0.5 hr

Bulletin No.: 20-NA-044

March, 2020

Page 5

Reference Section
Original Hard Tonneau Cover Instruction Sheet

5528001

Version

1

Modified

Released February 28, 2020

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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