Bulletin No.:

Service Bulletin

Date:

24-NA-028
February, 2024

INFORMATION
Subject:

Power Tonneau Cover Diagnostic Tips

Brand:

Model:

GMC

HUMMER EV Pickup

Model Year:

VIN:

from

to

from

to

2022

2024

-

-

Engine:

Transmission:

All

All

Involved Region or Country

United States and Canada

Additional Options (RPOs)

With Accessory Power Tonneau Cover part number 86575628 or 86595165

Condition

Some customers may comment on the tonneau cover not operating properly.

Correction

Review the following diagnostic aids shown below

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.
Important: This technical service bulletin (TSB) can
only be completed by certified repair facilities who have
met all specific training, tool and equipment
requirements pertaining to the vehicle Brand and Model
serviced. Repairs must be performed by a technician
who has successfully completed the required training.

•

Use tape to hold the top lip seal of the side rail
during the installation of the side rail to the
canister. Folded over side rail lip seal will cause
the system to go into an unwanted
anti-pinch mode.

Pre-Installation Assistance
•
•
•

Links to installation videos can be found in SI
DOC ID 6152455, Pickup Box Cover Package
Installation (Power Tonneau Cover).
Always disconnect the 12v battery during
installation. Failure to disconnect the 12V can lead
to a blown fuse or module logic lockup.
Care must be observed with all wires. Poor wiring
can lead to shorts in the system.
• Avoid any exposed or unsealed wires after
splicing to the vehicle.
• All connectors are securely locked in place.
• Use caution during tonneau cover positioning
to avoid pinched wires.

Copyright 2024 General Motors LLC. All Rights Reserved.

6544195

Note: The above illustration shows what happens
when the lip seal is under the cover during installation
(A). The lip seal (B) is wavy due to incorrect assembly.
The seal must be on top of the cover, not the cover.
This will cause binding resulting in anti-pinch mode
activation.

Page 2

February, 2024

Bulletin No.: 24-NA-028

Note: During initial installation on a flat surface or
protected table, tape back the seal surfaces on the front
4in. (100mm) of each rail using masking tape, as
shown. This will protect them from damage during
install.

6540967

•
•

Keep side rail tracks clean and apply silicon spray
as needed.
Add silicon spray to drum springs as directing in
the owner’s manual or SI DOC 6152455.

6540966

•

Width of the side rails must not exceed
recommended distance of 63.25”. Wide rails
prevent the cover from contacting the limit
switches during calibration and causes a fault with
a flashing light. Details for addressing wide rails
can be found in the troubleshooting section of SI
DOC ID 6152455, Pickup Box Cover Package
Installation (Power Tonneau Cover). It might be
necessary to adjust the side rails even closer than
the 63.25” dimension at the tail gate location.

Tonneau Cover Binds or Excessively
Noise
•

Begin by manually sliding the cover in both
directions. Pressing the clutch button on the motor
allows for the tonneau cover to slide freely. Do this
to aid with inspecting for binding. The clutch
button should be checked to be fully extended
prior to calibration/operation.

6540968

•

Tonneau cover will make more noises during
electric operation, especially in cold weather,
compared to manual inspection. If noise is
combined with noticeable binding, lubricate tracks
and drum springs with silicon spray.

Bulletin No.: 24-NA-028

February, 2024

Page 3

Completely Inoperative
•

If the 12V battery has dropped below 9 volts, the
cover will need to be re-calibrated to regain
functionality.
Note: If the vehicle's 12v battery was disconnected for
service or dropped below 9 volts while in service,
re-calibrate the tonneau cover before giving the vehicle
back to the customer.
•

•

Always attempt to re-calibrate the system first by
following the directions in the owner’s manual,
installation instructions, and GMC support
website.
• If the motor clutch button has been
disengaged, or the vehicle battery has been
disconnected, complete the calibration before
the next electric operation.
2.1.
Press (Unlock) twice on the remote
key to unlock the cover.
2.2.
Open the tailgate.
2.3.
Ensure the motor clutch button is
engaged and pulled out completely .
2.4.
Ensure the doors are unlocked and the
driver door is open to disable
auto-locking during calibration
procedure.
2.5.
Press the two side rail buttons
simultaneously for 10 seconds to start
calibration mode.
2.6.
The cover will open and close twice
automatically. The cover internal LED
light will pulse slowly during calibration
and stop pulsing when the calibration
is complete. If the light does not turn
on, remove the tonneau fuse located in
the Instrument Panel Fuse Block (Left)
for five seconds. See “Left” in
Instrument Panel Fuse Block (Right)
Instrument Panel Fuse Block (Left).
Reinstall the fuse and re-calibrate the
tonneau cover. Replace the fuse if the
lights do not come on during
re-calibration.
If the power and grounds check OK, inspect the
in-line connector at the motor to verify proper
connection.

6540969

•
•

Inspect the motor for any leakage. If any visible
brown substance is found, replace the motor p/n
85597137.
Check for power and ground at the X1 connector
located at the power tonneau cover control
module. Refer to SI DOC 6012295. If necessary,
inspect the 4 wires connected to the main body
wire harness under the left rear wheel well. Poorly
installed and sealed splice connectors have been
discovered and will cause electrical issues.

6540970

•

Showing the location of 4 wires in the main body
wire harness that must be connected to the power
tonneau cover asm. Inspect the wire-to-wire splice
connectors for proper sealing and crimping.
Inspect the open/close button and limit switches
for opens or shorts utilizing the schematics found
in SI DOC ID 6012539, Power Tonneau Cover
Schematics.

Page 4

February, 2024

Bulletin No.: 24-NA-028

Additional References
The following are resources available to aid in the
installation and diagnostics of the power tonneau cover.
• SI DOC ID 6152455, Pickup Box Cover Package
Installation (Power Tonneau Cover)
• SI DOC ID 6152455, Section 4 Troubleshooting
(found at the end of the document)
• SI DOC ID 6012539, Power Tonneau Cover
Schematics
• SI DOC ID 5914698, Power Tonneau Cover
Malfunction
• SI DOC ID 6214953, Power Tonneau Cover
Calibration
• https://www.gmc.com/support/vehicle/
storage-doors-windows/power-tonneau/
troubleshooting
•

Warranty Classification
Important: When filing warranty claims for power
tonneau cover repairs, use the labor codes found in the
Dealer Installed GM Accessory Repairs section of the
labor time guide.
Use either:
• 0522230 Pickup Box Tonneau Cover Repair
• 0522232 Pickup Box Tonneau Cover Adjustment

Version

1

Modified

Released February 08, 2024

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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