warning GMC SIERRA 2023 User Guide

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Keys, Doors, and Windows 23
The engine will continue to run for
15 minutes. After 30 seconds, repeat
Steps 1 and 2 for a 15-minute time
extension.
Turn the ignition on to operate the vehicle.
Extending Engine Run Time
The engine run time can be extended by
15 minutes, for a total of 30 minutes,
if during the first 15 minutes Steps 1 and 2
are repeated while the engine is still
running. An extension can be requested
30 seconds after starting.
A maximum of two remote starts, or a
single start with an extension, is allowed
between ignition cycles.
The vehicle's ignition must be turned on and
then back off to use remote start again.
Canceling a Remote Start
To cancel a remote start, do one of the
following:
.Press and hold/until the parking lamps
turn off.
.Turn on the hazard warning flashers.
.Turn the ignition on and then off.
Door Locks
{Warning
Unlocked doors can be dangerous.
.Passengers, especially children, can
easily open the doors and fall out of a
moving vehicle. The doors can be
unlocked and opened while the vehicle
is moving. The chance of being thrown
out of the vehicle in a crash is
increased if the doors are not locked.
So, all passengers should wear seat
belts properly and the doors should be
locked whenever the vehicle is driven.
.Young children who get into unlocked
vehicles may be unable to get out.
A child can be overcome by extreme
heat and can suffer permanent injuries
or even death from heat stroke.
Always lock the vehicle whenever
leaving it.
.Outsiders can easily enter through an
unlocked door when you slow down
or stop the vehicle. Locking the doors
can help prevent this from happening. There are several ways to lock and unlock
the vehicle.
From outside:
.Use the Remote Keyless Entry (RKE)
transmitter.
.Use Keyless Access, if equipped.
.Use the key in the driver door or the
passenger door, if equipped.
From inside, use the power door locks or the
manual door locks. To lock the door with
the manual door locks, push down on the
manual lock knob.
From inside, pull the door handle once to
unlock the door. Pull the handle again to
open the door.
See Vehicle Alarm System 034.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
26 Keys, Doors, and Windows
When the safety lock is enabled, adults and
older children will not be able to open the
rear door from the inside. Cancel the safety
locks to enable the doors to open from the
inside.
To cancel the safety lock:1. Unlock the door and open it from the outside.
2. Move the lever up to unlock. Do the same for the other door.
Doors
Tailgate
Manual Tailgate
{Warning
It is extremely dangerous to ride on the
tailgate, even when the vehicle is
operated at low speeds. People riding on
the tailgate can easily lose their balance
and fall in response to vehicle maneuvers.
Falling from a moving vehicle may result
in serious injuries or death. Do not allow
people to ride on the tailgate. Be sure
everyone in your vehicle is in a seat and
using a seat belt properly. Use the key to unlock the tailgate.
Open the tailgate by lifting up on its handle
while pulling the tailgate down.
To shut the tailgate, firmly push it upward
until it latches.
After closing the tailgate, pull it back to be
sure it is latched securely.
Some tailgates have an electric latch. If the
battery is disconnected or has low voltage,
the tailgate will not open. The tailgate will
resume operation when the battery is
reconnected or recharged.
Power Release Tailgate
{Warning
Make sure there is no one in the way of
the power tailgate as it is opening and
closing, and keep hands away from the
tailgate hinges when in use. You or
others could be injured if caught in the
path of the power tailgate or tailgate
hinges.
Caution
To avoid damage to the tailgate, make
sure the area behind the tailgate is clear
before opening it.
In the case of a dead battery, the tailgate
can be opened manually. Contact your
dealer or Roadside Assistance.
If equipped, to lock or unlock the tailgate,
use the RKE transmitter or the key. See
Remote Keyless Entry (RKE) System
Operation (Key Access) 012 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 014.
The vehicle must be in P (Park).
To open the tailgate:
.Pressxtwice quickly on the RKE
transmitter until the tailgate moves.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Keys, Doors, and Windows 27
.Press5on the center stack.
.Press the touch pad on the tailgate
handle after unlocking all doors. Use the
top of the tailgate to pull against if
assistance is required. If equipped with
Keyless Access, a locked tailgate can be
opened if the RKE transmitter is within
1 m (3 ft).
To close the tailgate, firmly push it upward
until it latches. Pull it back to be sure it is
latched securely.
Power Tailgate
{Warning
Make sure there is no one in the way of
the power tailgate as it is opening and
closing, and keep hands away from the
tailgate hinges when in use. You or
others could be injured if caught in the
path of the power tailgate or tailgate
hinges.
Caution
To avoid damage to the tailgate, make
sure the area behind the tailgate is clear
before opening it. If equipped with a power open/close
tailgate, the tailgate can be opened or
closed in several ways. To open the tailgate,
do one of the following:
.Pressxtwice quickly on the RKE
transmitter until the tailgate moves. See
Remote Keyless Entry (RKE) System
Operation (Key Access) 012 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 014.
If equipped with Keyless Access, a locked
tailgate can be opened if the RKE
transmitter is within 1 m (3 ft).
.Press5on the center stack.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
28 Keys, Doors, and Windows
.Press the touch pad on the tailgate
handle after unlocking all doors.
To close the tailgate, do one of the
following:
.Pressxon the RKE transmitter once,
then quickly press and hold
xuntil the
tailgate completely closes. If
xis
released prior to it being fully closed, the
tailgate will reopen.
.Press and hold5on the center stack
until the tailgate is fully closed. If
5
is released prior to the tailgate being
fully closed, it will reopen. A chime will
sound when the tailgate is fully closed.
.Press the touch pad on the tailgate
handle.
A chime sounds and the taillamps flash
during the closing operation. If the warning
chime is not functioning, the tailgate will
not power close. Power opening is still
enabled. See your dealer for service.
The power tailgate may be temporarily
disabled after repeated power cycling over a
short period of time. If this occurs, the
tailgate can still be operated manually.
The vehicle must be in P (Park) to operate
the power tailgate. If the vehicle is shifted
out of P (Park) while the power function is
in progress, the tailgate will continue to
completion. If the vehicle is accelerated
while the tailgate is still closing, the tailgate
may stop and reverse direction. Make sure
the tailgate is closed and latched before
driving. Lift-to-Close Operation
To close the tailgate using the lift-to-close
feature, lift the tailgate from the full-open
position to at least 10 cm (4 in) and hold it
momentarily. Then, the tailgate will start
closing automatically. If the tailgate is lifted
more than halfway between open and close,
then it will not close automatically.
Obstacle Detection
If the tailgate encounters an obstacle during
a power open cycle, it will stop on the
obstacle. After removing the obstruction, the
tailgate can be allowed to open. If the
tailgate encounters an obstacle during the
closing cycle, it will stop and reverse to
full open.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Keys, Doors, and Windows 29
If the tailgate encounters multiple obstacles,
the power function will deactivate. After
removing the obstructions, manually close
the tailgate to resume normal power
operation.
Manual Operation
The tailgate can be manually closed from
the full-open position when the tailgate is
lifted in a continuous motion. If the tailgate
motion is stopped between the full-open
and half-closed positions, the lift-to-close
feature can engage and power close the
tailgate. If the touch pad is pressed during
power operation, the tailgate will stop and
allow manual operation. The tailgate must
be held after stopping, or it will continue
to open.
MultiPro Tailgate
{Warning
Make sure there is no one in the way of
the power tailgate as it is opening and
closing, and keep hands away from the
tailgate hinges when in use. You or
others could be injured if caught in the
path of the power tailgate or tailgate
hinges.
Caution
To avoid damage to the tailgate, make
sure the area behind the tailgate is clear
before opening it.
If equipped with this feature, the vehicle
must be in P (Park).
Switches in the inner tailgate prevent the
primary tailgate from being opened when
the inner tailgate is not fully closed. To open the primary tailgate:
.Pressxtwice quickly on the RKE
transmitter until the tailgate moves. See
Remote Keyless Entry (RKE) System
Operation (Key Access) 012 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 014.
If equipped with Keyless Access, the
tailgate can be opened if the RKE
transmitter is within 1 m (3 ft).

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Keys, Doors, and Windows 31
MultiPro Inner Tailgate Enable/Disable
The MultiPro inner tailgate may be equipped
with an enable/disable feature to prevent
the inner tailgate from being opened when
a hitch or other equipment is installed that
could damage the inner tailgate.
To disable the inner tailgate from opening:
ensure that the remote key is within
1 meter (3 ft) of the rear bumper and then
hold the upper touchpad on the tailgate
handle for three seconds. The tail lamps will
flash to alert you that the inner gate has
been disabled. The inner and outer tailgate
can still be operated like a traditional
tailgate, but the inner gate will not be able
to be opened alone.To enable the inner tailgate function, hold
the upper touchpad on the handle for
3 seconds until the tail lamps flash. The
inner tailgate can now be opened separately
from the outer tailgate.
Tailgate Step
{Warning
To avoid personal injury, keep hands
away from the hinges when operating
the tailgate step.
With the primary and inner tailgates open,
the tailgate step can be lowered to access
the pickup bed.
Using the Step
Caution
When using the tailgate as a step, the
load rating is 170 kg (375 lb), which
includes a person and cargo. Overloading
the tailgate step can cause damage to
the tailgate system.
.To lower the tailgate step, press the
button at the center of the step. Make
sure it lowers to the fully open position.
.To close the tailgate step, lift it firmly.
Make sure that both side latches are
engaged.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Keys, Doors, and Windows 33
Transporting Items That Can
Catch Fire
{Warning
To avoid personal injury and/or vehicle
damage when transporting items that
can catch fire, such as leaves, mulch, hay,
or cardboard, in the truck bed:
.Make sure items are securely
contained inside the truck bed. Never
allow them to hang over the sides or
fall in between the truck bed and
the cab.
.Never place items between the cab
and the truck bed. They could touch
hot exhaust parts and ignite.
{Warning
Keep cigarettes, sparks, and other ignition
sources away from the area between the
bed of the truck and cab. They could fall
onto the fuel system below and start a
fire. You or others could be injured and/
or the vehicle damaged.
Power Assist Steps
{Warning
To avoid personal injury or property
damage, before entering or exiting the
vehicle, be sure the power assist step is
fully extended. Do not step on the power
assist step while it is moving. Never place
hands or other body parts between the
extended power assist step and the
vehicle.
If equipped, the power assist steps will
deploy when the door is opened and
automatically retract three seconds after the
door is closed. The power assist steps will
retract immediately if the vehicle starts
moving. Check the step position before
exiting the vehicle.
Disable the power assist steps before jacking
or placing any object under the vehicle.
Too much ice buildup may prevent
deployment of the power assist steps. If this
happens, disable the power assist steps,
clear the ice, then enable the assist steps
and confirm normal function prior to use. Keep hands, children, pets, objects, and
clothing clear of the power assist steps
when in motion. The steps will reverse
direction if they encounter an obstruction
when opening or closing. Remove the
obstruction, then open and close the door
on the same side to complete the motion of
the assist steps. If the obstruction is not
cleared, the assist steps remain extended
while driving.
Extend or retract both power assist steps for
cleaning through the vehicle settings menu.
To view available settings from the
infotainment screen, touch Settings >
Vehicle > Comfort and Convenience.
Enable/Disable
The power assist steps can be enabled or
disabled through the vehicle settings menu.
To view available settings from the
infotainment screen, touch Settings >
Vehicle > Comfort and Convenience.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
36 Keys, Doors, and Windows
located in the center console. SeeRemote
Keyless Entry (RKE) System Operation (Key
Access) 012 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 014.
If the ignition mode will not change with
the other transmitter or with the
transmitter in the transmitter pocket, your
vehicle needs service. If the ignition does
change modes, the first transmitter may be
faulty. See your dealer who can service the
theft-deterrent system and have a new RKE
transmitter programmed to the vehicle.
It is possible for the immobilizer system to
learn new or replacement RKE transmitters.
Up to eight transmitters can be
programmed for the vehicle. To program
additional transmitters, see "Programming
Transmitters to the Vehicle" under Remote
Keyless Entry (RKE) System Operation (Key
Access) 012 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 014
Do not leave the transmitter or device that
disarms or deactivates the vehicle theft
system in the vehicle. When equipped with a key, if the engine
still does not start, and the key appears to
be undamaged, try another ignition key.
It may be necessary to check the fuse. See
Fuses and Circuit Breakers
0329. If the
engine still does not start with the other
key, the vehicle needs service. If the vehicle
does start, the first key may be faulty. See
your dealer. It is possible for the
immobilizer system to learn new or
replacement keys. Up to eight keys can be
programmed for the vehicle. To program
additional keys, see Keys (Key Access)08or
Keys (Keyless Access) 011. Do not leave the
key or device that disarms or deactivates
the vehicle theft system in the vehicle.
See your dealer to get a new key blank cut
exactly as the ignition key that operates the
system.Exterior Mirrors
Convex Mirrors
{Warning
A convex mirror can make things, like
other vehicles, look farther away than
they really are. If you cut too sharply
into the right lane, you could hit a
vehicle on the right. Check the inside
mirror or glance over your shoulder
before changing lanes.
Standard Mirrors
The passenger side mirror is convex shaped.
A convex mirror surface is curved so more
can be seen from the driver seat.
Trailer-Tow Mirrors
The upper portion of both the driver and
passenger mirrors is flat.
The lower portion of both the driver and
passenger mirrors is convex. A convex mirror
surface is curved so more can be seen from
the driver seat. The lower portion is
adjusted manually.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
42 Keys, Doors, and Windows
The adjustment options are:
.Brightness
.Zoom
.Tilt
{Warning
The Rear Camera Mirror (RCM) has a
limited view. Portions of the road,
vehicles, and other objects may not be
seen. Do not drive or park the vehicle
using only this camera. Objects may
appear closer than they are. Check the
outside mirrors or glance over your
shoulder when making lane changes or
merging. Failure to use proper care may
result in injury, death, or vehicle damage.
Troubleshooting

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
44 Keys, Doors, and Windows
Once the horizontal guideline is in the
desired location, press and hold the button
for another three seconds and repeat the
above step for the vertical guideline
programing. To readjust the horizontal
location of the guidelines after adjusting the
vertical location, press and hold the button
for three seconds.
After eight seconds since the last button
press, the position of the guidelines is
locked into memory.
Windows{
Warning
Never leave a child, a helpless adult, or a
pet alone in a vehicle, especially with the
windows closed in warm or hot weather.
They can be overcome by the extreme
heat and suffer permanent injuries or
even death from heat stroke.
The vehicle aerodynamics are designed to
improve fuel economy performance. This
may result in a pulsing sound when either
rear window is down and the front windows
are up. To reduce the sound, open either a
front window or the sunroof, if equipped.
Manual Windows
If equipped, turn the hand crank on each
door to manually raise or lower the manual
windows.
Power Windows
{Warning
Children could be seriously injured or
killed if caught in the path of a closing
window. Never leave the Remote Keyless
Entry (RKE) transmitter or keys in a
vehicle with children. When there are
children in the rear seat, use the window
lockout button to prevent operation of
the windows. See Keys (Key Access)08
or
Keys (Keyless Access) 011.