2021 GMC YUKON warning

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Keys, Doors, and Windows 19
Press the button (2) above the license plate
to open the liftglass, or press
ctwice
quickly on the remote key. Do not leave the
liftglass open when raising the liftgate.
There will be a delay in the release of the
liftglass if there is an attempt to open it
while the rear wiper is in motion.
Use the pull cup to lower and close the
liftgate. Do not press the touch pad while
closing the liftgate. This will cause the
liftgate to be unlatched.
The liftgate can be opened when locked if
the remote key is within 1 m (3 ft) of the
touch pad. See Remote Keyless Entry (RKE)
System Operation 08.
The liftgate has an electric latch. If the
battery is disconnected or has low voltage,
the liftgate will not open. The liftgate will
resume operation when the battery is
reconnected and charged.
Power Liftgate Operation
{Warning
You or others could be injured if caught
in the path of the power liftgate. Make
sure there is no one in the way of the
liftgate as it is opening and closing.
Caution
Driving with an open and unsecured
liftgate may result in damage to the
power liftgate components.
If equipped, the power liftgate switch is on
the overhead console. The vehicle must be
in P (Park).
The modes are:
MAX : Opens to maximum height.
3/4 : Opens to a reduced height that can be
set from 3/4 to fully open. Use to prevent
the liftgate from opening into overhead
obstructions such as a garage door or
roof-mounted cargo. The liftgate can be
opened manually all the way.
OFF : Opens manually only.
To power open or close the liftgate, select
MAX or 3/4 mode and then:
.Pressbtwice quickly on the remote
key until the liftgate moves.
.Press8on the overhead console. The
driver door must be unlocked or locked
without the security armed.
.Press the touch pad on the underside of
the liftgate handle after unlocking all
doors. A locked vehicle can be opened if
the remote key is within 1 m (3 ft) of the
touch pad.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Keys, Doors, and Windows 25
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.
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. Check the step
position before exiting the vehicle. 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.
To extend or retract both power assist steps
for cleaning, see
Vehicle Personalization
0 126.
Enable/Disable
To enable or disable the power assist steps,
see Vehicle Personalization 0126.
Vehicle Security
This vehicle has theft-deterrent features;
however, they do not make the vehicle
impossible to steal.
Vehicle Alarm System
The indicator light, on the driver door near
the window, indicates the status of the
system. See Power Door Locks 016
Arming the Alarm System
1. Turn off the vehicle.
2. Lock the vehicle in one of three ways:
.Use the remote key.
.Use the Keyless Access system.
.With a door open, pressQon the
interior of the door.
3. After 30 seconds the alarm system will arm, and the indicator light will begin to
slowly flash. Pressing
Qon the remote

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
28 Keys, Doors, and Windows
The immobilization system is disarmed
when the ignition is turned on or to ACC/
ACCESSORY and a valid remote key is
present in the vehicle.
The security light, in the instrument cluster,
comes on if there is a problem with arming
or disarming the theft-deterrent system.
The system has one or more remote keys
matched to an immobilizer control unit in
the vehicle. Only a correctly matched
remote key will start the vehicle. If the
remote key is ever damaged, you may not
be able to start your vehicle.
When trying to start the vehicle, the
security light may come on briefly.
If the engine does not start and the security
light stays on, there is a problem with the
system. Turn the ignition off and try again.
If the vehicle will not change ignition modes
(ACC/ACCESSORY, on, off), and the remote
key appears to be undamaged, try another
remote key. Or, you may try placing theremote key in the backup location. See
Remote Keyless Entry (RKE) System
Operation
08.
If the ignition modes will not change with
the other remote key or in the backup
location, the vehicle needs service. If the
ignition does change modes, the first
remote key may be faulty. See your dealer.
It is possible for the immobilizer system to
learn new or replacement remote keys. Up
to eight remote keys can be programmed
for the vehicle. To program additional
remote keys, see “Programming Remote
Keys to the Vehicle” underRemote Keyless
Entry (RKE) System Operation 08.
Do not leave the remote key or device that
disarms or deactivates the theft-deterrent
system in the vehicle.
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 (Continued)
Warning (Continued)
into the right lane, you could hit a
vehicle on the right. Check the inside
mirror or glance over your shoulder
before changing lanes.
The passenger side mirror is convex shaped.
A convex mirror's surface is curved so more
can be seen from the driver seat.
Power Mirrors
To adjust the mirrors: 1. Press
}or|to select the driver or
passenger side mirror. The indicator light
comes on.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
32 Keys, Doors, and Windows
.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
See your dealer for service if a blue screen
and
3are displayed in the mirror, and
the display shuts off. Also, push the tab as
indicated to return to the automatic
dimming mode.
The Rear Camera Mirror may not work
properly or display a clear image if:
.There is glare from the sun or headlamps.
This may obstruct objects from view.
If needed, push the tab to turn off the
display.
.Dirt, snow, or other debris blocks the
camera lens. Clean the lens with a soft
damp cloth, or, if equipped, with the Rear
Camera Washer. See Rear Window Wiper/
Washer 098.
.The camera’s mounting on the vehicle has
been damaged, and/or the position or the
mounting angle of the camera has
changed.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Keys, Doors, and Windows 33
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.
Power Windows
{Warning
Children could be seriously injured or
killed if caught in the path of a closing
window. Never leave the remote key in a
vehicle with children. When there are (Continued)
Warning (Continued)
children in the rear seat, use the window
lockout switch to prevent operation of
the windows. SeeKeys07.
The power windows work when the ignition
is on, in ACC/ACCESSORY, or when Retained
Accessory Power (RAP) is active. See
Retained Accessory Power (RAP) 0229.
Using the window switch, press to open or
pull to close the window.
The windows may be temporarily disabled if
they are used repeatedly within a
short time.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
34 Keys, Doors, and Windows
Window Lockout
This feature stops the rear passenger
window switches from working.
With Folding Mirrors
Without Folding Mirrors
.Press2to engage the rear window
lockout feature. The indicator light is on
when engaged.
.Press2again to disengage.
Window Express Movement
All windows can be opened without holding
the window switch. Press the switch down
fully and quickly release to express open the
window.
If equipped, pull the window switch up fully
and quickly release to express close the
window. Briefly press or pull the window switch in
the same direction to stop that window’s
express movement.
Window Automatic Reversal System
The express-close feature will reverse
window movement if it comes in contact
with an object. Extreme cold or ice could
cause the window to auto-reverse. The
window will operate normally after the
object or condition is removed.
Automatic Reversal System Override
{Warning
If automatic reversal system override is
active, the window will not reverse
automatically. You or others could be
injured and the window could be
damaged. Before using automatic reversal
system override, make sure that all
people and obstructions are clear of the
window path.
When the engine is on, override the
automatic reversal system by pulling and
holding the window switch if conditions
prevent it from closing.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Seats and Restraints 37
Seats and Restraints
Head Restraints
Head Restraints . . . . . . . . . . . . . . . . . . . . . . . . . 37
Front Seats
Power Seat Adjustment . . . . . . . . . . . . . . . . 40
Lumbar Adjustment . . . . . . . . . . . . . . . . . . . . 40
Reclining Seatbacks . . . . . . . . . . . . . . . . . . . . . 41
Memory Seats . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Heated and Ventilated Front Seats . . . . . 44
Rear Seats
Rear Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Heated Rear Seats . . . . . . . . . . . . . . . . . . . . . . 45
Second Row Seats . . . . . . . . . . . . . . . . . . . . . . 46
Third Row Seats . . . . . . . . . . . . . . . . . . . . . . . . 50
Seat Belts
Seat Belts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
How to Wear Seat Belts Properly . . . . . . 54
Lap-Shoulder Belt . . . . . . . . . . . . . . . . . . . . . . . 56
Seat Belt Use During Pregnancy . . . . . . . . 59
Seat Belt Extender . . . . . . . . . . . . . . . . . . . . . . 59
Safety System Check . . . . . . . . . . . . . . . . . . . 59
Seat Belt Care . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Replacing Seat Belt System Parts after aCrash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Airbag System
Airbag System . . . . . . . . . . . . . . . . . . . . . . . . . 60 Where Are the Airbags? . . . . . . . . . . . . . . . . 62
When Should an Airbag Inflate? . . . . . . . . 63
What Makes an Airbag Inflate? . . . . . . . . 64
How Does an Airbag Restrain? . . . . . . . . . 64
What Will You See after an Airbag
Inflates? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Passenger Sensing System . . . . . . . . . . . . . 66
Servicing the Airbag-Equipped Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Adding Equipment to the Airbag-Equipped Vehicle . . . . . . . . . . . . . . 69
Airbag System Check . . . . . . . . . . . . . . . . . . . 70
Replacing Airbag System Parts after a Crash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Child Restraints
Older Children . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Infants and Young Children . . . . . . . . . . . . . 72
Child Restraint Systems . . . . . . . . . . . . . . . . 74
Where to Put the Restraint . . . . . . . . . . . . . 76
Lower Anchors and Tethers for Children(LATCH System) . . . . . . . . . . . . . . . . . . . . . . . 77
Replacing LATCH System Parts After a Crash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Securing Child Restraints (With the Seat Belt in the Rear Seat) . . . . . . . . . . . . . . . . 84
Securing Child Restraints (With the Seat Belt in the Front Passenger Seat) . . . . . 86
Securing Child Restraints (With the Seat Belt in the Center Front Seat) . . . . . . . . 88
Head Restraints
The vehicle’s front seats have adjustable
head restraints in the outboard seating
positions.
{Warning
With head restraints that are not
installed and adjusted properly, there is a
greater chance that occupants will suffer
a neck/spinal injury in a crash. Do not
drive until the head restraints for all
occupants are installed and adjusted
properly.
If your vehicle has rear head restraints
that fold down, always return them to
the full upright position whenever an
occupant is seated in the seat.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
40 Seats and Restraints
When an occupant or child restraint is in the
seat, always return the head restraint to the
full upright position. Push the head restraint
up and rearward until it locks into place.
Push and pull on the head restraint to make
sure that it is locked.
Front Seats
Power Seat Adjustment
{Warning
You can lose control of the vehicle if you
try to adjust a driver seat while the
vehicle is moving. Adjust the driver seat
only when the vehicle is not moving.
{Warning
The power seats will work with the
ignition off. Children could operate the
power seats and be injured. Never leave
children alone in the vehicle.
To adjust the seat:
.Move the seat forward or rearward by
sliding the control forward or rearward.
.If equipped, raise or lower the front part
of the seat cushion by moving the front
of the control up or down.
.Raise or lower the seat by moving the
rear of the control up or down.
Lumbar Adjustment
.Press and hold the front or rear of the
control to increase or decrease lumbar
support.
.If equipped, press and hold the top or
bottom of the control to raise or lower
lumbar support.