ECU GMC YUKON 2021 Owner's Manual

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Keys, Doors, and Windows 7
Keys, Doors, and
Windows
Keys and Locks
Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Remote Keyless Entry (RKE) System . . . . . 8
Remote Keyless Entry (RKE) SystemOperation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Remote Vehicle Start . . . . . . . . . . . . . . . . . . . 14
Door Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Power Door Locks . . . . . . . . . . . . . . . . . . . . . . . 16
Delayed Locking . . . . . . . . . . . . . . . . . . . . . . . . 17
Automatic Door Locks . . . . . . . . . . . . . . . . . . . 17
Lockout Protection . . . . . . . . . . . . . . . . . . . . . . 17
Safety Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Doors
Liftgate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Power Assist Steps . . . . . . . . . . . . . . . . . . . . . 25
Vehicle Security
Vehicle Security . . . . . . . . . . . . . . . . . . . . . . . . 25
Vehicle Alarm System . . . . . . . . . . . . . . . . . . 25
Steering Column Lock . . . . . . . . . . . . . . . . . . . 27
Immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Immobilizer Operation . . . . . . . . . . . . . . . . . . 27
Exterior Mirrors
Convex Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . 28
Power Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Folding Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . 29
Heated Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . 30
Automatic Dimming Mirror . . . . . . . . . . . . . 30
Reverse Tilt Mirrors . . . . . . . . . . . . . . . . . . . . 30
Interior Mirrors
Interior Rearview Mirrors . . . . . . . . . . . . . . . 30
Manual Rearview Mirror . . . . . . . . . . . . . . . . 30
Automatic Dimming Rearview Mirror . . . 30
Rear Camera Mirror . . . . . . . . . . . . . . . . . . . . 30
Windows
Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Power Windows . . . . . . . . . . . . . . . . . . . . . . . . 33
Sun Visors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Roof
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Keys and Locks
Keys
{Warning
Leaving children in a vehicle with a
remote key is dangerous and children or
others could be seriously injured or killed.
They could operate the power windows
or other controls or make the vehicle
move. The windows will function with
the remote key in the vehicle, and
children or others could be caught in the
path of a closing window. Do not leave
children in a vehicle with a remote key.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
12 Keys, Doors, and Windows
4. Press ENGINE START/STOP. When theremote key is learned, the DIC display
will show that it is ready to program the
next remote key.
5. Remove the remote key from the backup pocket and press
KorQon the
remote key.
To program additional remote keys,
repeat Steps 3–5.
When all additional remote keys are
programmed, press and hold ENGINE
START/STOP for approximately
12 seconds to exit programming mode.
Vehicles without Front Bench Seat 1. Place the two recognized remote keys on the passenger seat.
2. Scroll to the DIC menu to "Remote Key Learn" menu and select.
The DIC displays READY FOR REMOTE #3,
4, 5, ETC.
3. Place the new remote key into thebackup pocket in the left cupholder.
4. Press ENGINE START/STOP. When the remote key is learned, the DIC display
will show that it is ready to program the
next remote key.
5. Remove the remote key from the backup pocket and press
KorQon the
remote key.
To program additional remote keys,
repeat Steps 3–5.
When all additional remote keys are
programmed, press and hold ENGINE
START/STOP for approximately
12 seconds to exit programming mode.
Starting the Vehicle with a Low Remote
Key Battery
For improved vehicle security, the remote
key is equipped with a motion sensor. When
starting the vehicle, if the remote key has
been idle for an extended period of time,
the DIC may display KEY IN SLEEP MODE,
MOVE KEY, THEN START. Move the remote
key slightly and try starting the vehicle.
If the remote key battery is weak or if there
is interference with the signal, the DIC may
display NO KEY FOUND, REPLACE BATTERY IN
KEY or NO REMOTE KEY WAS DETECTED
PLACE KEY IN KEY POCKET THEN START YOUR
VEHICLE when starting the vehicle.
To start the vehicle:

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
16 Keys, Doors, and Windows
.PressQorKon the power door lock
switch.
.Pulling an interior door handle will unlock
the door. Pulling the door handle again
unlatches it.
Keyless Access
The remote key must be within 1 m (3 ft) of
the trunk or door being opened or locked.
Press the button on the door handle to
open. See “Keyless Access Operation” in
Remote Keyless Entry (RKE) System
Operation 08. Free-Turning Locks
The door key lock cylinder turns freely when
either the wrong key is used, or the correct
key is not fully inserted. The free-turning
door lock feature prevents the lock from
being forced open. To reset the lock, turn it
to the vertical position with the correct key
fully inserted. Remove the key and insert it
again. If this does not reset the lock, turn
the key halfway around in the cylinder and
repeat the reset procedure.
Power Door Locks
PressQorKon the Remote Key. See
Remote Keyless Entry (RKE) System
Operation 08.
Q:Press to lock the doors. The indicator
light in the switch will illuminate when
locked.
K: Press to unlock the doors.
Security Status indicator
A light on the upper surface of the driver's
door trim is used to indicate vehicle security
status.
This light will be OFF any time the ignition
is ON, except momentarily when vehicle
doors are locking.
Solid : Indicates securing with doors closed.
Fast Flash : Indicates securing with
doors open.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Keys, Doors, and Windows 17
Slow Flash :Indicates battery conserving
secured state.
No light : Indicates unsecured state.
Delayed Locking
This feature delays the locking of the doors
until five seconds after all doors are closed.
When
Qis pressed on the power door lock
switch while the door is open, a chime will
sound three times indicating delayed locking
is active.
The doors will lock automatically
five seconds after all doors are closed. If a
door is reopened before that time, the
five-second timer will reset when all doors
are closed again.
Press
Qon the door lock switch again or
press
Qon the remote key to lock the
doors immediately.
This feature can be programmed. See
“Delayed Door Lock” underVehicle
Personalization 0126.
Automatic Door Locks
The doors will lock automatically when all
doors are closed, the ignition is on, and the
vehicle is shifted out of P (Park). If a vehicle door is unlocked, and then
opened and closed, the doors will lock either
when your foot is removed from the brake
or the vehicle speed becomes faster than
13 km/h (8 mph).
To unlock the doors:
.PressKon the power door lock switch.
.Shift the transmission into P (Park).
Automatic door locking cannot be disabled.
Automatic door unlocking can be
programmed. See Vehicle Personalization
0 126.
Lockout Protection
When locking is requested with the driver
door open and the vehicle is on or in ACC/
ACCESSORY, all the doors will lock and then
the driver door will unlock.
If the vehicle is off and locking is requested
while a door is open, when all doors are
closed the vehicle will check for remote keys
inside. If a remote key is detected and the
number of remote keys inside has not
reduced, the driver door will unlock and the
horn will sound three times. This can be manually overridden by pressing
and holding
Qon the power door lock
switch.
Safety Locks
The rear door safety locks prevent
passengers from opening the rear doors
from inside the vehicle.
The safety lock is on the inside edge of the
rear doors. To use the safety lock:
1. Move the lever down to the lock position.
2. Close the door.
3. Do the same for the other rear door.

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
26 Keys, Doors, and Windows
key a second time will bypass the
30-second delay and immediately arm
the alarm system.
The vehicle alarm system will not arm if the
doors are locked with the mechanical key.
If the driver door is opened without first
unlocking with the remote key, the horn will
chirp and the lights will flash to indicate
pre-alarm. If the vehicle is not started,
or the door is not unlocked by pressing
K
on the remote key during the 10-second
pre-alarm, the alarm will be activated.
The alarm will also be activated if a
passenger door, the liftgate, or the hood is
opened without first disarming the system.
When the alarm is activated, the turn
signals flash and the horn sounds for about
30 seconds. The alarm system will then
re-arm to monitor for the next unauthorized
event.
Disarming the Alarm System
To disarm the alarm system or turn off the
alarm if it has been activated:
.PressKon the remote key.
.Unlock the vehicle using the Keyless
Access system.
.Start the vehicle. To avoid setting off the alarm by accident:
.Lock the vehicle after all occupants have
exited.
.Always unlock a door with the remote
key, or use the Keyless Access system.
Unlocking the driver door with the
mechanical key will not disarm the
system or turn off the alarm.
How to Detect a Tamper Condition
IfKis pressed on the remote key and the
horn chirps three times, an alarm occurred
previously while the alarm system was
armed.
If the alarm has been activated, a message
will appear on the DIC.
Power Sounder, Inclination Sensor, and
Intrusion Sensor
In addition to the standard theft-deterrent
system features, this system may also have
a power sounder, inclination sensor, and
intrusion sensor.
The power sounder provides an audible
alarm which is distinct from the vehicle’s
horn. It has its own power source, and can
sound an alarm if the vehicle’s battery is
compromised. The inclination sensor can set off the alarm
if it senses movement of the vehicle, such
as a change in vehicle orientation.
The intrusion sensor monitors the vehicle
interior, and can activate the alarm if it
senses unauthorized entry into the vehicle’s
interior. Do not allow passengers or pets to
remain in the vehicle when the intrusion
sensor is activated.
Before arming the theft-deterrent system
and activating the intrusion sensor:
.Make sure all doors and windows are
completely closed.
.Secure any loose items such as a
sunshades.
.Make sure there are no obstructions
blocking the sensors in the front overhead
console.
.Close DVD screens before leaving the
vehicle.

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
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
52 Seats and Restraints
1. Ensure the seat belt is in the beltstowage clip.
2. Open the liftgate to access the controls for the seat.
3. Press and hold the switch (2) on the side trim of the cargo area to raise the third
row seatback.
The left switch raises the left seatback,
and the right switch raises the right
seatback.
{Warning
A seat belt that is improperly routed, not
properly attached, or twisted will not
provide the protection needed in a crash.
(Continued)
Warning (Continued)
The person wearing the belt could be
seriously injured. After raising the rear
seatback, always check to be sure that
the seat belts are properly routed and
attached, and are not twisted.
4. Reconnect the center seat belt mini-latch to the mini-buckle. Do not let it twist.
5. Pull on the seat belt to be sure the mini-latch is secure.
6. Repeat the steps for the other seatback, if desired.
Manual Seatback Folding (If Equipped)
1. Pull up on the lever to release theseatback.
2. Push the seatback forward to lay flat.
3. Repeat for the other seatback, if necessary.
Returning the Third Row Seatback to the
Upright Position
1. Ensure the seat belt is in the belt stowage clip.
2. From the rear of the vehicle, raise the seatback to the upright position using
the pull strap on the back of the third
row seat, or lift the seatback and push it
into place from inside the vehicle.