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GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 239
If the parking brake and/or brake pedal
is not applied within 20 seconds, the
transfer case will remain in the original
state.
6. If the transmission is not shifted into N (Neutral) or the vehicle has not slowed
to 5 km/h (3 mph) within 20 seconds,
the transfer case will remain in its
original state. This will be indicated in
the instrument cluster.
Shifting Out of N (Neutral)
To shift out of N (Neutral): 1. Turn the ignition on with the engine off. See Ignition Positions 0226.
2. Set the parking brake. See Electric
Parking Brake 0240.
3. Shift the transmission to N (Neutral).
4. Shift the transfer case to 2
m. Transfer
case shifts out of N (Neutral) can only be
made into 2
m. When the shift to 2mis
complete, the graphic in the instrument
cluster will stop flashing. If the transfer
case cannot complete a shift, the graphic
will return to the previously selected
setting. Single Speed Transfer Case
If equipped, the transfer case controls are
used to shift into and out of four-wheel
drive.
To shift the transfer case, press the desired
button. The graphic in the instrument
cluster will flash while a shift is in progress.
The graphic displayed will change to indicate
the setting requested.
When the shift is complete the graphic will
stop flashing. The DIC message turns off
once the shift is complete. If the transfer
case cannot complete a shift request, it will
go back to its last chosen setting.
The settings are: 2
m(Two-Wheel Drive High) :
Use for driving
on most streets and highways. The front
axle is not engaged. This setting provides
the best fuel economy.
4
m(Four-Wheel Drive High) : Use this
setting when extra traction is needed, such
as when driving on snowy or icy roads,
when off-roading, or when plowing snow.
AUTO (Automatic Four-Wheel Drive)
Use when road surface conditions are
variable. When driving in AUTO, the front
axle is engaged, and the vehicle's power is
sent to the front and rear wheels
automatically based on driving conditions.
This setting provides slightly lower fuel
economy than 2
m.
Shifts between 2
m, 4m, and AUTO
Any of these shifts can be made at normal
driving speed.
The actual 4x4 shift request is only made
after the button is released. The 4x4 graphic
will remain flashing until the shift request
has completed. A DIC message displays.
Once the 4x4 shift has completed, the DIC
message disappears, the 4x4 graphic stops
flashing, and the current setting is indicated.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
240 Driving and Operating
The actual 4x4 shift request is only made
after the button is released. The 4x4 graphic
will remain flashing until the shift request
has completed.
A DIC message displays. Once the 4x4 shift
has completed, the DIC message disappears,
the 4x4 graphic stops flashing, and the
current setting is indicated.
Brakes
Electric Brake Boost
Vehicles equipped with electric brake boost
have hydraulic brake circuits that are
electronically controlled when the brake
pedal is applied during normal operation.
The system performs routine tests and turns
off within a few minutes after the vehicle is
turned off. Noise may be heard during this
time. If the brake pedal is pressed during
the tests or when the electric brake boost
system is off, a noticeable change in pedal
force and travel may be felt. This is normal.
Antilock Brake System (ABS)
The Antilock Brake System (ABS) helps
prevent a braking skid and maintain steering
while braking hard.
If there is a problem with ABS, this warning
light stays on. SeeAntilock Brake System
(ABS) Warning Light 0113.
ABS does not change the time needed to
get a foot on the brake pedal and does not
always decrease stopping distance. If you
get too close to the vehicle ahead, there will
not be enough time to apply the brakes if
that vehicle suddenly slows or stops. Always
leave enough room ahead to stop, even
with ABS.
Using ABS
Do not pump the brakes. Just hold the brake
pedal down firmly. Hearing and feeling ABS
operate is normal.
Braking in Emergencies
ABS allows steering and braking at the same
time. In many emergencies, steering can
help even more than braking.
Electric Parking Brake
The Electric Parking Brake (EPB) can always
be applied, even if the vehicle is off. In case
of insufficient electrical power, the EPB
cannot be applied or released. To prevent
draining the battery, avoid unnecessary
repeated cycles of the EPB.
The system has a red parking brake status
light and an amber service parking brake
warning light. See Electric Parking Brake
Light 0113 and
Service Electric Parking Brake Light 0113.
There are also parking brake-related Driver
Information Center (DIC) messages.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 241
Before leaving the vehicle, check the red
parking brake status light to ensure that the
parking brake is applied.
EPB Apply
To apply the EPB:1. Be sure the vehicle is at a complete stop.
2. Press the EPB switch momentarily.
The red parking brake status light will flash
and then stay on once the EPB is fully
applied. If the red parking brake status light
flashes continuously, then the EPB is only
partially applied or there is a problem with
the EPB. A DIC message will display. Release
the EPB and try to apply it again. If the
light does not come on, or keeps flashing,
have the vehicle serviced. Do not drive the
vehicle if the red parking brake status light
is flashing. See your dealer.
If the amber service parking brake warning
light is on, press the EPB switch. Continue to
hold the switch until the red parking brake
status light remains on. If the amber service
parking brake warning light is on, see your
dealer. If the EPB is applied while the vehicle is
moving, the vehicle will decelerate as long
as the switch is pressed. If the switch is
pressed until the vehicle comes to a stop,
the EPB will remain applied.
The vehicle may automatically apply the EPB
in some situations when the vehicle is not
moving. This is normal, and is done to
periodically check the correct operation of
the EPB system, or at the request of other
safety functions that utilize the EPB.
If the EPB fails to apply, block the rear
wheels to prevent vehicle movement.
EPB Release
To release the EPB:
1. Turn the ignition on or to ACC/ ACCESSORY.
2. Apply and hold the brake pedal.
3. Press the EPB switch momentarily.
The EPB is released when the red parking
brake status light is off.
If the amber service parking brake warning
light is on, release the EPB by pressing and
holding the EPB switch. Continue to hold the
switch until the red parking brake status
light is off. If either light stays on after
release is attempted, see your dealer.
Caution
Driving with the parking brake on can
overheat the brake system and cause
premature wear or damage to brake
system parts. Make sure that the parking
brake is fully released and the brake
warning light is off before driving.
If you are towing a trailer and parking on a
hill, see Driving Characteristics and Towing
Tips 0280.
Automatic EPB Release
The EPB will automatically release if the
vehicle is running, placed into gear, and an
attempt is made to drive away. Avoid rapid
acceleration when the EPB is applied, to
preserve parking brake lining life.
Brake Assist
Brake Assist detects rapid brake pedal
applications due to emergency braking
situations and provides additional braking to
activate the Antilock Brake System (ABS) if
the brake pedal is not pushed hard enough
to activate ABS normally. Minor noise, brake
pedal pulsation, and/or pedal movement
during this time may occur. Continue to

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 243
comes on, and the appropriate message will
appear on the Driver Information
Center (DIC).
The indicator light for both systems is in the
instrument cluster. This light will:
.Flash when TCS is limiting wheel spin.
.Flash when StabiliTrak/ESC is activated.
.Turn on and stay on when either system
is not working. SeeTraction Control
System (TCS)/Electronic Stability Control
Light 0115.
If either system fails to turn on or to
activate, a message displays in the DIC, and
dcomes on and stays on to indicate that
the system is inactive and is not assisting
the driver in maintaining control. Without
the assistance of properly functioning
StabiliTrak/ESC the possibility of rollover is
increased. Adjust driving accordingly.
If
dcomes on and stays on:
1. Stop the vehicle. 2. Turn the engine off and wait 15 seconds.
3. Start the engine.
Drive the vehicle. If
dcomes on and stays
on, see your dealer.
Turning the Systems Off and On
The button for TCS and StabiliTrak/ESC is on
the instrument panel to the left of the
steering wheel.
Caution
Do not repeatedly brake or accelerate
heavily when TCS is off. The vehicle
driveline could be damaged. To turn off only TCS, press and release
g.
The traction off light
idisplays in the
instrument cluster. The appropriate message
will display in the DIC. To turn TCS on again,
press and release
g. The traction off light
idisplayed in the instrument cluster will
turn off.
If TCS is limiting wheel spin when
gis
pressed, the system will not turn off until
the wheels stop spinning.
To turn off both TCS and StabiliTrak/ESC,
press and hold
guntil the traction off light
iand the StabiliTrak OFF lightgcome on
and stay on in the instrument cluster, then
release. The appropriate message will
display in the DIC.
To turn TCS and StabiliTrak/ESC on again,
press and release
g. The traction off light
iand the StabiliTrak OFF lightgin the
instrument cluster turn off.
For vehicles without four corner air
suspension StabiliTrak/ESC will automatically
turn on if the vehicle exceeds 56 km/h
(35 mph). Traction control will remain off.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
244 Driving and Operating
For vehicles with four corner air suspension
StabiliTrak/ESC will automatically turn on if
the vehicle exceeds 32 km/h (20 mph).
The vehicle has a Trailer Sway Control (TSC)
feature and a Hill Start Assist (HSA) feature.
SeeTrailer Sway Control (TSC) 0295 or
Hill Start Assist (HSA) 0242.
Adding accessories can affect the vehicle
performance. See Accessories and
Modifications 0309.
Hill Descent Control (HDC)
If equipped, Hill Descent Control (HDC) sets
and maintains vehicle speed while driving
down steep grades in a forward or reverse
gear. The HDC switch is on the instrument
panel to the left of the steering wheel.Press5to enable or disable HDC. Vehicle
speed must be below 60 km/h (37 mph).
When enabled, the HDC light displays on
the instrument cluster.
A blinking HDC light indicates the system is
actively applying the brakes to maintain
vehicle speed. HDC can maintain vehicle
speeds between 1 and 30 km/h (1 and
19 mph) on grades greater than or equal
to 5%. If HDC is to be used for more than
three minutes or on grades steeper than
25%, the transfer case should be put into
Four-Wheel Drive Low (4
n) to reduce the
possibility of brake overheating.
Noise from the hydraulic brake control
module is normal when HDC is active.
When HDC is activated, the initial HDC
speed is set to the current driving speed.
It can be increased or decreased by pressing
+RES or SET- on the steering wheel, or by
applying the accelerator or brake pedal. This
adjusted speed becomes the new set speed.
HDC will remain enabled between 30 and
60 km/h (19 and 37 mph); however, vehicle
speed cannot be set or maintained in this
range. HDC will automatically disable if the
vehicle speed is above 80 km/h (50 mph) or
above 60 km/h (37 mph) for at least
30 seconds.
5must be pressed again to re-enable HDC.
HDC may disable after an extended period
of use. If this happens, HDC will require
time to cool down. The length of time HDC
remains active depends on road conditions,
grade, set speed, vehicle loading, and
outside temperature.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
246 Driving and Operating
6Snow/Ice Mode :Snow/Ice improves
vehicle acceleration on snow and ice covered
roads. When active, Snow/Ice Mode will
adjust acceleration to optimize traction on
slippery surfaces. This can compromise the
acceleration on dry asphalt. This feature is
not intended for use when the vehicle is
stuck in sand, mud, ice, snow, or gravel.
If the vehicle becomes stuck see If the
Vehicle Is Stuck 0221.
7Off-Road Mode : Use this mode for
off-road recreational driving. Off-Road Mode
should be used to improve driving at
moderate speeds, on grass, gravel, dirt,
unpaved roads, or snow-covered roads. The
accelerator pedal is tuned for off-road use.
This mode modifies pedal mapping, AWD,
steering, ride height, ABS, ESC, and TCS
performance. For more information on
off-road driving, see Off-Road Driving0216.
_Tow/Haul Mode : For more
information on Tow/Haul Mode, see Tow/
Haul Mode 0235.
If equipped, select Terrain Mode by pressing
the
gbelow the 4mtransfer case
button.
gTerrain Mode : Use this mode when
traveling on very rough roads at very low
speeds, such as a two-track or heavily rutted
road. This can also be used for pulling a
boat out of the water on a trailer. When in
Terrain Mode, the vehicle will shift
automatically but will hold a lower gear
longer to maximize engine torque. This
mode has a unique pedal map and
transmission shift pattern for better control
at lower speeds and over rough terrain. This
mode modifies accelerator pedal mapping, transmission shift pattern, ride height,
suspension, steering, AWD, eSLD, ESC
performance and TCS performance.
When the vehicle comes to a stop on an
upward grade, Automatic Vehicle Hold is
engaged until the driver presses the
accelerator pedal. Stop/Start and cruise
control are disabled in Terrain Mode.
Active Braking during lift throttle will be
engaged. This feature automatically applies
light braking to simulate heavy engine
braking of four-wheel-dive low. It also
applies light braking in D (Drive) until the
vehicle is at idle speeds. In M1 and M2 light
braking will typically bring the vehicle to a
stop. Active Braking during lift throttle will
also reduce trailer braking.
Terrain Mode will automatically exit to
Normal Mode if the brake temperatures
become too hot, electronic parking brake
becomes inoperable or the vehicle cannot
perform braking or vehicle hold.
For more information on off-road driving,
see
Off-Road Driving 0216 and
Hill and Mountain Roads 0220.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 247
Terrain Mode DriveSelect Expected Vehicle Behavior Ideal Terrain
Drive (L3-Lx) Minor deceleration when off
throttle and mild ability to
modulate throttle; mimics
performance of 4
nwithout torque
multiplication. Grassy fields,
mild two tracks,
rutted roads,
large rolling hills,
L2 Moderate deceleration when off
throttle and moderate ability to
modulate throttle; will bring vehicle
to a stop in most cases. Mild rock crawling,
heavy ruts,
short, steeper grades,
L1 Significant deceleration when off
throttle and significant ability to
modulate throttle; will bring vehicle
to a stop in most cases. Rock crawling downhill
Vehicle Hold Features:
.When the vehicle comes to a stop on an
incline grade in forward gear or on a
decline grade in reverse gear, Vehicle
Hold is engaged until the accelerator
pedal is pressed.
.When the vehicle is in forward gear on a
decline, the vehicle is allowed to creep
down the hill when the brake pedal is released without pressing the accelerator
pedal. The vehicle will also creep forward
on flat ground.
.If the driver seat belt is removed and the
driver door is opened while the vehicle is
being held, EPB will be engaged.
.EPB will engage if the vehicle is held for
an extended period.Terrain Mode is only available on vehicles
equipped with the single speed
transfer case.
Terrain Mode can only be active when:
.Vehicle speed is less than 80 km/h
(50 mph).
.The transfer case is in 4m.
Frequent use of this mode may cause brake
wear due to the light braking.
The vehicle will automatically exit the mode
if the brakes get too hot. Terrain Mode can
be turned back on after the brakes have
cooled.
When Terrain Mode is selected:
.Auto Engine Start/Stop will be disabled.
.The Terrain Mode indicator displays on
the instrument cluster.
Magnetic Ride Control
This vehicle may have a semi-active damping
system called Magnetic Ride Control. With
this feature, improved vehicle ride and
handling is provided under a variety of
passenger and loading conditions.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
250 Driving and Operating
Aerodynamic Height is 20 mm (0.75 in)
lower than Normal Height. This ride height
lowers the vehicle at higher vehicle speeds
to improve aerodynamics.
The vehicle will lower to Aerodynamic
Height when vehicle speed exceeds
105 km/h (65 mph) for a period of time. The
vehicle will raise to Normal Height when the
vehicle slows to less than 48 km/h
(30 mph).
Aerodynamic Height is automatically
disabled when a trailer is connected to the
vehicle or Tow/Haul Driver Mode is active.
Suspension Modes
The air suspension has two special modes
located in the infotainment screen under
Settings/Vehicle/Suspension. When either is
active, the following amber icon will be
illuminated in the instrument cluster.
SeeFour Corner Air Suspension Light 0117. Service Mode
Service Mode will disable all air suspension
operation including raising and lowering the
vehicle and operation of the air compressor.
This mode is useful when the vehicle is
being towed on a flat bed or when any
work under the vehicle is being performed.
Service Mode is automatically enabled when
the vehicle is put on a hoist or a floor jack
is used to raise a corner. Service Mode may
temporarily enable during intense off-road
situations to prevent damaging air
suspension activity. Service Mode
automatically disables when vehicle speed
exceeds 16 km/h (10 mph).
Alignment Mode
Alignment Mode will optimize the vehicle
height to provide the most accurate wheel
alignment. This mode should be enabled
once the vehicle is driven onto the
alignment station.
To enable Alignment Mode, ensure the
vehicle is at Normal Height and shift the
vehicle to Neutral. Alignment Mode
automatically disables when vehicle speed
exceeds 16 km/h (10 mph).
Air Suspension Operation with Door(s) or
Hood Open
The air suspension will temporarily suspend
all height changes while the hood or any
door is open.
System Over-Temperature
If the air suspension is under heavy use, the
system may temporarily suspend all height
changes to allow compressor cooldown.
When this occurs and a height change is
requested, a
‘Leveling System Unavailable’
message will be displayed in the instrument
cluster.
Suspension Lowered for Stability
In the event of a loss of Electronic Stability
Control, the air suspension will lower the
vehicle at higher speeds to provide increased
stability. This will be accompanied by a
‘Vehicle Lowering for Stability’ message in
the instrument cluster.
Excessive Vehicle Loading
If the air suspension detects excessive
vehicle loading, it will not raise above
Normal Height.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
252 Driving and Operating
Resuming a Set Speed
If the cruise control is set at a desired speed
and then the brakes are applied or
*is
pressed, the cruise control is disengaged
without erasing the set speed from memory.
Once the vehicle reaches about 40 km/h
(25 mph) or more, press RES+ up briefly. The
vehicle returns to the previously set speed.
Increasing Speed While Using Cruise Control
Do one of the following:
.Press and hold +RES up until the desired
speed is reached, then release it.
.To increase vehicle speed in small
increments, press +RES up briefly. For
each press, the vehicle goes about 1 km/h
(1 mph) faster.
The speedometer reading can be displayed
in either English or metric units. See
Instrument Cluster 0104. The increment
value used depends on the units displayed.
Reducing Speed While Using Cruise Control
Do one of the following:
.Press and hold SET– down until the
desired lower speed is reached, then
release it.
.To slow down in small increments, press
SET– down briefly. For each press, the
vehicle goes about 1 km/h (1 mph) slower.
The speedometer reading can be displayed
in either English or metric units. See
Instrument Cluster 0104. The increment
value used depends on the units displayed.
Passing Another Vehicle While Using Cruise
Control
Use the accelerator pedal to increase the
vehicle speed. When you take your foot off
the pedal, the vehicle will slow down to the
previously set cruise speed. While pressing
the accelerator pedal or shortly following
the release to override cruise control, briefly
pressing SET– will result in cruise control set
to the current vehicle speed.
Using Cruise Control on Hills
How well the cruise control works on hills
depends on the vehicle speed, the load, and
the steepness of the hills. When going up
steep hills, pressing the accelerator pedal
may be necessary to maintain vehicle speed.
While going downhill, cruise braking helps
maintain driver selected speed. Cruise Grade Braking is enabled when the
vehicle is started and cruise control is active.
It is not enabled in Range Selection Mode.
It assists in maintaining driver selected
speed when driving on downhill grades by
using the engine and transmission to slow
the vehicle.
For other forms of descent control, see
Hill
Descent Control (HDC) 0244, Automatic
Transmission 0232, and Tow/Haul Mode
0 235.
Ending Cruise Control
There are four ways to end cruise control:
.Step lightly on the brake pedal.
.Press*.
.Shift the transmission to N (Neutral).
.To turn off cruise control, press5.
Erasing Speed Memory
The cruise control set speed is erased from
memory if
5is pressed or the ignition is
turned off.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
258 Driving and Operating
Irregular Objects Affecting ACC
ACC may have difficulty detecting the
following objects:
.Vehicles with cargo extending from the
back end.
.Non-standard shaped vehicles, such as
vehicle transport, vehicles with a side car
fitted, or horse carriages.
.Objects that are close to the front of your
vehicle.
ACC Automatically Disengages
ACC may automatically disengage and the
driver will need to manually apply the
brakes to slow the vehicle if:
.The sensors are blocked.
.The Traction Control System (TCS) or
StabiliTrak/ESC system has activated or
been disabled.
.There is a fault in the system.
.The radar falsely reports blockage when
driving in a desert or remote area with
no other vehicles or roadside objects.
A DIC message may display to indicate
that ACC is temporarily unavailable.
The ACC indicator will turn white when ACC
is no longer active. In some cases, when ACC is temporarily
unavailable, regular cruise control may be
used. See
“Switching Between ACC and
Regular Cruise Control” previously in this
section. Always consider driving conditions
before using either cruise control system.
Notification to Resume ACC
ACC will maintain a follow gap behind a
detected vehicle and slow your vehicle to a
stop behind that vehicle.
If the stopped vehicle ahead has driven
away and ACC has not resumed, the vehicle
ahead indicator will flash as a reminder to
check traffic ahead before proceeding. In
addition, the left and right sides of the
Safety Alert Seat will pulse three times,
or three beeps will sound. See ”Alert Type”
and “Adaptive Cruise Go Notifier” in
“Collision/Detection Systems” underVehicle
Personalization 0126.
When the vehicle ahead drives away, press
RES+ or the accelerator pedal to resume
ACC. If stopped for more than two minutes
or if the driver door is opened and the
driver seat belt is unbuckled, the ACC
automatically applies the Electric Parking
Brake (EPB) to hold the vehicle. The EPB
status light will turn on. See Electric Parking
Brake 0240. A DIC warning message may display
indicating to shift to P (Park) before exiting
the vehicle. See
Vehicle Messages 0125.
{Warning
If ACC has stopped the vehicle, and if ACC
is disengaged, turned off, or canceled, the
vehicle will no longer be held at a stop.
The vehicle can move. When ACC is
holding the vehicle at a stop, always be
prepared to manually apply the brakes.
{Warning
Leaving the vehicle without placing it in
P (Park) can be dangerous. Do not leave
the vehicle while it is being held at a
stop by ACC. Always place the vehicle in
P (Park) and turn off the ignition before
leaving the vehicle.
ACC Override
If using the accelerator pedal while ACC is
active, the ACC indicator turns blue on the
instrument cluster indicating ACC braking
will not occur. ACC will resume operation
when the accelerator pedal is not being
pressed.