wheel GMC YUKON 2021 Workshop Manual

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 217
Loading the Vehicle for Off-Road Driving
{Warning
.Unsecured cargo on the load floor can
be tossed about when driving over
rough terrain. You or your passengers
can be struck by flying objects. Secure
the cargo properly.
.Keep cargo in the cargo area as far
forward and as low as possible. The
heaviest things should be on the floor,
forward of the rear axle.
.Heavy loads on the roof raise the
vehicle's center of gravity, making it
more likely to roll over. You can be
seriously or fatally injured if the
vehicle rolls over. Put heavy loads
inside the cargo area, not on the roof.
For more information about loading the
vehicle, see Vehicle Load Limits 0222 and
Tires 0339.
Environmental Concerns
.Always use established trails, roads, and
areas that have been set aside for public
off-road recreational driving and obey all
posted regulations.
.Do not damage shrubs, flowers, trees,
or grasses or disturb wildlife.
.Do not park over things that burn. See
Parking over Things That Burn 0231.
Driving on Hills
Driving safely on hills requires good
judgment and an understanding of what the
vehicle can and cannot do.
{Warning
Many hills are simply too steep for any
vehicle. Driving up hills can cause the
vehicle to stall. Driving down hills can
cause loss of control. Driving across hills
can cause a rollover. You could be injured
or killed. Do not drive on steep hills.
Before driving on a hill, assess the
steepness, traction, and obstructions. If the
terrain ahead cannot be seen, get out of the
vehicle and walk the hill before driving
further.
When driving on hills:
.Use a low gear and keep a firm grip on
the steering wheel.
.Maintain a slow speed.
.When possible, drive straight up or down
the hill.
.Slow down when approaching the top of
the hill.
.Use headlamps even during the day to
make the vehicle more visible.
{Warning
Driving to the top of a hill at high speed
can cause a crash. There could be a
drop-off, embankment, cliff, or even
another vehicle. You could be seriously
injured or killed. As you near the top of a
hill, slow down and stay alert.
.Never go downhill forward or backward
with either the transmission or transfer
case in N (Neutral). The brakes could
overheat and you could lose control.
{Warning
If the vehicle has the two-speed
automatic or electronic transfer case,
shifting the transfer case to N (Neutral)
can cause your vehicle to roll even if the
transmission is in P (Park). This is because
the N (Neutral) position on the transfer (Continued)

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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218 Driving and Operating
Warning (Continued)
case overrides the transmission. You or
someone else could be injured. If leaving
the vehicle, set the parking brake and
shift the transmission to P (Park). Shift
the transfer case to any position but
N (Neutral).
.When driving down a hill, keep the
vehicle headed straight down. Use a low
gear because the engine will work with
the brakes to slow the vehicle and help
keep the vehicle under control.
{Warning
Heavy braking when going down a hill
can cause your brakes to overheat and
fade. This could cause loss of control and
you or others could be injured or killed.
Apply the brakes lightly when descending
a hill and use a low gear to keep vehicle
speed under control.
If the vehicle stalls on a hill: 1. Apply the brakes to stop the vehicle, and then apply the parking brake. 2. Shift into P (Park) and then restart the
engine.
.If driving uphill when the vehicle
stalls, shift to R (Reverse), release the
parking brake, and back
straight down.
.Never try to turn the vehicle around.
If the hill is steep enough to stall the
vehicle, it is steep enough to cause it
to roll over.
.If you cannot make it up the hill,
back straight down the hill.
.Never back down a hill in N (Neutral)
using only the brake. The vehicle can
roll backward quickly and you could
lose control.
.If driving downhill when the vehicle
stalls, shift to a lower gear, release
the parking brake, and drive straight
down the hill.
3. If the vehicle cannot be restarted after stalling, set the parking brake, shift into
P (Park), and turn the vehicle off.
3.1. Leave the vehicle and seek help.
3.2. Stay clear of the path the vehicle would take if it rolled downhill.
.Avoid turns that take the vehicle across
the incline of the hill. A hill that can be
driven straight up or down might be too
steep to drive across. Driving across an
incline puts more weight on the downhill
wheels, which could cause a downhill
slide or a rollover.
.Surface conditions can be a problem.
Loose gravel, muddy spots, or even wet
grass can cause the tires to slip sideways,
downhill. If the vehicle slips sideways, it
can hit something that will trip it —a
rock, a rut, etc. —and roll over.
.Hidden obstacles can make the steepness
of the incline more severe. If a rock is
driven across with the uphill wheels, or if
the downhill wheels drop into a rut or
depression, the vehicle can tilt even more.
.If an incline must be driven across, and
the vehicle starts to slide, turn downhill.
This should help straighten out the
vehicle and prevent the side slipping.
{Warning
Getting out of the vehicle on the
downhill side when stopped across an
incline is dangerous. If the vehicle rolls
over, you could be crushed or killed.
(Continued)

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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Driving and Operating 219
Warning (Continued)
Always get out on the uphill side of the
vehicle and stay well clear of the
rollover path.
Driving in Mud, Sand, Snow, or Ice
Use a low gear when driving in mud—the
deeper the mud, the lower the gear. Keep
the vehicle moving to avoid getting stuck.
Traction changes when driving on sand. On
loose sand, such as on beaches or sand
dunes, the tires tend to sink into the sand.
This affects steering, accelerating, and
braking. Drive at a reduced speed and avoid
sharp turns or abrupt maneuvers.
Traction is reduced on hard packed snow
and ice and it is easy to lose control. Reduce
vehicle speed when driving on hard packed
snow and ice.
{Warning
Driving on frozen lakes, ponds, or rivers
can be dangerous. Ice conditions vary
greatly and the vehicle could fall through
(Continued)
Warning (Continued)
the ice; you and your passengers could
drown. Drive your vehicle on safe
surfaces only.
Driving in Water
{Warning
Driving through rushing water can be
dangerous. Deep water can sweep your
vehicle downstream and you and your
passengers could drown. If it is only
shallow water, it can still wash away the
ground from under your tires. Traction
could be lost, and the vehicle could roll
over. Do not drive through rushing water.
Caution
Do not drive through standing water if it
is deep enough to cover the wheel hubs,
axles, or exhaust pipe. Deep water can
damage the axle and other vehicle parts.
If the standing water is not too deep, drive
through it slowly. At faster speeds, water
can get into the engine and cause it to stall.
Stalling can occur if the exhaust pipe is under water. Do not turn off the ignition
when driving through water. If the exhaust
pipe is under water, the engine will not
start. When going through water, the brakes
get wet and it may take longer to stop. See
“Driving on Wet Roads”
later in this section.
After Off-Road Driving
Remove any brush or debris that has
collected on the underbody or chassis,
or under the hood. These accumulations can
be a fire hazard.
After operation in mud or sand, have the
brake linings cleaned and checked. These
substances can cause glazing and uneven
braking. Check the body structure, driveline,
steering, suspension, wheels, tires, and
exhaust system for damage and check the
fuel lines and cooling system for any
leakage.
More frequent maintenance service is
required. See theMaintenance Schedule
0 384.
Driving on Wet Roads
Rain and wet roads can reduce vehicle
traction and affect your ability to stop and
accelerate. Always drive slower in these

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 221
Winter Driving
Driving on Snow or Ice
Snow or ice between the tires and the road
creates less traction or grip, so drive
carefully. Wet ice can occur at about 0 °C
(32 °F) when freezing rain begins to fall.
Avoid driving on wet ice or in freezing rain
until roads can be treated.
For Slippery Road Driving:
.Accelerate gently. Accelerating too quickly
causes the wheels to spin and makes the
surface under the tires slick.
.Turn on Traction Control. SeeTraction
Control/Electronic Stability Control 0242.
.The Antilock Brake System (ABS) improves
vehicle stability during hard stops, but
the brakes should be applied sooner than
when on dry pavement. See Antilock
Brake System (ABS) 0240.
.Allow greater following distance and
watch for slippery spots. Icy patches can
occur on otherwise clear roads in shaded
areas. The surface of a curve or an
overpass can remain icy when the
surrounding roads are clear. Avoid sudden
steering maneuvers and braking while
on ice.
.Turn off cruise control.
Blizzard Conditions
Stop the vehicle in a safe place and signal
for help. Stay with the vehicle unless there
is help nearby. If possible, use Roadside
Assistance. See Roadside Assistance Program
0 402. To get help and keep everyone in
the vehicle safe:
.Turn on the hazard warning flashers.
.Tie a red cloth to an outside mirror.
{Warning
Snow can trap engine exhaust under the
vehicle. This may cause exhaust gases to
get inside. Engine exhaust contains
carbon monoxide (CO), which cannot be
seen or smelled. It can cause
unconsciousness and even death.
If the vehicle is stuck in snow:
.Clear snow from the base of the
vehicle, especially any blocking the
exhaust pipe.
.Open a window about 5 cm (2 in) on
the vehicle side that is away from the
wind, to bring in fresh air.
(Continued)
Warning (Continued)
.Fully open the air outlets on or under
the instrument panel.
.Adjust the climate control system to
circulate the air inside the vehicle and
set the fan speed to the highest
setting. See“Climate Control Systems.”
For more information about CO, see
Engine Exhaust 0231.
To save fuel, run the engine for short
periods to warm the vehicle and then shut
the engine off and partially close the
window. Moving about to keep warm also
helps.
If it takes time for help to arrive, when
running the engine, push the accelerator
pedal slightly so the engine runs faster than
the idle speed. This keeps the battery
charged to restart the vehicle and to signal
for help with the headlamps. Do this as
little as possible, to save fuel.
If the Vehicle Is Stuck
Slowly and cautiously spin the wheels to
free the vehicle when stuck in sand, mud,
ice, or snow.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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222 Driving and Operating
If stuck too severely for the traction system
to free the vehicle, turn the traction system
off and use the rocking method. See
Traction Control/Electronic Stability Control
0242.
{Warning
If the vehicle's tires spin at high speed,
they can explode, and you or others
could be injured. The vehicle can
overheat, causing an engine compartment
fire or other damage. Spin the wheels as
little as possible and avoid going above
56 km/h (35 mph).
Rocking the Vehicle to Get it Out
Turn the steering wheel left and right to
clear the area around the front wheels. Turn
off any traction system. Shift back and forth
between R (Reverse) and a low forward gear,
spinning the wheels as little as possible. To
prevent transmission wear, wait until the
wheels stop spinning before shifting gears.
Release the accelerator pedal while shifting,
and press lightly on the accelerator pedal
when the transmission is in gear. Slowly
spinning the wheels in the forward and
reverse directions causes a rocking motion
that could free the vehicle. If that does not get the vehicle out after a few tries, it
might need to be towed out. If the vehicle
does need to be towed out, see
Towing the
Vehicle 0370.
Recovery Hooks
{Warning
Never pull on recovery hooks from the
side. The hooks could break and you and
others could be injured. When using
recovery hooks, always pull the vehicle
from the front.
Caution
Never use recovery hooks to tow the
vehicle. The vehicle could be damaged,
and the repairs would not be covered by
the vehicle warranty.
There are recovery hooks at the front of the
vehicle. Use them if the vehicle is stuck
off-road and needs to be pulled some place
to continue driving.
Vehicle Load Limits
It is very important to know how much
weight the vehicle can carry. This
weight is called the vehicle capacity
weight and includes the weight of all
occupants, cargo, and all
nonfactory-installed options. Two labels
on the vehicle may show how much
weight it was designed to carry, the
Tire and Loading Information label and
the Certification/Tire label.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 227
interference to the Keyless Access system.
SeeRemote Keyless Entry (RKE) System
Operation 08.
To shift out of P (Park), the ignition must be
on or in Service Mode, and the brake pedal
must be applied.
{Warning
Turning off the vehicle while moving may
cause loss of power assist in the brake
and steering systems and disable the
airbags. While driving, only shut the
vehicle off in an emergency.
Stopping the Engine/LOCK/OFF (No Indicator
Lights) : When the vehicle is stopped, press
ENGINE START/STOP once to turn the
engine off.
If the vehicle is in P (Park), the ignition will
turn off, and Retained Accessory Power (RAP)
will remain active. See Retained Accessory
Power (RAP) 0229.
If the vehicle is not in P (Park), the ignition
will return to ACC/ACCESSORY and display
the message SHIFT TO PARK in the Driver
Information Center (DIC). When the vehicle is
shifted into P (Park), the ignition system will
turn off. The vehicle may have an electric steering
column lock. The lock is activated when the
ignition is turned off and either front door is
opened. A sound may be heard as the lock
actuates or releases. The steering column
lock may not release with the wheels turned
off center. If this happens, the vehicle may
not start. Move the steering wheel from left
to right while attempting to start the
vehicle. If this does not work, the vehicle
needs service.
If the vehicle must be shut off in an
emergency:
1. Brake using a firm and steady pressure. Do not pump the brakes repeatedly. This
may deplete power assist, requiring
increased brake pedal force.
2. Shift the vehicle to N (Neutral). This can be done while the vehicle is moving.
After shifting to N (Neutral), firmly apply
the brakes and steer the vehicle to a
safe location.
3. Come to a complete stop. Hold the brake pedal down and shift to P (Park). The
vehicle must be in P (Park) to turn the
ignition off.
4. Continue to hold the brake pedal down. 5. Set the parking brake. See
Electric
Parking Brake 0240.
6. Press ENGINE START/STOP once to turn the ignition off.
7. Release the brake pedal.
If the vehicle cannot be pulled over, and
must be shut off while driving, press and
hold ENGINE START/STOP for longer than
two seconds, or press twice in five seconds.
ACC/ACCESSORY (Amber Indicator Light) :
This mode allows some electrical accessories
to be used when the engine is off.
With the ignition off, pressing the button
one time without the brake pedal applied
will place the ignition system in ACC/
ACCESSORY.
The ignition will switch from ACC/
ACCESSORY to off after five minutes to
prevent battery rundown.
ON/RUN/START (Green Indicator Light) : This
mode is for driving and starting. With the
ignition off, and the brake pedal applied,
pressing the button once will turn the
ignition on. Once engine cranking begins,
release the button. Engine cranking will
continue until the engine starts. See Starting
the Engine 0228.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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232 Driving and Operating
Warning (Continued)
If unusual fumes are detected or if it is
suspected that exhaust is coming into the
vehicle:
.Drive it only with the windows
completely down.
.Have the vehicle repaired immediately.
Never park the vehicle with the engine
running in an enclosed area such as a
garage or a building that has no fresh air
ventilation.
Running the Vehicle While Parked
It is better not to park with the engine
running.
If the vehicle is left with the engine running,
follow the proper steps to be sure the
vehicle will not move. See Shifting Into Park
0 230 and
Engine Exhaust 0231.
If parking on a hill and pulling a trailer, see
Driving Characteristics and Towing Tips
0 280.
Automatic Transmission
The shift switches are on the center stack.
The selected gear position will illuminate red
on the shift switch, while all others will be
displayed in white. If the shift is not
immediate, as in very cold conditions, the
indicator on the shift switch may blink until
it is fully engaged.
The transmission does not operate when the
vehicle is off.
If the vehicle is in ACC/ACCESSORY, the
transmission can be shifted into P (Park). If ENGINE START/STOP is pressed twice while
at a relatively high speed, the engine will
turn off and the transmission will
automatically shift to N (Neutral). Once the
vehicle is stopped, P (Park) can be selected.
P :
This position locks the drive wheels. Use
P (Park) when starting the engine to prevent
the vehicle from moving easily.
{Warning
It is dangerous to get out of the vehicle
if the transmission is not in P (Park) with
the parking brake set. The vehicle
can roll.
Do not leave the vehicle when the engine
is running. If the engine has been left
running, the vehicle can move suddenly.
You or others could be injured. To be
sure the vehicle will not move, even
when on fairly level ground, always set
the parking brake and place the
transmission into P (Park). See Shifting
Into Park 0230 and
Driving Characteristics and Towing Tips
0 280.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Driving and Operating 233
This vehicle is equipped with an electronic
transmission. The R (Reverse) and D (Drive)
shift switches are designed to prevent
inadvertent shifting out of P (Park) unless
the ignition is on, and the brake pedal is
applied.
When the vehicle is stopped, press ENGINE
START/STOP to turn off the vehicle. The
transmission will shift to P (Park)
automatically.
The vehicle will not shift into P (Park) if it is
moving too fast. Stop the vehicle and shift
into P (Park).
To shift in and out of P (Park), seeShifting
Into Park 0230 and
Shifting out of Park 0230.
R : Use this gear to back up.
If the vehicle is shifted from either
R (Reverse) to D (Drive), or D (Drive) to
R (Reverse) while the speed is too high, the
vehicle will shift to N (Neutral). Reduce the
vehicle speed and try the shift again.
To shift into R (Reverse): 1. Bring the vehicle to a complete stop.
2. Pull the R (Reverse) switch on the center stack.
To shift out of R (Reverse): 1. Bring the vehicle to a complete stop.
2. Shift to the desired gear.
At low vehicle speeds, R (Reverse) can be
used to rock the vehicle back and forth to
get out of snow, ice, or sand without
damaging the transmission. See If the
Vehicle Is Stuck 0221.
N : In this position, the engine does not
connect with the wheels. To restart the
engine when the vehicle is already moving,
use N (Neutral) only.
{Warning
Shifting into a drive gear while the
engine is running at high speed is
dangerous. Unless your foot is firmly on
the brake pedal, the vehicle could move
very rapidly. You could lose control and
hit people or objects. Do not shift into a
drive gear while the engine is running at
high speed.
Caution
Shifting out of P (Park) or N (Neutral) with
the engine running at high speed may
damage the transmission. The repairs
(Continued)
Caution (Continued)
would not be covered by the vehicle
warranty. Be sure the engine is not
running at high speed when shifting the
vehicle.
Caution
The vehicle is not designed to stay in
N (Neutral) for extended periods of time.
It will automatically shift into P (Park).
To shift into N (Neutral), press the
N (Neutral) switch until the N indicator
is red.
To shift out of N (Neutral): 1. Bring the vehicle to a complete stop.
2. Shift to the desired gear.
Car Wash Mode
This vehicle includes a Car Wash Mode that
allows the vehicle to remain in N (Neutral)
for use in automatic car washes.
Car Wash Mode is not to be used for vehicle
towing. If the vehicle needs to be towed,
see Towing the Vehicle 0370

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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236 Driving and Operating
hills or mountain grades, when towing,
or when hauling heavy loads. SeeDriver
Mode Control 0245 to activate Tow/
Haul Mode.
Tow/Haul Mode Grade Braking
Tow/Haul Mode Grade Braking is only
enabled while the Tow/Haul Mode is
selected and the vehicle is not in the Range
Selection Mode. See Manual Mode0235.
Tow/Haul Mode Grade Braking assists in
maintaining desired vehicle speeds when
driving on downhill grades by using the
engine and transmission to slow the vehicle.
See Towing Equipment 0287.
Drive Systems
Four-Wheel Drive
If equipped, four-wheel drive engages the
front axle for extra traction.
Read the appropriate section for transfer
case operation before using.
Caution
Do not drive on clean, dry pavement in 4
mand 4n(if equipped) for an extended
period of time. These conditions may
cause premature wear on the vehicle’s
powertrain.
Driving on clean, dry pavement in 4
mor 4
nmay:
.Cause a vibration to be felt in the
steering system.
.Cause tires to wear faster.
{Warning
If equipped with four-wheel drive, the
vehicle will be free to roll if the transfer
case is in N (Neutral), even when the
transmission is in P (Park). You or
someone else could be seriously injured.
Be sure the transfer case is in a drive
gear —2
m, 4m, or 4n—or set the
parking brake before placing the transfer
case in N (Neutral). See Shifting Into Park
0 230.
Caution
Extended high-speed operation in 4n
may damage or shorten the life of the
drivetrain.
An engagement noise and bump is normal
when shifting between 4
nand 4mor
N (Neutral), with the engine running.
Shifting into 4
nwill turn Traction Control
and StabiliTrak/Electronic Stability Control
(ESC) off. See Traction Control/Electronic
Stability Control 0242.
Automatic Transfer Case
Two-Speed Transfer Case

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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Driving and Operating 237
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:
N (Neutral) :Use only when the vehicle
needs to be towed. See Recreational Vehicle
Towing 0371 or
Towing the Vehicle 0370.
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.
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.
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.
4
n(Four-Wheel Drive Low) : This setting
engages the front axle and delivers extra
torque. Choose 4
nwhen driving off-road in
deep sand, deep mud, or deep snow, and
while climbing or descending steep hills.
While driving in 4
n, keep vehicle speed
below 72 km/h (45 mph).
Shifting into 4
nwill turn Traction Control
and StabiliTrak/ESC off. See Traction Control/
Electronic Stability Control 0242.
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 to
indicate that the 4x4 transfer case has been
requested to shift to the new desired state. Once the 4x4 shift has completed, the DIC
message disappears, the 4x4 graphic stops
flashing, and the current setting is indicated.
When a shift to 2
mis completed successfully
while in P (Park), the parking brake will
engage. To resume driving, shift the
transmission to the desired gear and
manually release the parking brake or press
the accelerator pedal to begin driving. See
Electric Parking Brake 0240.
If equipped, use 4
n, AUTO, or 4mto provide
additional traction when parking on a steep
grade with poor traction such as ice, snow,
mud, or gravel.
Shifting Into 4
n
1. The ignition must be on and the vehicle must be stopped or moving less than
5 km/h (3 mph) with the transmission in
N (Neutral). It is best for the vehicle to
be moving 1.6 to 3.2 km/h (1 to 2 mph).
2. Press 4
n. 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 to indicate that
the 4x4 transfer case has been requested
to shift to the new desired state.