break 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
64 Seats and Restraints
the impact, when either side of the vehicle
is struck. In addition, the front center airbag
is designed to inflate when the sensing
system predicts that the vehicle is about to
roll over on its side. The front center airbag
is not designed to inflate in frontal impacts,
near frontal impacts, or rear impacts.
Seat-mounted side impact airbags are
designed to inflate in moderate to severe
side crashes, depending on the location of
the impact. Seat-mounted side impact
airbags are not designed to inflate in
rollovers or in rear impacts. The driver side
seat-mounted side impact airbag is not
designed to inflate in frontal impacts or in
near frontal impacts. The passenger side
seat-mounted side impact airbag is designed
to inflate in moderate to severe frontal
impacts or in near frontal impacts.
A seat-mounted side impact airbag is
designed to inflate on the side of the vehicle
that is struck.
Roof-rail airbags are designed to inflate in
moderate to severe side crashes depending
on the location of the impact. In addition,
these roof-rail airbags are designed to inflate
during a rollover or in a severe frontal
impact. Roof-rail airbags are not designed to
inflate in rear impacts. Both roof-rail airbagswill inflate when either side of the vehicle is
struck, if the sensing system predicts that
the vehicle is about to roll over on its side,
or in a severe frontal impact.
In any particular crash, no one can say
whether an airbag should have inflated
simply because of the vehicle damage or the
repair costs.
What Makes an Airbag Inflate?
In a deployment event, the sensing system
sends an electrical signal triggering a release
of gas from the inflator. Gas from the
inflator fills the airbag causing the bag to
break out of the cover. The inflator, the
airbag, and related hardware are all part of
the airbag module.
For airbag locations, see
Where Are the
Airbags? 062.
How Does an Airbag Restrain?
In moderate to severe frontal or near frontal
collisions, even belted occupants can contact
the steering wheel or the instrument panel.
In moderate to severe side collisions, even
belted occupants can contact the inside of
the vehicle. Airbags supplement the protection provided
by seat belts by distributing the force of the
impact more evenly over the
occupant's body.
Rollover capable roof-rail airbags are
designed to help contain the head and chest
of occupants in the outboard seating
positions in the first, second, and third rows.
The rollover capable roof-rail airbags are
designed to help reduce the risk of full or
partial ejection in rollover events, although
no system can prevent all such ejections.
But airbags would not help in many types
of collisions, primarily because the
occupant's motion is not toward those
airbags. See
When Should an Airbag Inflate?
0 63.
Airbags should never be regarded as
anything more than a supplement to seat
belts.What Will You See after an
Airbag Inflates?
After frontal and seat-mounted side impact
airbags inflate, they quickly deflate, so
quickly that some people may not even
realize the airbags inflated. The front center
airbag and roof-rail airbags may still be at

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Seats and Restraints 65
least partially inflated for some time after
they inflate. Some components of the airbag
module may be hot for several minutes. For
location of the airbags, seeWhere Are the
Airbags? 062.
The parts of the airbag that come into
contact with you may be warm, but not too
hot to touch. There may be some smoke
and dust coming from the vents in the
deflated airbags. Airbag inflation does not
prevent the driver from seeing out of the
windshield or being able to steer the
vehicle, nor does it prevent people from
leaving the vehicle.
{Warning
When an airbag inflates, there may be
dust in the air. This dust could cause
breathing problems for people with a
history of asthma or other breathing
trouble. To avoid this, everyone in the
vehicle should get out as soon as it is
safe to do so. If you have breathing
problems but cannot get out of the
vehicle after an airbag inflates, then get
fresh air by opening a window or a door. (Continued)
Warning (Continued)
If you experience breathing problems
following an airbag deployment, you
should seek medical attention.
The vehicle has a feature that may
automatically unlock the doors, turn on the
interior lamps and hazard warning flashers,
and shut off the fuel system after the
airbags inflate. The feature may also
activate, without airbag inflation, after an
event that exceeds a predetermined
threshold. After turning the ignition off and
then on again, the fuel system will return to
normal operation; the doors can be locked,
the interior lamps can be turned off, and
the hazard warning flashers can be turned
off using the controls for those features.
If any of these systems are damaged in the
crash they may not operate as normal.
{Warning
A crash severe enough to inflate the
airbags may have also damaged
important functions in the vehicle, such
as the fuel system, brake and steering
systems, etc. Even if the vehicle appears (Continued)
Warning (Continued)
to be drivable after a moderate crash,
there may be concealed damage that
could make it difficult to safely operate
the vehicle.
Use caution if you should attempt to
restart the engine after a crash has
occurred.
In many crashes severe enough to inflate
the airbag, windshields are broken by
vehicle deformation. Additional windshield
breakage may also occur from the front
outboard passenger airbag.
.Airbags are designed to inflate only once.
After an airbag inflates, you will need
some new parts for the airbag system.
If you do not get them, the airbag
system will not be there to help protect
you in another crash. A new system will
include airbag modules and possibly other
parts. The service manual for the vehicle
covers the need to replace other parts.
.The vehicle has a crash sensing and
diagnostic module which records
information after a crash. See Vehicle
Data Recording and Privacy 0408 and
Event Data Recorders 0409.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
70 Seats and Restraints
.Inner door seals, including speakers
Your dealer and the service manual have
information about the location of the airbag
modules and sensors, sensing and diagnostic
module, and airbag wiring along with the
proper replacement procedures.
In addition, the vehicle has a passenger
sensing system for the front outboard
passenger position, which includes sensors
that are part of the passenger's seat. The
passenger sensing system may not operate
properly if the original seat trim is replaced
with non-GM covers, upholstery, or trim,
or with GM covers, upholstery, or trim
designed for a different vehicle. Any object,
such as an aftermarket seat heater or a
comfort enhancing pad or device, installed
under or on top of the seat fabric, could
also interfere with the operation of the
passenger sensing system. This could either
prevent proper deployment of the passenger
airbag(s) or prevent the passenger sensing
system from properly turning off the
passenger airbag(s). See Passenger Sensing
System 066.
If the vehicle has rollover roof-rail airbags,
see Different Size Tires and Wheels 0352 for
additional important information. If the vehicle must be modified because you
have a disability and you have questions
about whether the modifications will affect
the vehicle's airbag system, or if you have
questions about whether the airbag system
will be affected if the vehicle is modified for
any other reason, call Customer Assistance.
See
Customer Assistance Offices 0401.
Airbag System Check
The airbag system does not need regularly
scheduled maintenance or replacement.
Make sure the airbag readiness light is
working. See Airbag Readiness Light 0109.
Caution
If an airbag covering is damaged, opened,
or broken, the airbag may not work
properly. Do not open or break the airbag
coverings. If there are any opened or
broken airbag coverings, have the airbag
covering and/or airbag module replaced.
For the location of the airbags, see Where
Are the Airbags? 062. See your dealer
for service.
Replacing Airbag System Parts
after a Crash
{Warning
A crash can damage the airbag systems
in the vehicle. A damaged airbag system
may not properly protect you and your
passenger(s) in a crash, resulting in
serious injury or even death. To help
make sure the airbag systems are
working properly after a crash, have
them inspected and any necessary
replacements made as soon as possible.
If an airbag inflates, you will need to
replace airbag system parts. See your dealer
for service.
If the airbag readiness light stays on after
the vehicle is started or comes on when you
are driving, the airbag system may not work
properly. Have the vehicle serviced right
away. See Airbag Readiness Light 0109.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Seats and Restraints 81
For models with bucket second row seating,
the top tether anchors are on the rear of
the seatback for each seating position in the
second row. Be sure to use an anchor
located directly behind the seating position
where the child restraint will be placed.
Third Row Seat
}:Seating positions with top tether
anchors.
For the third row seat, the top tether
anchors are on the back of the seatback. Be
sure to use an anchor located directly
behind the seating position where the child
restraint will be placed.
Do not secure a child restraint in a position
without a top tether anchor if a national or
local law requires that the top tether be
attached, or if the instructions that come
with the child restraint say that the top
tether must be attached.
According to accident statistics, children and
infants are safer when properly restrained in
a child restraint system or infant restraint
system secured in a rear seating position.
See Where to Put the Restraint 076 for
additional information.
Securing a Child Restraint Designed for
the LATCH System
{Warning
A child could be seriously injured or killed
in a crash if the child restraint is not
properly attached to the vehicle using
either the LATCH anchors or the vehicle
seat belt. Follow the instructions that
came with the child restraint and the
instructions in this manual.
{Warning
To reduce the risk of serious or fatal
injuries during a crash, do not attach
more than one child restraint to a single
anchor. Attaching more than one child
restraint to a single anchor could cause
the anchor or attachment to come loose
or even break during a crash. A child or
others could be injured.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
138 Lighting
Turn and Lane-Change Signals
An arrow on the instrument cluster flashes
in the direction of the turn or lane change.
Move the turn signal lever all the way up or
down to signal a turn.
Raise or lower the lever for less than
one second until the arrow starts to flash to
signal a lane change. This causes the turn
signals to automatically flash three times.
It will flash six times if Tow/Haul Mode is
active. Holding the turn signal lever for
more than one second will cause the turn
signals to flash until the lever is released.
The lever returns to its starting position
whenever it is released.
If after signaling a turn or a lane change the
arrows flash rapidly or do not come on, a
signal bulb could be burned out.Replace any burned out bulbs. If a bulb is
not burned out, check the fuse. See
Fuses
and Circuit Breakers 0331.
Turn Signal On Chime
If the turn signal is left on for more than
1.2 km (0.75 mi), a chime sounds at each
flash of the turn signal. The message TURN
SIGNAL ON will also appear in the Driver
Information Center (DIC). To turn the chime
and message off, move the turn signal lever
to the off position.
Fog Lamps
If equipped with fog lamps, the button is on
the exterior lamp control, to the left of the
steering column. The ignition must be on for the fog lamps
to come on.
#:
Press to turn the fog lamps on or off.
A light will come on in the instrument
cluster.
When the fog lamps are turned on, the
parking lamps automatically turn on.
When the headlamps are changed to high
beam, the fog lamps also go off. When the
high-beam headlamps are turned off, the fog
lamps will come on again.
Some localities have laws that require the
headlamps to be on with the fog lamps.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
212 Driving and Operating
Driving and Operating
Driving Information
Driving for Better Fuel Economy . . . . . . . 213
Distracted Driving . . . . . . . . . . . . . . . . . . . . . . 213
Defensive Driving . . . . . . . . . . . . . . . . . . . . . . 214
Impaired Driving . . . . . . . . . . . . . . . . . . . . . . . 214
Control of a Vehicle . . . . . . . . . . . . . . . . . . . 214
Braking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
Steering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Off-Road Recovery . . . . . . . . . . . . . . . . . . . . . 215
Loss of Control . . . . . . . . . . . . . . . . . . . . . . . . 216
Off-Road Driving . . . . . . . . . . . . . . . . . . . . . . . 216
Driving on Wet Roads . . . . . . . . . . . . . . . . . 219
Hill and Mountain Roads . . . . . . . . . . . . . . 220
Winter Driving . . . . . . . . . . . . . . . . . . . . . . . . . 221
If the Vehicle Is Stuck . . . . . . . . . . . . . . . . . . 221
Vehicle Load Limits . . . . . . . . . . . . . . . . . . . . 222
Starting and Operating
New Vehicle Break-In . . . . . . . . . . . . . . . . . . 226
Ignition Positions . . . . . . . . . . . . . . . . . . . . . . 226
Starting the Engine . . . . . . . . . . . . . . . . . . . . 228
Stop/Start System . . . . . . . . . . . . . . . . . . . . . 229
Retained Accessory Power (RAP) . . . . . . . 229
Shifting Into Park . . . . . . . . . . . . . . . . . . . . . 230
Shifting out of Park . . . . . . . . . . . . . . . . . . . 230
Parking over Things That Burn . . . . . . . . . 231
Dynamic Fuel Management . . . . . . . . . . . . 231
Extended Parking . . . . . . . . . . . . . . . . . . . . . . 231
Engine Exhaust
Engine Exhaust . . . . . . . . . . . . . . . . . . . . . . . . 231
Running the Vehicle While Parked . . . . . 232
Automatic Transmission
Automatic Transmission . . . . . . . . . . . . . . . 232
Manual Mode . . . . . . . . . . . . . . . . . . . . . . . . . 235
Tow/Haul Mode . . . . . . . . . . . . . . . . . . . . . . . 235
Drive Systems
Four-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . 236
Brakes
Electric Brake Boost . . . . . . . . . . . . . . . . . . . 240
Antilock Brake System (ABS) . . . . . . . . . . 240
Electric Parking Brake . . . . . . . . . . . . . . . . . 240
Brake Assist . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
Hill Start Assist (HSA) . . . . . . . . . . . . . . . . . 242
Ride Control Systems
Traction Control/Electronic StabilityControl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
Hill Descent Control (HDC) . . . . . . . . . . . . 244
Driver Mode Control . . . . . . . . . . . . . . . . . . . 245
Magnetic Ride Control . . . . . . . . . . . . . . . . . 247
Locking Rear Axle . . . . . . . . . . . . . . . . . . . . . 248
Four Corner Air Suspension System . . . 248
Cruise Control
Cruise Control . . . . . . . . . . . . . . . . . . . . . . . . . . 251
Adaptive Cruise Control (Advanced) . . . . 253
Driver Assistance Systems
Driver Assistance Systems . . . . . . . . . . . . . 260
Assistance Systems for Parking or Backing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
Rear Pedestrian Alert . . . . . . . . . . . . . . . . . . 266
Assistance Systems for Driving . . . . . . . . 267
Forward Collision Alert (FCA) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
Automatic Emergency Braking (AEB) . . . . . . . . . . . . . . . . . . . . . . . . 269
Front Pedestrian Braking (FPB) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
Side Blind Zone Alert (SBZA) . . . . . . . . . . . 272
Lane Change Alert (LCA) . . . . . . . . . . . . . . . 272
Lane Keep Assist (LKA) . . . . . . . . . . . . . . . . . 275
Fuel
Top Tier Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . 276
Recommended Fuel (5.3L Engine) . . . . . . 277
Recommended Fuel (6.2L Engine) . . . . . . 277
Prohibited Fuels . . . . . . . . . . . . . . . . . . . . . . . 277
Fuels in Foreign Countries . . . . . . . . . . . . . 278
Fuel Additives . . . . . . . . . . . . . . . . . . . . . . . . . 278
Filling the Tank . . . . . . . . . . . . . . . . . . . . . . . . 278
Filling a Portable Fuel Container . . . . . . . 279
Trailer Towing
General Towing Information . . . . . . . . . . 280
Driving Characteristics and Towing Tips . . . . . . . . . . . . . . . . . . . . . . . . . 280
Trailer Towing . . . . . . . . . . . . . . . . . . . . . . . . . 284

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 223
{Warning
Do not load the vehicle any heavier
than the Gross Vehicle Weight Rating
(GVWR), or either the maximum
front or rear Gross Axle Weight
Rating (GAWR). This can cause
systems to break and change the
way the vehicle handles. This could
cause loss of control and a crash.
Overloading can also reduce stopping
performance, damage the tires, and
shorten the life of the vehicle.
Tire and Loading Information Label
Label Example
A vehicle specific Tire and Loading
Information label is attached to the
center pillar (B-pillar). The tire and
loading information label shows the
number of occupant seating
positions (1), and the maximum vehicle
capacity weight (2) in kilograms and
pounds.
The Tire and Loading Information label
also shows the size of the original
equipment tires (3) and the
recommended cold tire inflation
pressures (4). For more information on
tires and inflation see Tires0339 and
Tire Pressure 0344.
There is also important loading
information on the vehicle Certification/
Tire label. It may show the Gross
Vehicle Weight Rating (GVWR) and the
Gross Axle Weight Rating (GAWR) for
the front and rear axles. See
“Certification/Tire Label” later in this
section. “Steps for Determining Correct Load
Limit–
1.Locate the statement "The combined
weight of occupants and cargo
should never exceed XXX kg or
XXX lbs." on your vehicle’s placard.
2.Determine the combined weight of
the driver and passengers that will
be riding in your vehicle.
3.Subtract the combined weight of the
driver and passengers from XXX kg
or XXX lbs.
4.The resulting figure equals the
available amount of cargo and
luggage load capacity. For example,
if the "XXX" amount equals 1400 lbs.
and there will be five 150 lb
passengers in your vehicle, the
amount of available cargo and
luggage load capacity is 650 lbs.
(1400-750 (5 x 150) = 650 lbs.)
5.Determine the combined weight of
luggage and cargo being loaded on
the vehicle. That weight may not

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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Driving and Operating 225
Certification/Tire Label
A vehicle specific Certification/Tire label
is attached to the center pillar (B-pillar).
The label may shows the size of the
vehicle's original tires and the inflation
pressures needed to obtain the gross
weight capacity of the vehicle. This is
called Gross Vehicle Weight Rating
(GVWR). The GVWR includes the weight
of the vehicle, all occupants, fuel, and
cargo.
The Certification/Tire label also may
show the maximum weights for the
front and rear axles, called Gross Axle
Weight Rating (GAWR). To find out theactual loads on the front and rear axles,
weigh the vehicle at a weigh station.
Your dealer can help with this. Be sure
to spread your load equally on both
sides of the centerline.
The Certification/Tire label may also
include information about the Front
Axle Reserve Capacity.
{Warning
Do not load the vehicle any heavier
than the Gross Vehicle Weight Rating
(GVWR), or either the maximum
front or rear Gross Axle Weight
Rating (GAWR). This can cause
systems to break and change the
way the vehicle handles. This could
cause loss of control and a crash.
Overloading can also reduce stopping
performance, damage the tires, and
shorten the life of the vehicle. Caution
Overloading the vehicle may cause
damage. Repairs would not be covered by
the vehicle warranty. Do not overload the
vehicle.
The label will help decide how much
cargo and installed equipment the truck
can carry.
Using heavier suspension components
to get added durability might not
change the weight ratings. Ask your
dealer to help load the vehicle the
right way.
{Warning
Things you put inside the vehicle can
strike and injure people in a sudden
stop or turn, or in a crash.
.Put things in the cargo area of the
vehicle. Try to spread the weight
evenly.
(Continued)

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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226 Driving and Operating
Warning (Continued)
.Never stack heavier things, like
suitcases, inside the vehicle so
that some of them are above the
tops of the seats.
.Do not leave an unsecured child
restraint in the vehicle.
.When you carry something inside
the vehicle, secure it whenever
you can.
.Do not leave a seat folded down
unless you need to.
There is also important loading
information for off-road driving in this
manual. See “Loading Your Vehicle for
Off-Road Driving” underOff-Road
Driving 0216.
Starting and Operating
New Vehicle Break-In
Caution
The vehicle does not need an elaborate
break-in. But it will perform better in the
long run if you follow these guidelines:
.Keep the vehicle speed at 88 km/h
(55 mph) or less for the first 805 km
(500 mi).
.Do not drive at any one constant
speed, fast or slow, for the first
805 km (500 mi). Do not make
full-throttle starts. Avoid downshifting
to brake or slow the vehicle.
.Avoid making hard stops for the first
322 km (200 mi) or so. During this
time the new brake linings are not yet
broken in. Hard stops with new linings
can mean premature wear and earlier
replacement. Follow this breaking-in
guideline every time you get new
brake linings.
(Continued)
Caution (Continued)
.Do not tow a trailer during break-in.
See Trailer Towing 0284 for the
trailer towing capabilities of the
vehicle and more information.
Following break-in, engine speed and load
can be gradually increased.
Ignition Positions
Vehicles equipped with Keyless Access have
pushbutton starting.
The Remote Key must be in the vehicle for
the system to operate. If the pushbutton
start is not working, the vehicle may be
near a strong radio antenna signal causing