2021 GMC YUKON service

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
66 Seats and Restraints
.Let only qualified technicians work on the
airbag systems. Improper service can
mean that an airbag system will not work
properly. See your dealer for service.
Passenger Sensing System
The vehicle has a passenger sensing system
for the front outboard passenger position.
The passenger airbag status indicator will
light on the overhead console when the
vehicle is started.
United States and Canada
The words ON and OFF, and the symbols for
on and off, will be visible during the system
check. When the system check is complete,
either the word ON or OFF, and the symbol
for on or off, will be visible. See Passenger
Airbag Status Indicator 0110.
The passenger sensing system turns off the
front outboard passenger frontal airbag
under certain conditions. No other airbag is
affected by the passenger sensing system. The passenger sensing system works with
sensors that are part of the front outboard
passenger seat and seat belt. The sensors
are designed to detect the presence of a
properly seated occupant and determine if
the front outboard passenger frontal airbag
should be allowed to inflate or not.
According to accident statistics, children are
safer when properly secured in a rear seat
in the correct child restraint for their weight
and size.
Whenever possible, children aged 12 and
under should be secured in a rear seating
position.
Never put a rear-facing child seat in the
front. This is because the risk to the
rear-facing child is so great, if the airbag
inflates.
{Warning
A child in a rear-facing child restraint can
be seriously injured or killed if the
passenger frontal airbag inflates. This is
because the back of the rear-facing child
restraint would be very close to the
inflating airbag. A child in a
forward-facing child restraint can be
(Continued)
Warning (Continued)
seriously injured or killed if the passenger
frontal airbag inflates and the passenger
seat is in a forward position.
Even if the passenger sensing system has
turned off the passenger frontal airbag,
no system is fail-safe. No one can
guarantee that an airbag will not deploy
under some unusual circumstance, even
though the airbag is turned off.
Never put a rear-facing child restraint in
the front seat, even if the airbag is off.
If securing a forward-facing child restraint
in the front outboard passenger seat,
always move the seat as far back as it
will go. It is better to secure child
restraints in the rear seat. Consider using
another vehicle to transport the child
when a rear seat is not available.
If the vehicle does not have a rear seat that
will accommodate a rear-facing child
restraint, a rear-facing child restraint should
not be installed in the vehicle, even if the
airbag is off.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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Seats and Restraints 67
The passenger sensing system is designed to
turn off the front outboard passenger
frontal airbag if:
.The front outboard passenger seat is
unoccupied.
.The system determines an infant is
present in a child restraint.
.A front outboard passenger takes his/her
weight off of the seat for a period
of time.
When the passenger sensing system has
turned off the front outboard passenger
frontal airbag, the OFF indicator will light
and stay lit as a reminder that the airbag is
off. See Passenger Airbag Status Indicator
0 110.
The passenger sensing system is designed to
turn on the front outboard passenger frontal
airbag anytime the system senses that a
person of adult size is sitting properly in the
front outboard passenger seat.
When the passenger sensing system has
allowed the airbag to be enabled, the ON
indicator will light and stay lit as a reminder
that the airbag is active.
For some children, including children in child
restraints, and for very small adults, the
passenger sensing system may or may not turn off the front outboard passenger
frontal airbag, depending upon the person's
seating posture and body build. Everyone in
the vehicle who has outgrown child
restraints should wear a seat belt
properly
—whether or not there is an
airbag for that person.{Warning
If the airbag readiness light ever comes
on and stays on, it means that
something may be wrong with the airbag
system. To help avoid injury to yourself
or others, have the vehicle serviced right
away. See Airbag Readiness Light 0109
for more information, including important
safety information.
If the On Indicator Is Lit for a Child
Restraint
The passenger sensing system is designed to
turn off the front outboard passenger
frontal airbag if the system determines that
an infant is present in a child restraint. If a
child restraint has been installed and the ON
indicator is lit:
1. Turn the vehicle off. 2. Remove the child restraint from the
vehicle.
3. Remove any additional items from the seat such as blankets, cushions, seat
covers, seat heaters, or seat massagers.
4. Reinstall the child restraint following the directions provided by the child restraint
manufacturer and refer to Securing Child
Restraints (With the Seat Belt in the Rear
Seat) 084 or
Securing Child Restraints (With the Seat
Belt in the Center Front Seat) 088 or
Securing Child Restraints (With the Seat
Belt in the Front Passenger Seat) 086.
Make sure the seat belt retractor is
locked by pulling the shoulder belt all
the way out of the retractor when
installing the child restraint, even if the
child restraint is equipped with a seat
belt lock off. When the retractor lock is
set, the belt can be tightened but not
pulled out of the retractor.
5. If, after reinstalling the child restraint and restarting the vehicle, the ON
indicator is still lit, turn the vehicle off.
Then slightly recline the vehicle seatback
and adjust the seat cushion,

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Seats and Restraints 69
Additional Factors Affecting System
Operation
Seat belts help keep the passenger in
position on the seat during vehicle
maneuvers and braking, which helps the
passenger sensing system maintain the
passenger airbag status. See“Seat Belts”
and “Child Restraints” in the Index for
additional information about the importance
of proper restraint use.
A thick layer of additional material, such as
a blanket or cushion, or aftermarket
equipment such as seat covers, seat heaters,
and seat massagers can affect how well the
passenger sensing system operates. We
recommend that you not use seat covers or
other aftermarket equipment except when
approved by GM for your specific vehicle.
See Adding Equipment to the
Airbag-Equipped Vehicle 069 for more
information about modifications that can
affect how the system operates.
The ON indicator may be lit if an object,
such as a briefcase, handbag, grocery bag,
laptop, or other electronic device, is put on
an unoccupied seat. If this is not desired,
remove the object from the seat.
{Warning
Stowing articles under the passenger seat
or between the passenger seat cushion
and seatback may interfere with the
proper operation of the passenger
sensing system.
Servicing the Airbag-Equipped
Vehicle
Airbags affect how the vehicle should be
serviced. There are parts of the airbag
system in several places around the vehicle.
Your dealer and the service manual have
information about servicing the vehicle and
the airbag system. To purchase a service
manual, see Publication Ordering
Information 0406.
{Warning
For up to 10 seconds after the vehicle is
turned off and the battery is
disconnected, an airbag can still inflate
during improper service. You can be
injured if you are close to an airbag
when it inflates. Avoid yellow connectors.
They are probably part of the airbag
(Continued)
Warning (Continued)
system. Be sure to follow proper service
procedures, and make sure the person
performing work for you is qualified to
do so.
Adding Equipment to the
Airbag-Equipped Vehicle
Adding accessories that change the vehicle's
frame, bumper system, height, front end,
or side sheet metal may keep the airbag
system from working properly.
The operation of the airbag system can also
be affected by changing, including
improperly repairing or replacing, any parts
of the following:
.Airbag system, including airbag modules,
front or side impact sensors, sensing and
diagnostic module, airbag wiring, or front
center console
.Front seats, including stitching, seams or
zippers
.Seat belts
.Steering wheel, instrument panel,
overhead console, ceiling trim, or pillar
garnish trim

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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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.

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Instruments and Controls 95
Instruments and Controls
Controls
Steering Wheel Adjustment . . . . . . . . . . . . 96
Steering Wheel Controls . . . . . . . . . . . . . . . 96
Heated Steering Wheel . . . . . . . . . . . . . . . . . 96
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Windshield Wiper/Washer . . . . . . . . . . . . . . 97
Rear Window Wiper/Washer . . . . . . . . . . . 98
Compass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Power Outlets . . . . . . . . . . . . . . . . . . . . . . . . . 100
Wireless Charging . . . . . . . . . . . . . . . . . . . . . 101
Warning Lights, Gauges, and Indicators
Warning Lights, Gauges, andIndicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Instrument Cluster . . . . . . . . . . . . . . . . . . . . 104
Speedometer . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Odometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Trip Odometer . . . . . . . . . . . . . . . . . . . . . . . . 106
Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Fuel Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Engine Oil Pressure Gauge . . . . . . . . . . . . . 107
Engine Coolant Temperature Gauge . . . 108
Voltmeter Gauge . . . . . . . . . . . . . . . . . . . . . . 108
Seat Belt Reminders . . . . . . . . . . . . . . . . . . . 109
Airbag Readiness Light . . . . . . . . . . . . . . . . 109
Passenger Airbag Status Indicator . . . . . . 110
Charging System Light . . . . . . . . . . . . . . . . . 111 Malfunction Indicator Lamp (Check
Engine Light) . . . . . . . . . . . . . . . . . . . . . . . . . 111
Brake System Warning Light . . . . . . . . . . . 112
Electric Parking Brake Light . . . . . . . . . . . . 113
Service Electric Parking Brake Light . . . . . 113
Antilock Brake System (ABS) Warning Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Four-Wheel-Drive Light . . . . . . . . . . . . . . . . . 114
Hill Descent Control Light . . . . . . . . . . . . . . 114
Lane Keep Assist (LKA) Light . . . . . . . . . . . 114
Vehicle Ahead Indicator . . . . . . . . . . . . . . . . 115
Pedestrian Ahead Indicator . . . . . . . . . . . . . 115
Traction Off Light . . . . . . . . . . . . . . . . . . . . . . 115
Traction Control System (TCS)/Electronic Stability Control Light . . . . . . . . . . . . . . . . 115
Electronic Stability Control (ESC) Off Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Engine Coolant Temperature Warning Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Driver Mode Control Light . . . . . . . . . . . . . 116
Four Corner Air Suspension Light . . . . . . . 117
Tire Pressure Light . . . . . . . . . . . . . . . . . . . . . 118
Engine Oil Pressure Light . . . . . . . . . . . . . . 118
Low Fuel Warning Light . . . . . . . . . . . . . . . . 118
Security Light . . . . . . . . . . . . . . . . . . . . . . . . . . 119
High-Beam On Light . . . . . . . . . . . . . . . . . . . 119
Front Fog Lamp Light . . . . . . . . . . . . . . . . . . 119
Lamps On Reminder . . . . . . . . . . . . . . . . . . . 119
Cruise Control Light . . . . . . . . . . . . . . . . . . . . 119
Door Ajar Light . . . . . . . . . . . . . . . . . . . . . . . . 120
Information Displays
Driver Information Center (DIC) . . . . . . . . 120
Head-Up Display (HUD) . . . . . . . . . . . . . . . . 122
Vehicle Messages
Vehicle Messages . . . . . . . . . . . . . . . . . . . . . . 125
Engine Power Messages . . . . . . . . . . . . . . . 125
Vehicle Speed Messages . . . . . . . . . . . . . . . 126
Vehicle Personalization
Vehicle Personalization . . . . . . . . . . . . . . . . 126
Universal Remote System
Universal Remote System . . . . . . . . . . . . . . 131
Universal Remote System Programming . . . . . . . . . . . . . . . . . . . . . . . . . 131
Universal Remote System Operation . . . 133

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Instruments and Controls 103
OSS Notice Information
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THIS SOFTWARE IS PROVIDED BY THE
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DAMAGE.Warning Lights, Gauges, and
Indicators
Warning lights and gauges can signal that
something is wrong before it becomes
serious enough to cause an expensive repair
or replacement. Paying attention to the
warning lights and gauges could prevent
injury.
Some warning lights come on briefly when
the engine is started to indicate they are
working. When one of the warning lights
comes on and stays on while driving,
or when one of the gauges shows there
may be a problem, check the section that
explains what to do. Waiting to do repairs
can be costly and even dangerous.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
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108 Instruments and Controls
indicates oil pressure outside the normal
operating range, check the vehicle's oil as
soon as possible.
SeeEngine Oil 0315.
Caution
Lack of proper engine oil maintenance
can damage the engine. Driving with the
engine oil low can also damage the
engine. The repairs would not be covered
by the vehicle warranty. Check the oil
level as soon as possible. Add oil if
required, but if the oil level is within the
operating range and the oil pressure is
still low, have the vehicle serviced.
Always follow the maintenance schedule
for changing engine oil.
If the vehicle has a diesel engine, see the
Duramax diesel supplement.
Engine Coolant Temperature
Gauge
Metric
English This gauge measures the temperature of the
vehicle's engine coolant.
While driving under normal operating
conditions, if the needle moves into the red
warning area, the engine is too hot. Pull off
the road, stop the vehicle, and turn off the
engine as soon as possible.
Voltmeter Gauge
When the ignition is on, this gauge indicates
the battery voltage.
When the engine is running, this gauge
shows the condition of the charging system.
The gauge can transition from a higher to
lower or a lower to higher reading. This is
normal. If the vehicle is operating outside

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Instruments and Controls 109
the normal operating range, the charging
system light comes on. SeeCharging System
Light 0111. The voltmeter gauge may also
read lower when in fuel economy mode.
This is normal.
Readings outside the normal operating
range can also occur when a large number
of electrical accessories are operating in the
vehicle and the engine is left idling for an
extended period. This condition is normal
since the charging system is not able to
provide full power at engine idle. As engine
speeds are increased, this condition should
correct itself as higher engine speeds allow
the charging system to create maximum
power.
The vehicle can only be driven for a short
time with the readings outside the normal
operating range. If the vehicle must be
driven, turn off all accessories, such as the
radio and air conditioner.
Readings outside the normal operating
range indicate a possible problem in the
electrical system. Have the vehicle serviced
as soon as possible.Seat Belt Reminders
Driver Seat Belt Reminder Light
There is a driver seat belt reminder light on
the instrument cluster.
When the vehicle is started, this light
flashes and a chime may come on to remind
the driver to fasten their seat belt.
Then the light stays on solid until the belt is
buckled. This cycle may continue several
times if the driver remains or becomes
unbuckled while the vehicle is moving.
If the driver seat belt is buckled, neither the
light nor the chime comes on.
Front Passenger Seat Belt Reminder
Light
The vehicle may have a front passenger seat
belt reminder light near the passenger
airbag status indicator. See Passenger
Sensing System 066.
When the vehicle is started, this light
flashes and a chime may come on to remind
passengers to fasten their seat belt.
Then the light stays on solid until the belt is
buckled. This cycle continues several times if
the front passenger remains or becomes
unbuckled while the vehicle is moving.
If the front passenger seat belt is buckled,
neither the chime nor the light comes on.
The front passenger seat belt reminder light
and chime may come on if an object is put
on the seat such as a briefcase, handbag,
grocery bag, laptop, or other electronic
device. To turn off the reminder light and/or
chime, remove the object from the seat or
buckle the seat belt.
Airbag Readiness Light
This light shows if there is an electrical
problem with the airbag system. The system
check includes the airbag sensor(s),
passenger sensing system (if equipped), the