2018 GMC YUKON AC service

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
Seats and Restraints 93
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 to be drivable after a
moderate crash, there may be
concealed damage that could
make it difficult to safely operate
the vehicle.(Continued)
Warning (Continued)
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 0404
and Event Data Recorders
0 404.
. 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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
Seats and Restraints 95
Warning (Continued)
secure child restraints in the rear
seat. Consider using another
vehicle to transport the child
when a rear seat is not available.
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.
. There is a critical problem with
the airbag system or the
passenger sensing system.
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 0145. 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 0144 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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
98 Seats and Restraints
Warning (Continued)
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
Service Publications Ordering
Information0401.
{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
(Continued)
Warning (Continued)
are close to an airbag when it
inflates. Avoid yellow connectors.
They are probably part of the
airbag 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
any parts of the front seats, seat
belts, airbag sensing and diagnostic
module, steering wheel, instrument
panel, inner door seals including the
speakers, any of the airbag
modules, ceiling or pillar garnish
trim, overhead console, front sensors, side impact sensors,
airbag wiring, or front center
console.
Your dealer and the service manual
have information about the location
of the airbag sensors, sensing and
diagnostic module, and airbag
wiring.
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

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
Seats and Restraints 99
turning off the passenger airbag(s).
SeePassenger Sensing System
0 93.
If the vehicle has rollover roof-rail
airbags, see Different Size Tires
and Wheels 0341 for additional
important information.
If you have to modify your vehicle
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
0 394.
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 0144.
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? 089. 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
(Continued)
Warning (Continued)
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 0144.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
130 Instruments and Controls
Auto Set requires an active OnStar
service plan.
If auto timing is set, the time
displayed on the clock may not
update immediately when driving
into a new time zone.
To set the clock display:1. Select SETTINGS from the Home Page, then select Time
and Date.
2. Select Clock Display.
3. Turn the MENU knob to Off or On.
4. Press the MENU knob to select.
Press
oBACK to go to the last
menu and save the changes.
Setting the Time and Date with
Infotainment Display Controls
To set the time:
1. Touch SETTINGS on the Home Page, then touch Time
and Date. 2. Touch Set Time, then touch
«
orªto increase or decrease
hours, minutes, and AM or PM.
Touch 12–24 Hr for 12 or
24 hour clock.
3. Touch
Sto go back to the
previous menu.
Auto Set requires an active OnStar
service plan.
If auto timing is set, the time
displayed on the clock may not
update immediately when driving
into a new time zone.
To set the date: 1. Touch SETTINGS on the Home Page, then touch Time
and Date.
2. Touch Set Date, then touch
«
orªto increase or decrease
month, day, or year.
3. Touch
Sto go back to the
previous menu. To set the clock display:
1. Touch SETTINGS on the Home Page, then touch Time
and Date.
2. Touch Clock Display, then touch Off or On to turn the
clock display off or on.
3. Touch
Sto go back to the
previous menu.
Power Outlets
Power Outlets 12-Volt Direct
Current
Accessory power outlets can be
used to plug in electrical equipment,
such as a cell phone, MP3
player, etc.
The vehicle may have up to five
accessory power outlets:
Vehicles with a Center Console
. One in front of the cupholders on
the center console
. One inside the center storage
console

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
Instruments and Controls 135
SERVICES; LOSS OF USE, DATA,
OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY
OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF
THE USE OF THIS SOFTWARE,
EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH 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./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
140 Instruments and Controls
Fuel Gauge
English Standard Theme Shown,Metric Similar
When the ignition is on, the fuel
gauge indicates about how much
fuel is left in the tank.
There is an arrow near the fuel
gauge pointing to the side of the
vehicle the fuel door is on.
When the indicator nears empty, the
low fuel light comes on. There still is
a little fuel left, but the vehicle
should be refueled soon. Here are four things that some
owners ask about. None of these
show a problem with the fuel gauge:
.
At the service station, the fuel
pump shuts off before the gauge
reads full.
. It takes a little more or less fuel
to fill up than the gauge
indicated. For example, the
gauge may have indicated the
tank was half full, but it actually
took a little more or less than
half the tank's capacity to fill
the tank.
. The gauge moves a little while
turning a corner or speeding up.
. The gauge takes a few seconds
to stabilize after the ignition is
turned on, and goes back to
empty when the ignition is
turned off.
Engine Oil Pressure
Gauge
Metric Standard Theme

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
Instruments and Controls 141
English Standard Theme
The engine oil pressure gauge
shows the engine oil pressure
in kPa (kilopascals) or psi (pounds
per square inch) when the engine is
running.
Oil pressure can vary with engine
speed, outside temperature, and oil
viscosity.
A reading outside the normal
operating range can be caused by a
dangerously low oil level or some
other problem causing low oil
pressure. Check the vehicle's oil as soon as possible. An oil pressure
message may display. See
Engine
Oil 0287.
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.
Engine Coolant
Temperature Gauge
Metric Standard Theme