Page 44 of 425

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Keys, Doors, and Windows 43This can be manually overridden by
pressing and holding
Q on the
power door lock switch.
Keyless Access : When locking is
requested with the driver door open
and the vehicle is on or in ACC/
ACCESSORY, all the doors will lock
and then the driver door will unlock.
If the vehicle is off and locking is
requested while a door is open,
when all doors are closed the
vehicle will check for RKE
transmitters inside. If an RKE
transmitter is detected and the
number of RKE transmitters inside
has not reduced, the driver door will
unlock and the horn will sound three
times.
This can be manually overridden by
pressing and holding
Q on the
power door lock switch.
Unlocked Door Anti-Lockout
If Unlocked Door Anti-Lockout is
turned on and the vehicle is off, the
driver door is open, and locking is
requested, all the doors will lock and
the driver door will remain open.
Press the button again to lock the driver door. The Unlocked Door
Anti-Lockout feature can be turned
on or off. See Vehicle
Personalization 0 158 .
Safety Locks The rear door safety locks prevent
passengers from opening the rear
doors from inside the vehicle.
Press
{ to activate the safety locks
on the rear doors. The indicator light
comes on when activated.
Press
{ again to deactivate the
safety locks. Doors Liftgate
{ WarningExhaust gases can enter the
vehicle if it is driven with the
liftgate or trunk/hatch open,
or with any objects that pass
through the seal between the
body and the trunk/hatch or
liftgate. Engine exhaust contains
carbon monoxide (CO) which
cannot be seen or smelled. It can
cause unconsciousness and even
death.
If the vehicle must be driven with
the liftgate or trunk/hatch open:
.
Close all of the windows.
.
Fully open the air outlets on
or under the instrument
panel.
.
Adjust the climate control
system to a setting that
brings in only outside air
(Continued)
Page 259 of 425

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/21/17
258 Driving and Operating Filling the Tank with a Portable
Gas Can
If the vehicle runs out of fuel and
must be filled from a portable
gas can:
1. Locate the capless funnel
adapter from inside the vehicle.
2. Insert and latch the funnel into
the capless fuel system.
{ Warning
Attempting to refuel without using
the funnel adapter may cause fuel
spillage and damage the capless
fuel system. This could cause a
fire and you or others could be
badly burned and the vehicle
could be damaged. 3. Remove and clean the funnel
adapter and return to the
storage location.
Filling a Portable Fuel
Container
{ WarningFilling a portable fuel container
while it is in the vehicle can cause
fuel vapors that can ignite either
by static electricity or other
means. You or others could be
badly burned and the vehicle
could be damaged. Always:
.
Use approved fuel
containers.
.
Remove the container from
the vehicle, trunk, or pickup
bed before filling.
.
Place the container on the
ground.
.
Place the nozzle inside the
fill opening of the container
before dispensing fuel, and
(Continued) Warning (Continued) keep it in contact with the fill
opening until filling is
complete.
.
Fill the container no more
than 95% full to allow for
expansion.
.
Do not smoke, light
matches, or use lighters
while pumping fuel.
.
Avoid using cell phones or
other electronic devices.
Page 260 of 425

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/21/17
Driving and Operating 259
Trailer Towing General Towing
Information Only use towing equipment that has
been designed for the vehicle.
Contact your dealer or trailering
dealer for assistance with preparing
the vehicle for towing a trailer. Read
the entire section before towing a
trailer.
For towing a disabled vehicle, see
Towing the Vehicle 0 355 . For
towing the vehicle behind another
vehicle such as a motor home, see
Recreational Vehicle Towing 0 355 .
Driving Characteristics
and Towing Tips Driving with a Trailer
When towing a trailer:
.
Become familiar with the state
and local laws that apply to
trailer towing. These
requirements vary from state to
state. .
The trailer must be equipped
with brakes adequate for the
intended use. A loaded trailer
weighing more than 900 kg
(2,000 lb) must be equipped with
its own brake system, with
brakes working on all axles.
Trailer braking equipment
conforming to Canadian
Standards Association (CSA)
requirement CAN3-D313, or its
equivalent, is recommended.
.
Do not tow a trailer during the
first 800 km (500 mi) to prevent
damage to the engine, axle,
or other parts.
.
Then during the first 800 km
(500 mi) of trailer towing, do not
drive over 80 km/h (50 mph) and
do not make starts at full throttle.
.
Vehicles can tow in D (Drive).
Shift the transmission to a lower
gear if the transmission shifts
too often under heavy loads and/
or hilly conditions.
.
Do not use Adaptive Cruise
Control when towing. .
Turn off Parking Assist and Rear
Cross Traffic Alert (RTCA) when
towing.
.
The Forward Automatic Braking
System should be set to Off
when towing. See Forward
Automatic Braking (FAB) 0 21 .
.
Turn off Lane Keep Assist (LKA)
when towing. See Lane Keep
Assist (LKA) 0 252 .
{ WarningWhen towing a trailer, exhaust
gases may collect at the rear of
the vehicle and enter if the
liftgate, trunk/hatch, or rear-most
window is open.
When towing a trailer:
.
Do not drive with the
liftgate, trunk/hatch,
or rear-most window open.
.
Fully open the air outlets on
or under the instrument
panel.
(Continued)
Page 306 of 425

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Vehicle Care 305Driver Assistance Systems When a windshield replacement is
needed and the vehicle is equipped
with a front-looking camera sensor
for the Driver Assistance Systems,
the windshield must be installed
according to GM specifications for
these systems to work properly. If it
is not, there may be unexpected
behavior and/or messages from
these systems.
Gas Strut(s) This vehicle is equipped with gas
strut(s) to provide assistance in
lifting and holding open the hood/
trunk/liftgate system in full open
position.
{ Warning
If the gas struts that hold open
the hood, trunk, and/or liftgate fail,
you or others could be seriously
injured. Take the vehicle to your
dealer for service immediately.
Visually inspect the gas struts for
(Continued) Warning (Continued) signs of wear, cracks, or other
damage periodically. Check to
make sure the hood/trunk/liftgate
is held open with enough force.
If struts are failing to hold the
hood/trunk/liftgate, do not
operate. Have the vehicle
serviced.
CautionDo not apply tape or hang any
objects from gas struts. Also do
not push down or pull on gas
struts. This may cause damage to
the vehicle.
See Maintenance Schedule 0 370 . Hood
Trunk