2017 GMC YUKON warning

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 11/9/16
Driving and Operating 267
The starting characteristics of E85
or FlexFuel make it unsuitable for
use when temperatures fall below
−18 °C (0 °F). Use gasoline or add
gasoline to the E85 or FlexFuel.
Because E85 or FlexFuel has less
energy per liter (gallon) than
gasoline, the vehicle will need to be
refilled more often. SeeFilling the
Tank 0267.
Caution
Some additives are not
compatible with E85 or FlexFuel
and can harm the vehicle's fuel
system. Do not add anything to
E85 or FlexFuel. Damage caused
by additives would not be covered
by the vehicle warranty.
Caution
Do not use fuel containing
methanol. It can corrode metal
parts in the fuel system and also
(Continued)
Caution (Continued)
damage plastic and rubber parts.
That damage would not be
covered under the vehicle
warranty.
Filling the Tank
{Warning
Fuel vapors and fuel fires burn
violently and can cause injury or
death.
. To help avoid injuries to you
and others, read and follow
all the instructions on the
fuel pump island.
. Turn off the engine when
refueling.
. Keep sparks, flames, and
smoking materials away
from fuel.
. Do not leave the fuel pump
unattended.
(Continued)
Warning (Continued)
.Do not use a cell phone
while refueling.
. Do not reenter the vehicle
while pumping fuel.
. Keep children away from
the fuel pump and never let
children pump fuel.
. Fuel can spray out if the
refueling nozzle is inserted
too quickly. This spray can
happen if the tank is nearly
full, and is more likely in hot
weather. Insert the refueling
nozzle slowly and wait for
any hiss noise to stop prior
to beginning to flow fuel.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 11/9/16
268 Driving and Operating
To open the fuel door, push and
release the rearward center edge of
the door.
The vehicle has a capless refueling
system and does not have a fuel
cap. The filling nozzle must be fully
inserted and latched prior to starting
fuel flow.
{Warning
Overfilling the fuel tank by more
than three clicks of a standard fill
nozzle may cause:(Continued)
Warning (Continued)
.Vehicle performance issues,
including engine stalling and
damage to the fuel system.
. Fuel spills.
. Potential fuel fires.
Be careful not to spill fuel. Wait a
few seconds after you have finished
pumping before removing the
nozzle. Clean fuel from painted
surfaces as soon as possible. See
Exterior Care 0366.
{Warning
If a fire starts while you are
refueling, do not remove the
nozzle. Shut off the flow of fuel by
shutting off the pump or by
notifying the station attendant.
Leave the area immediately. 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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 11/9/16
Driving and Operating 269
3. Remove and clean the funneladapter and return to the
storage location.
Filling a Portable Fuel
Container
{Warning
Filling 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.
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 0361. For
towing the vehicle behind another
vehicle such as a motor home, see
Recreational Vehicle Towing 0362.
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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 11/9/16
270 Driving and Operating
.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 when
towing.
. The Forward Automatic Braking
System should be set to Off
when towing. See Forward
Automatic Braking (FAB) 021.
{Warning
When 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.
. Also adjust the climate
control system to a setting
that brings in only outside
air. See “Climate Control
Systems” in the Index.
(Continued)
Warning (Continued)
For more information about
carbon monoxide, see Engine
Exhaust 0228.
Towing a trailer requires a certain
amount of experience. The
combination you are driving is
longer and not as responsive as the
vehicle itself. Get acquainted with
the handling and braking of the rig
before setting out for the open road.
The structure, tires, and brakes of
the trailer must be rated to carry the
load. Inadequate trailer equipment
can cause the combination to
operate in an unexpected or unsafe
manner.
Before starting, check all trailer hitch
parts and attachments, safety
chains, electrical connectors, lamps,
tires, and mirrors. Get familiar with
the handling and braking of the rig.
If the trailer has electric brakes, start
the combination moving and then
apply the trailer brake controller by
hand to be sure the brakes work.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 11/9/16
Driving and Operating 271
During the trip, check occasionally
to be sure that the load is secure
and the lamps and any trailer
brakes still work.
Following Distance
Stay at least twice as far behind the
vehicle ahead as you would when
driving the vehicle without a trailer.
This can help to avoid heavy
braking and sudden turns.
Passing
More passing distance is needed
when towing a trailer. The
combination will not accelerate as
quickly and is longer so it is
necessary to go much farther
beyond the passed vehicle before
returning to the lane.
Backing Up
Hold the bottom of the steering
wheel with one hand. To move the
trailer to the left, move that hand to
the left. To move the trailer to the
right, move your hand to the right.
Always back up slowly and,
if possible, have someone
guide you.
Making TurnsCaution
Making very sharp turns while
trailering could cause the trailer to
come in contact with the vehicle.
The vehicle could be damaged.
Avoid making very sharp turns
while trailering.
When turning with a trailer, make
wider turns than normal. Do this so
the trailer will not strike soft
shoulders, curbs, road signs, trees,
or other objects. Avoid jerky or
sudden maneuvers. Signal well in
advance.
If the trailer turn signal bulbs burn
out, the arrows on the instrument
cluster will still flash for turns. It is
important to check occasionally to
be sure the trailer bulbs are still
working.
Driving on Grades
Reduce speed and shift to a lower
gear before starting down a long or
steep downgrade. If the transmission is not shifted down, the
brakes might get hot and no longer
work well.
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.
When towing, use the Tow/Haul
Mode to prevent damage to the
engine or transmission. See
Tow/
Haul Mode 0234.
When towing at high altitude on
steep uphill grades, consider the
following: Engine coolant will boil at
a lower temperature than at normal
altitudes. If the engine is turned off
immediately after towing at high
altitude on steep uphill grades, the
vehicle may show signs similar to
engine overheating. To avoid this,
let the engine run while parked,
preferably on level ground, with the
transmission in P (Park) for a few
minutes before turning the engine
off. If the overheat warning comes
on, see Engine Overheating 0302.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 11/9/16
272 Driving and Operating
Parking on Hills
{Warning
Parking the vehicle on a hill with
the trailer attached can be
dangerous. If something goes
wrong, the rig could start to move.
People can be injured, and both
the vehicle and the trailer can be
damaged. When possible, always
park the rig on a flat surface.
If parking the rig on a hill: 1. Press the brake pedal, but do not shift into P (Park) yet. Turn
the wheels into the curb if
facing downhill or into traffic if
facing uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the regular
brakes until the chocks absorb
the load.
4. Reapply the brake pedal. Then apply the parking brake and
shift into P (Park). 5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake
pedal.
2. Start the engine.
3. Shift into a gear.
4. Release the parking brake.
5. Let up on the brake pedal.
6. Drive slowly until the trailer is clear of the chocks.
7. Stop and have someone pick up and store the chocks.
Maintenance when Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule 0376.
Things that are especially important
in trailer operation are automatic
transmission fluid, engine oil, axle
lubricant, belts, cooling system, and
brake system. It is a good idea to
inspect these before and during
the trip. Check periodically to see that all
hitch nuts and bolts are tight.
Trailer Towing
Do not tow a trailer during break-in.
See
New Vehicle Break-In 0217.
Before towing a trailer, see
"Hands-Free Operation" under
Liftgate 044.
{Warning
The driver can lose control when
pulling a trailer if the correct
equipment is not used or the
vehicle is not driven properly. For
example, if the trailer is too heavy
or the trailer brakes are
inadequate for the load, the
vehicle may not stop as expected.
The driver and passengers could
be seriously injured. The vehicle
may also be damaged; the
resulting repairs would not be
covered by the vehicle warranty.
Pull a trailer only if all the steps in
this section have been followed.
(Continued)

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 11/9/16
Driving and Operating 273
Warning (Continued)
Ask your dealer for advice and
information about towing a trailer
with the vehicle.
Caution
Pulling a trailer improperly can
damage the vehicle and result in
costly repairs not covered by the
vehicle warranty. To pull a trailer
correctly, follow the advice in this
section and see your dealer for
important information about
towing a trailer with the vehicle.
To identify the trailering capacity of
the vehicle, read the information in
“Weight of the Trailer” following.
Trailering is different than just
driving the vehicle by itself.
Trailering means changes in
handling, acceleration, braking,
durability, and fuel economy. Successful, safe trailering takes
correct equipment, and it has to be
used properly.
The following information has many
time-tested, important trailering tips
and safety rules. Many of these are
important for your safety and that of
your passengers. So please read
this section carefully before pulling a
trailer.Weight of the Trailer
Safe trailering requires monitoring
the weight, speed, altitude, road
grades, outside temperature, and
how frequently the vehicle is used to
pull a trailer. Take into consideration
any special equipment on the
vehicle, and the amount of tongue
weight the vehicle can carry. See
“Weight of the Trailer Tongue”
later
in this section for more information. Trailer Weight Rating (TWR) is
calculated assuming the tow vehicle
has only the driver and all required
trailering equipment. Weight of
additional optional equipment,
passengers, and cargo in the tow
vehicle must be subtracted from the
trailer weight rating.
Use the following chart to determine
how much the vehicle can weigh,
based upon the vehicle model and
options.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-9955936) - 2017 - crc - 11/9/16
278 Driving and Operating
.When pulling a heavy trailer or a
large or heavy load in busy
parking lots where improved low
speed control of the vehicle is
desired.
Operating the vehicle in Tow/Haul
when lightly loaded or with no trailer
at all will not cause damage.
However, there is no benefit to the
selection of Tow/Haul when the
vehicle is unloaded. Such a
selection when unloaded may result
in unpleasant engine and
transmission driving characteristics
and reduced fuel economy. Tow/
Haul is recommended only when
pulling a heavy trailer or a large or
heavy load.
Integrated Trailer Brake
Control System
The vehicle may have an Integrated
Trailer Brake Control (ITBC) system
for use with electric trailer brakes or
most electric-over-hydraulic trailer
brakes.
This symbol is on the Trailer Brake
Control Panel on vehicles with an
ITBC system. The power output to
the trailer brakes is based on the
amount of brake pressure being
applied by the vehicle’s brake
system, and on the type of trailer
brakes detected. This available
power output to the trailer brakes
can be adjusted to a wide range of
trailering situations.
The ITBC system is integrated with
the vehicle’ s brake, antilock brake,
and StabiliTrak systems. In trailering
conditions that cause the vehicle’s
antilock brake or StabiliTrak
systems to activate, power sent to
the trailer's brakes will be
automatically adjusted to minimize
trailer wheel lock-up. This does not
imply that the trailer has StabiliTrak.
If the vehicle’s brake, antilock brake,
or StabiliTrak systems are not
functioning properly, the ITBC system may not be fully functional
or may not function at all. Make sure
all of these systems are fully
operational to ensure full
functionality of the ITBC system.
The ITBC system is powered
through the vehicle's electrical
system. Turning the ignition off will
also turn off the ITBC system. The
ITBC system is fully functional only
when the ignition is in ON/RUN.
{Warning
Connecting a trailer that has an
air brake system may result in
reduced or complete loss of trailer
braking. There may be an
increase in stopping distance or
trailer instability which could
result in personal injury or
damage to the vehicle, trailer,
or other property. Use the ITBC
system only with electric or
electric over hydraulic trailer
brakes.