GMC SIERRA DENALI 2015 Owners Manual

Black plate (2,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-2 Driving and Operating E85 or FlexFuel . . . . . . . . . . . . . . 9-65
Filling the Tank . . . . . . . . . . . . . . 9-66
Filling a Portable Fuel
Container . . . . . . . . . . . . . . . . . . . 9-67
Trailer Towing General Towing
Information . . . . . . . . . . . . . . . . . 9-68
Driving Characteristics and
Towing Tips . . . . . . . . . . . . . . . . 9-68
Trailer Towing . . . . . . . . . . . . . . . . 9-71
Towing Equipment . . . . . . . . . . . 9-78
Trailer Sway
Control (TSC) . . . . . . . . . . . . . . 9-87
Conversions and Add-Ons Add-On Electrical
Equipment . . . . . . . . . . . . . . . . . 9-88
Adding a Snow Plow or
Similar Equipment . . . . . . . . . . 9-88
Pickup Conversion to
Chassis Cab . . . . . . . . . . . . . . . 9-92 Driving Information Distracted Driving Distraction comes in many forms
and can take your focus from the
task of driving. Exercise good
judgment and do not let other
activities divert your attention away
from the road. Many local
governments have enacted laws
regarding driver distraction. Become
familiar with the local laws in
your area.
To avoid distracted driving, always
keep your eyes on the road, hands
on the wheel, and mind on the drive. .
Do not use a phone in
demanding driving situations.
Use a hands-free method to
place or receive necessary
phone calls. .
Watch the road. Do not read,
take notes, or look up
information on phones or other
electronic devices. .
Designate a front seat
passenger to handle potential
distractions. .
Become familiar with vehicle
features before driving, such as
programming favorite radio
stations and adjusting climate
control and seat settings.
Program all trip information into
any navigation device prior to
driving. .
Wait until the vehicle is parked
to retrieve items that have fallen
to the floor. .
Stop or park the vehicle to tend
to children. .
Keep pets in an appropriate
carrier or restraint. .
Avoid stressful conversations
while driving, whether with a
passenger or on a cell phone.

Black plate (3,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-3
{ WarningTaking your eyes off the road too
long or too often could cause a
crash resulting in injury or death.
Focus your attention on driving.
Refer to the infotainment section for
more information on using that
system and the navigation system,
if equipped, including pairing and
using a cell phone.
Defensive Driving Defensive driving means “ always
expect the unexpected. ” The first
step in driving defensively is to wear
the safety belt. See Safety Belts on
page 3-10 ..
Assume that other road users
(pedestrians, bicyclists, and
other drivers) are going to be
careless and make mistakes.
Anticipate what they might do
and be ready. .
Allow enough following distance
between you and the driver in
front of you. .
Focus on the task of driving.
Drunk Driving Death and injury associated with
drinking and driving is a global
tragedy.
{ WarningDrinking and then driving is very
dangerous. Your reflexes,
perceptions, attentiveness, and
judgment can be affected by even
a small amount of alcohol. You
can have a serious — or even
fatal — collision if you drive after
drinking.
Do not drink and drive or ride with
a driver who has been drinking.
Ride home in a cab; or if you are
with a group, designate a driver
who will not drink. Control of a Vehicle Braking, steering, and accelerating
are important factors in helping to
control a vehicle while driving.
Braking Braking action involves perception
time and reaction time. Deciding to
push the brake pedal is perception
time. Actually doing it is
reaction time.
Average driver reaction time is
about three-quarters of a second. In
that time, a vehicle moving at
100 km/h (60 mph) travels 20 m
(66 ft), which could be a lot of
distance in an emergency.
Helpful braking tips to keep in mind
include: .
Keep enough distance between
you and the vehicle in front
of you. .
Avoid needless heavy braking. .
Keep pace with traffic.

Black plate (4,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-4 Driving and Operating If the engine ever stops while the
vehicle is being driven, brake
normally but do not pump the
brakes. Doing so could make the
pedal harder to push down. If the
engine stops, there will be some
power brake assist but it will be
used when the brake is applied.
Once the power assist is used up, it
can take longer to stop and the
brake pedal will be harder to push.
Steering Electric Power Steering (1500
Series) If the vehicle has electric power
steering, it does not have power
steering fluid. Regular maintenance
is not required.
If power steering assist is lost due
to a system malfunction, the vehicle
can be steered, but may require
increased effort. See your dealer if
there is a problem. If the steering wheel is turned until it
reaches the end of its travel, and is
held in that position for an extended
period of time, power steering assist
may be reduced.
If the steering assist is used for an
extended period of time, power
assist may be reduced.
Normal use of the power steering
assist should return when the
system cools down.
See specific vehicle steering
messages under Steering System
Messages on page 5-38 .
Hydraulic Power Steering
(2500/3500 Series) If the vehicle has hydraulic power
steering, it may require
maintenance. See Power Steering
Fluid (1500 Series) on page 10-24
or Power Steering Fluid (2500/3500
Series) on page 10-24 . If power steering assist is lost
because the engine stops or a
system malfunctions, the vehicle
can be steered but may require
increased effort.
See your dealer if there is a
problem.
{ CautionIf the steering wheel is turned
until it reaches the end of its
travel, and is held in that position
for more than 15 seconds,
damage may occur to the power
steering system and there may be
loss of power steering assist.
Curve Tips .
Take curves at a reasonable
speed. .
Reduce speed before entering a
curve. .
Maintain a reasonable steady
speed through the curve.

Black plate (5,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-5.
Wait until the vehicle is out of
the curve before accelerating
gently into the straightaway.
Steering in Emergencies .
There are some situations when
steering around a problem may
be more effective than braking. .
Holding both sides of the
steering wheel allows you to turn
180 degrees without removing
a hand. .
Antilock Brake System (ABS)
allows steering while braking. Off-Road Recovery
The vehicle's right wheels can drop
off the edge of a road onto the
shoulder while driving. Follow
these tips:
1. Ease off the accelerator and
then, if there is nothing in the
way, steer the vehicle so that it
straddles the edge of the
pavement.
2. Turn the steering wheel about
one-eighth of a turn, until the
right front tire contacts the
pavement edge. 3. Turn the steering wheel to go
straight down the roadway.
Loss of Control Skidding There are three types of skids that
correspond to the vehicle's three
control systems: .
Braking Skid — wheels are not
rolling. .
Steering or Cornering Skid —
too much speed or steering in a
curve causes tires to slip and
lose cornering force. .
Acceleration Skid — too much
throttle causes the driving
wheels to spin.
Defensive drivers avoid most skids
by taking reasonable care suited to
existing conditions, and by not
overdriving those conditions. But
skids are always possible.

Black plate (6,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-6 Driving and Operating If the vehicle starts to slide, follow
these suggestions: .
Ease your foot off the
accelerator pedal and steer the
way you want the vehicle to go.
The vehicle may straighten out.
Be ready for a second skid if it
occurs. .
Slow down and adjust your
driving according to weather
conditions. Stopping distance
can be longer and vehicle
control can be affected when
traction is reduced by water,
snow, ice, gravel, or other
material on the road. Learn to
recognize warning clues — such
as enough water, ice, or packed
snow on the road to make a
mirrored surface — and slow
down when you have any doubt. .
Try to avoid sudden steering,
acceleration, or braking,
including reducing vehicle speed
by shifting to a lower gear. Any
sudden changes could cause
the tires to slide. Remember: Antilock brakes help
avoid only the braking skid.
Off-Road Driving Four-wheel-drive vehicles can be
used for off-road driving. Vehicles
without four-wheel drive and
vehicles not equipped with All
Terrain (AT) or On-Off Road (OOR)
tires must not be driven off-road
except on a level, solid surface. For
contact information about the
original equipment tires, see the
warranty manual.
One of the best ways for successful
off-road driving is to control the
speed.
{ Warning
When driving off-road, bouncing
and quick changes in direction
can easily throw you out of
position. This could cause you to
lose control and crash. You and
your passengers should always
wear safety belts. Before Driving Off-Road .
Have all necessary maintenance
and service work completed. .
Fuel the vehicle, fill fluid levels,
and check inflation pressure in
all tires, including the spare,
if equipped. .
Read all the information about
four-wheel-drive vehicles in this
manual. .
Remove any underbody air
deflector, if equipped. Re-attach
the air deflector after off-road
driving. .
See Hill Descent Control (HDC)
on page 9-51 .
Know the local laws that apply to
off-road driving.
To gain more ground clearance if
needed, it may be necessary to
remove the front fascia lower air
dam. However, driving without the
air dam reduces fuel economy.

Black plate (7,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-7
{ CautionOperating the vehicle for
extended periods without the front
fascia lower air dam installed can
cause improper air flow to the
engine. Re-attach the front fascia
air dam after off-road driving.
Loading the Vehicle for
Off-Road Driving
{ Warning .
Unsecured cargo on the load
floor can be tossed about
when driving over rough
terrain. You or your
passengers can be struck by
flying objects. Secure the
cargo properly.
(Continued) Warning (Continued) .
Keep cargo in the cargo area
as far forward and as low as
possible. The heaviest things
should be on the floor,
forward of the rear axle. .
Heavy loads on the roof raise
the vehicle's center of gravity,
making it more likely to roll
over. You can be seriously or
fatally injured if the vehicle
rolls over. Put heavy loads
inside the cargo area, not on
the roof.
For more information about loading
the vehicle, see Vehicle Load Limits
on page 9-15 and Tires on
page 10-50 .
Environmental Concerns .
Always use established trails,
roads, and areas that have been
set aside for public off-road
recreational driving and obey all
posted regulations. .
Do not damage shrubs, flowers,
trees, or grasses or disturb
wildlife. .
Do not park over things that
burn. See Parking over Things
That Burn on page 9-32 .
Driving on Hills Driving safely on hills requires good
judgment and an understanding of
what the vehicle can and cannot do.
{ WarningMany hills are simply too steep
for any vehicle. Driving up hills
can cause the vehicle to stall.
Driving down hills can cause loss
of control. Driving across hills can
cause a rollover. You could be
injured or killed. Do not drive on
steep hills.
Before driving on a hill, assess the
steepness, traction, and
obstructions. If the terrain ahead

Black plate (8,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-8 Driving and Operating cannot be seen, get out of the
vehicle and walk the hill before
driving further.
When driving on hills: .
Use a low gear and keep a firm
grip on the steering wheel. .
Maintain a slow speed. .
When possible, drive straight up
or down the hill. .
Slow down when approaching
the top of the hill. .
Use headlamps even during the
day to make the vehicle more
visible.
{ Warning
Driving to the top of a hill at high
speed can cause an accident.
There could be a drop-off,
embankment, cliff, or even
another vehicle. You could be
seriously injured or killed. As you
near the top of a hill, slow down
and stay alert. .
Never go downhill forward or
backward with either the
transmission or transfer case in
N (Neutral). The brakes could
overheat and you could lose
control.
{ WarningIf the vehicle has the two ‐ speed
automatic transfer case, shifting
the transfer case to N (Neutral)
can cause your vehicle to roll
even if the transmission is in
P (Park). This is because the
N (Neutral) position on the
transfer case overrides the
transmission. You or someone
else could be injured. If leaving
the vehicle, set the parking brake
and shift the transmission to
P (Park). Shift the transfer case to
any position but N (Neutral). .
When driving down a hill, keep
the vehicle headed straight
down. Use a low gear because
the engine will work with the brakes to slow the vehicle and
help keep the vehicle under
control.
{ WarningHeavy braking when going down
a hill can cause your brakes to
overheat and fade. This could
cause loss of control and you or
others could be injured or killed.
Apply the brakes lightly when
descending a hill and use a low
gear to keep vehicle speed under
control.
If the vehicle stalls on a hill:
1. Apply the brakes to stop the
vehicle, and then apply the
parking brake.

Black plate (9,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-92. Shift into P (Park) and then
restart the engine. .
If driving uphill when the
vehicle stalls, shift to
R (Reverse), release the
parking brake, and back
straight down. .
Never try to turn the vehicle
around. If the hill is steep
enough to stall the vehicle,
it is steep enough to cause
it to roll over. .
If you cannot make it up the
hill, back straight down
the hill. .
Never back down a hill in
N (Neutral) using only the
brake. The vehicle can roll
backward quickly and you
could lose control. .
If driving downhill when the
vehicle stalls, shift to a
lower gear, release the
parking brake, and drive
straight down the hill. 3. If the vehicle cannot be restarted
after stalling, set the parking
brake, shift into P (Park), and
turn the vehicle off.
3.1. Leave the vehicle and
seek help.
3.2. Stay clear of the path the
vehicle would take if it
rolled downhill. .
Avoid turns that take the vehicle
across the incline of the hill.
A hill that can be driven straight
up or down might be too steep to
drive across. Driving across an
incline puts more weight on the
downhill wheels, which could
cause a downhill slide or a
rollover. .
Surface conditions can be a
problem. Loose gravel, muddy
spots, or even wet grass can
cause the tires to slip sideways,
downhill. If the vehicle slips
sideways, it can hit something
that will trip it — a rock, a rut,
etc. — and roll over. .
Hidden obstacles can make the
steepness of the incline more
severe. If a rock is driven across
with the uphill wheels, or if the
downhill wheels drop into a rut
or depression, the vehicle can tilt
even more. .
If an incline must be driven
across, and the vehicle starts to
slide, turn downhill. This should
help straighten out the vehicle
and prevent the side slipping.
{ WarningGetting out of the vehicle on the
downhill side when stopped
across an incline is dangerous.
If the vehicle rolls over, you could
be crushed or killed. Always get
out on the uphill side of the
vehicle and stay well clear of the
rollover path.

Black plate (10,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-10 Driving and Operating Driving in Mud, Sand, Snow,
or Ice Use a low gear when driving in mud
— the deeper the mud, the lower
the gear. Keep the vehicle moving
to avoid getting stuck.
Traction changes when driving on
sand. On loose sand, such as on
beaches or sand dunes, the tires
tend to sink into the sand. This
affects steering, accelerating, and
braking. Drive at a reduced speed
and avoid sharp turns or abrupt
maneuvers.
Traction is reduced on hard packed
snow and ice and it is easy to lose
control. Reduce vehicle speed when
driving on hard packed snow
and ice.
{ Warning
Driving on frozen lakes, ponds,
or rivers can be dangerous. Ice
conditions vary greatly and the
(Continued) Warning (Continued) vehicle could fall through the ice;
you and your passengers could
drown. Drive your vehicle on safe
surfaces only.
Driving in Water
{ WarningDriving through rushing water can
be dangerous. Deep water can
sweep your vehicle downstream
and you and your passengers
could drown. If it is only shallow
water, it can still wash away the
ground from under your tires.
Traction could be lost, and the
vehicle could roll over. Do not
drive through rushing water. { CautionDo not drive through standing
water if it is deep enough to cover
the wheel hubs, axles, or exhaust
pipe. Deep water can damage the
axle and other vehicle parts.
If the standing water is not too deep,
drive slowly through it. At faster
speeds, water splashes and the
vehicle can stall. When going
through water, the brakes get wet
and it may take longer to stop. See
“ Driving on Wet Roads ” later in this
section.
After Off-Road Driving Remove any brush or debris that
has collected on the underbody or
chassis, or under the hood. These
accumulations can be a fire hazard.
After operation in mud or sand,
have the brake linings cleaned and
checked. These substances can
cause glazing and uneven braking.
Check the body structure, steering,

Black plate (11,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-11suspension, wheels, tires, and
exhaust system for damage and
check the fuel lines and cooling
system for any leakage.
More frequent maintenance service
is required. See the Maintenance
Schedule on page 11-3 .
Driving on Wet Roads Rain and wet roads can reduce
vehicle traction and affect your
ability to stop and accelerate.
Always drive slower in these types
of driving conditions and avoid
driving through large puddles and
deep ‐ standing or flowing water.
{ Warning
Wet brakes can cause crashes.
They might not work as well in a
quick stop and could cause
pulling to one side. You could
lose control of the vehicle.
(Continued) Warning (Continued) After driving through a large
puddle of water or a car/vehicle
wash, lightly apply the brake
pedal until the brakes work
normally.
Flowing or rushing water creates
strong forces. Driving through
flowing water could cause the
vehicle to be carried away. If this
happens, you and other vehicle
occupants could drown. Do not
ignore police warnings and be
very cautious about trying to drive
through flowing water.
Hydroplaning
Hydroplaning is dangerous. Water
can build up under the vehicle's
tires so they actually ride on the
water. This can happen if the road is
wet enough and you are going fast
enough. When the vehicle is
hydroplaning, it has little or no
contact with the road. There is no hard and fast rule about
hydroplaning. The best advice is to
slow down when the road is wet.
Other Rainy Weather Tips Besides slowing down, other wet
weather driving tips include: .
Allow extra following distance. .
Pass with caution. .
Keep windshield wiping
equipment in good shape. .
Keep the windshield washer fluid
reservoir filled. .
Have good tires with proper
tread depth. See Tires on
page 10-50 . .
Turn off cruise control.
Hill and Mountain Roads Driving on steep hills or through
mountains is different than driving
on flat or rolling terrain. Tips for
driving in these conditions include: .
Keep the vehicle serviced and in
good shape.