Black plate (1,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Lighting 6-1
Lighting Exterior Lighting Exterior Lamp Controls . . . . . . . . 6-1
Exterior Lamps Off
Reminder . . . . . . . . . . . . . . . . . . . . 6-2
Headlamp High/Low-Beam
Changer . . . . . . . . . . . . . . . . . . . . . 6-2
Flash-to-Pass . . . . . . . . . . . . . . . . . 6-2
Daytime Running
Lamps (DRL) . . . . . . . . . . . . . . . . 6-3
Automatic Headlamp
System . . . . . . . . . . . . . . . . . . . . . . 6-3
Hazard Warning Flashers . . . . . 6-4
Turn and Lane-Change
Signals . . . . . . . . . . . . . . . . . . . . . . 6-4
Fog Lamps . . . . . . . . . . . . . . . . . . . . 6-5
Auxiliary
Roof-Mounted Lamp . . . . . . . . . 6-5
Interior Lighting Instrument Panel Illumination
Control . . . . . . . . . . . . . . . . . . . . . . 6-6
Cargo Lamp . . . . . . . . . . . . . . . . . . 6-6
Dome Lamps . . . . . . . . . . . . . . . . . 6-7
Reading Lamps . . . . . . . . . . . . . . . 6-7 Lighting Features Entry Lighting . . . . . . . . . . . . . . . . . 6-8
Exit Lighting . . . . . . . . . . . . . . . . . . . 6-8
Battery Load Management . . . . 6-8
Battery Power Protection . . . . . . 6-9
Exterior Lighting Exterior Lamp Controls
The exterior lamp control is on the
instrument panel to the left of the
steering wheel.
O (Off): Turns off the automatic
headlamps and Daytime Running
Lamps (DRL). Turn the headlamp
control to the off position again to
turn the automatic headlamps or
DRL back on.
For vehicles first sold in Canada, off
will only work when the vehicle is in
P (Park).
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 (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 (15,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-15
{ 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.
There are recovery hooks at the
front of the vehicle. Use them if the
vehicle is stuck off-road and needs
to be pulled some place to continue
driving. Vehicle Load Limits It is very important to know how
much weight the vehicle can
carry. This weight is called the
vehicle capacity weight and
includes the weight of all
occupants, cargo, and all
nonfactory-installed options.
Two labels on the vehicle show
how much weight it was
designed to carry: the Tire and
Loading Information label and
the Certification/Tire label.
{ Warning
Do not load the vehicle any
heavier than the Gross
Vehicle Weight Rating
(GVWR), or either the
maximum front or rear Gross
Axle Weight Rating (GAWR).
This can cause systems to
break and change the way the
(Continued) Warning (Continued)
vehicle handles. This could
cause loss of control and a
crash. Overloading can also
shorten the life of the vehicle. Tire and Loading Information
Label
Label Example
A vehicle-specific Tire and
Loading Information label is
attached to the center pillar
(B-pillar). With the driver door
Black plate (26,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-26 Driving and Operating 4 (START): This is the position that
starts the engine. When the engine
starts, release the key. The ignition
switch returns to ON/RUN for
driving.
A warning tone will sound when the
driver door is opened and the
ignition is in ACC/ACCESSORY or
LOCK/OFF, and the key is in the
ignition.
Starting the Engine If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
{ Caution
If you add electrical parts or
accessories, you could change
the way the engine operates. Any
resulting damage would not be
covered by the vehicle warranty.
See Add-On Electrical Equipment
on page 9-88 . { CautionIf the steering wheel is turned
until it reaches the end of its
travel, and is held in that position
while starting the vehicle, damage
may occur to the hydraulic power
steering system and there may be
loss of power steering assist.
Move the shift lever to P (Park) or
N (Neutral). To restart the engine
when the vehicle is already moving,
use N (Neutral) only.
{ Caution
Do not try to shift to P (Park) if the
vehicle is moving. If you do, you
could damage the transmission.
Shift to P (Park) only when the
vehicle is stopped. Starting Procedure 1. Turn the ignition key to START.
When the engine starts, let go of
the key. The idle speed will go
down as the engine gets warm.
Do not race the engine
immediately after starting it.
Operate the engine and
transmission gently to allow the
oil to warm up and lubricate all
moving parts.
When the low fuel warning light
is on and the FUEL LEVEL LOW
message is displayed in the
Driver Information Center (DIC),
hold the ignition switch in the
START position to continue
engine cranking.
{ Caution
Cranking the engine for long
periods of time, by returning the
ignition to the START position
immediately after cranking has
ended, can overheat and damage
(Continued)
Black plate (39,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-39Low Traction Mode If equipped, Low Traction Mode
assists in vehicle acceleration when
road conditions are slippery, such
as with ice or snow. While the
vehicle is at a stop, select M2 using
Range Selection Mode. This will
limit torque to the wheels and help
to prevent the tires from spinning.
Tow/Haul Mode
The vehicle has a Tow/Haul Mode.
The Tow/Haul Mode adjusts the
transmission shift pattern to reduce shift cycling, providing increased
performance, vehicle control, and
enhanced transmission and engine
cooling when driving down steep
hills or mountain grades, towing,
or hauling heavy loads.
The selector button is on the end of
the shift lever. Turn the Tow/Haul
Mode on and off by pressing the
button. When the Tow/Haul Mode is
enabled, a light on the instrument
cluster will come on.
See Tow/Haul Mode Light on
page 5-22 and Hill and Mountain
Roads on page 9-11 .
Also see “ Tow/Haul Mode ” under
Towing Equipment on page 9-78 .
Tow/Haul Mode Grade Braking
Tow/Haul Mode Grade Braking is
only enabled while the Tow/Haul
Mode is selected and the vehicle is
not in the Range Selection Mode.
See “ Tow/Haul Mode ” listed
previously and Manual Mode on
page 9-36 . Tow/Haul Mode Grade
Braking assists in maintaining desired vehicle speeds when driving
on downhill grades by using the
engine and transmission to slow the
vehicle.
On vehicles with a gasoline engine,
to disable or enable Tow/Haul
Grade Braking within the current
ignition key cycle, press and hold
the Tow/Haul button for
five seconds. When the button is
released, the requested mode
change is made. A DIC message is
displayed. See Transmission
Messages on page 5-39 .
On vehicles with a diesel engine,
Tow/Haul Mode Grade Braking can
be enabled or disabled by pressing
the Tow/Haul Mode button. Use the
exhaust brake and Tow/Haul Mode
for maximum grade braking.
See Towing Equipment on
page 9-78 .
For other forms of grade braking,
see Automatic Transmission on
page 9-33 and Cruise Control on
page 9-52 .
Black plate (47,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-47If driving safely on a wet road and it
becomes necessary to slam on the
brakes and continue braking to
avoid a sudden obstacle, a
computer senses the wheels are
slowing down. If one of the wheels
is about to stop rolling, the computer
will separately work the brakes at
each wheel.
ABS can change the brake pressure
to each wheel, as required, faster
than any driver could. This can help
you steer around the obstacle while
braking hard.
As the brakes are applied, the
computer keeps receiving updates
on wheel speed and controls
braking pressure accordingly.
Remember: ABS does not change
the time needed to get a foot up to
the brake pedal or always decrease
stopping distance. If you get too
close to the vehicle in front of you,
there will not be enough time to
apply the brakes if that vehicle suddenly slows or stops. Always
leave enough room up ahead to
stop, even with ABS.
Using ABS Do not pump the brakes. Just hold
the brake pedal down firmly and let
ABS work. You may hear the ABS
pump or motor operating and feel
the brake pedal pulsate. This is
normal.
Braking in Emergencies ABS allows you to steer and brake
at the same time. In many
emergencies, steering can help
more than even the very best
braking. Parking Brake
Set the parking brake by holding the
regular brake pedal down, then
pushing down the parking brake
pedal.
If the ignition is on, the brake
system warning light will come on.
See Brake System Warning Light on
page 5-21 .
Black plate (52,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-52 Driving and Operating HDC will remain enabled between
22 and 60 km/h (14 and 37 mph);
however vehicle speed cannot be
set or maintained in this range.
It will automatically disable if the
vehicle speed is above 80 km/h
(50 mph) or above 60 km/h
(37 mph) for at least
30 seconds.
5 must be pressed
again to re-enable HDC.
When enabled, if the vehicle is at a
speed above 22 km/h (14 mph) and
less than 60 km/h (37 mph), a DIC
message will display. See Vehicle
Speed Messages on page 5-42 .
Locking Rear Axle Vehicles with a locking rear axle can
give more traction on snow, mud,
ice, sand, or gravel. It works like a
standard axle most of the time, but
when traction is low, this feature will
allow the rear wheel with the most
traction to move the vehicle. Cruise Control With cruise control a speed of about
40 km/h (25 mph) or more can be
maintained without keeping your
foot on the accelerator. Cruise
control does not work at speeds
below about 40 km/h (25 mph).
{ WarningCruise control can be dangerous
where you cannot drive safely at
a steady speed. Do not use
cruise control on winding roads or
in heavy traffic.
Cruise control can be dangerous
on slippery roads. On such roads,
fast changes in tire traction can
cause excessive wheel slip, and
you could lose control. Do not use
cruise control on slippery roads. If equipped with an Allison or
Hydra-Matic 6-speed automatic
transmission, see “ Tow/Haul Mode
Grade Braking ” under Tow/Haul
Mode on page 9-39 for an
explanation of how cruise control
interacts with the Range Selection
Mode, Tow/Haul Mode, and Grade
Braking systems.
If the cruise control is being used
and the Traction Control System
(TCS) or StabiliTrak begins to limit
wheel spin, the cruise control will
automatically disengage. See
Traction Control/Electronic Stability
Control on page 9-49 . If a collision
alert occurs when cruise control is
activated, cruise control is
disengaged. See Forward Collision
Alert (FCA) System on page 9-59 .
When road conditions allow you to
safely use it again, cruise control
can be turned back on.
If the brakes are applied, the cruise
control disengages.