
Black plate (5,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Lighting 6-5one second will cause the turn
signals to flash until the lever is
released.
The lever returns to its starting
position whenever it is released.
If after signaling a turn or a lane
change the arrows flash rapidly or
do not come on, a signal bulb could
be burned out.
Replace any burned out bulbs. If a
bulb is not burned out, check the
fuse. See Fuses on page 10-41 .
Turn Signal On Chime
If the turn signal is left on for more
than 1.2 km (0.75 mi), a chime
sounds at each flash of the turn
signal. The message TURN
SIGNAL ON will also appear in the
Driver Information Center (DIC). To
turn the chime and message off,
move the turn signal lever to the off
position. Fog Lamps
The fog lamp control is on the
center of the exterior lamp control,
to the left of the steering column.
The ignition must be on for the fog
lamps to come on.
# (Fog Lamps): Press to turn the
fog lamps on or off. A light will come
on in the instrument cluster.
When the fog lamps are turned on,
the parking lamps automatically
turn on. When the headlamps are changed
to high beam, the fog lamps also go
off. When the high-beam headlamps
are turned off, the fog lamps will
come on again.
Some localities have laws that
require the headlamps to be on with
the fog lamps.
Auxiliary
Roof-Mounted Lamp If equipped, this button includes
wiring provisions for a dealer or a
qualified service center to install an
auxiliary roof lamp.
This button is on the overhead
console.

Black plate (7,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Lighting 6-7mirrors turn on if the shift lever is in
the R (Reverse), N (Neutral),
or P (Park) position.
Dome Lamps
There are dome lamps in the
overhead console and the headliner,
if equipped.
To change the dome lamp settings,
press the following:
OFF: Turns the lamps off, even
when a door is open. DOOR: The lamps come on
automatically when a door is
opened.
ON: Turns all dome lamps on.
Reading Lamps
There are reading lamps in the
overhead console and the headliner,
if equipped. To operate, the ignition
must be in the ACC/ACCESSORY
or ON/RUN position, or using
Retained Accessory Power (RAP). Press
m or
n next to each reading
lamp to turn it on or off.

Black plate (8,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
6-8 Lighting
Lighting Features Entry Lighting The vehicle has an illuminated entry
feature.
When a door is opened, the dome
lamps and puddle lamps come on if
the dome lamp control is in the
DOOR position. If the dome lamp
control is in the OFF position, the
lamps do not come on.
The headlamps, parking lamps,
taillamps, and back-up lamps turn
on briefly at night, or in areas with
limited lighting, when
K is pressed
on the Remote Keyless Entry (RKE)
transmitter. After about 30 seconds
the exterior lamps turn off. Entry
lighting can be disabled manually by
changing the ignition out of the OFF
position, or by pressing the RKE
transmitter
Q button.
This feature can be changed. See
“ Vehicle Locator Lights ” under
Vehicle Personalization on
page 5-42 . Exit Lighting The interior lamps, headlamps,
parking lamps, back-up lamps, and
license plate lamps come on when
the key is removed from the ignition.
The interior lamps turn off
automatically in 20 seconds. The
interior lamps do not come on if the
dome lamp control is in the OFF
position.
The exterior lamps turn off
immediately by turning the exterior
lamps control off.
This feature can be changed. See
Vehicle Personalization on
page 5-42 .
Battery Load
Management The vehicle has Electric Power
Management (EPM), which
estimates the battery's temperature
and state of charge. It then adjusts
the voltage for best performance
and extended life of the battery. When the battery's state of charge
is low, the voltage is raised slightly
to quickly bring the charge back up.
When the state of charge is high,
the voltage is lowered slightly to
prevent overcharging. The voltmeter
gauge or the voltage display on the
Driver Information Center (DIC),
if equipped, may show the voltage
moving up or down. This is normal.
If there is a problem, an alert will be
displayed.
The battery can be discharged at
idle if the electrical loads are very
high. This is true for all vehicles.
This is because the generator
(alternator) may not be spinning fast
enough at idle to produce all the
power that is needed for very high
electrical loads.
A high electrical load occurs when
several of the following are on, such
as: headlamps, high beams, fog
lamps, rear window defogger,
climate control fan at high speed,
heated seats, engine cooling fans,
trailer loads, and loads plugged into
accessory power outlets.

Black plate (9,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Lighting 6-9EPM works to prevent excessive
discharge of the battery. It does this
by balancing the generator's output
and the vehicle's electrical needs.
It can increase engine idle speed to
generate more power, whenever
needed. It can temporarily reduce
the power demands of some
accessories.
Normally, these actions occur in
steps or levels, without being
noticeable. In rare cases at the
highest levels of corrective action,
this action may be noticeable to the
driver. If so, a DIC message might
be displayed and it is recommended
that the driver reduce the electrical
loads as much as possible. See
Battery Voltage and Charging
Messages on page 5-31 . Battery Power Protection This feature shuts off the dome and
reading lamps, if they are left on for
more than 10 minutes after the
ignition is turned off. The cargo
lamp shuts off after 20 minutes. This
prevents the battery from
running down.

Black plate (3,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Climate Controls 8-3Changing the mode cancels the
automatic operation and the system
goes into manual mode. Press
AUTO to return to automatic
operation.
Y (Vent): Air is directed to the
instrument panel outlets.
\ (Bi-Level): Air is divided
between the instrument panel and
floor outlets. Some air is directed
toward the windshield and side
window outlets.
[ (Floor): Air is directed to the
floor outlets, with some to the
windshield, side window outlets, and
second row floor outlets.
- (Defog): This mode clears the
windows of fog or moisture. Air is
directed to the windshield, floor
outlets, and side window vents. The
system automatically forces outside
air into the vehicle and the air
conditioning compressor will run,
unless the outside temperature is
close to freezing. 0 (Defrost): Press to clear the
windshield of fog or frost more
quickly. Air is directed to the
windshield and the side window
vents. The air conditioning
compressor also comes on, unless
the outside temperature is below
freezing.
Do not drive the vehicle until all
windows are clear.
See Air Vents on page 8-4 .
A/C (Air Conditioning): Press to
turn the air conditioning system on
or off. An indicator light comes on to
show that the air conditioning is
enabled. If the fan is turned off, the
air conditioner will not run. The A/C
light will stay on even if the outside
temperatures are below freezing.
@ (Recirculation): Press to turn
on recirculation. An indicator light
comes on. Air is recirculated to
quickly cool the inside of the
vehicle. It can also be used to help
reduce outside air and odors that enter the vehicle. The air
conditioning compressor also comes
on when this mode is activated.
Rear Window Defogger The rear window defogger uses a
warming grid to remove fog from the
rear window.
K (Rear Window Defogger):
Press to turn the rear window
defogger on or off. An indicator light
on the button comes on to show that
the rear window defogger is on.
The rear window defogger only
works when the ignition is in ON/
RUN. The defogger turns off if the
ignition is turned to ACC/
ACCESSORY or LOCK/OFF.
{ Caution
Using a razor blade or sharp
object to clear the inside rear
window can damage the rear
window defogger. Repairs would
(Continued)

Black plate (1,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-1
Driving and
Operating Driving Information Distracted Driving . . . . . . . . . . . . . 9-2
Defensive Driving . . . . . . . . . . . . . 9-3
Drunk Driving . . . . . . . . . . . . . . . . . 9-3
Control of a Vehicle . . . . . . . . . . . 9-3
Braking . . . . . . . . . . . . . . . . . . . . . . . 9-3
Steering . . . . . . . . . . . . . . . . . . . . . . . 9-4
Off-Road Recovery . . . . . . . . . . . . 9-5
Loss of Control . . . . . . . . . . . . . . . . 9-5
Off-Road Driving . . . . . . . . . . . . . . 9-6
Driving on Wet Roads . . . . . . . . 9-11
Hill and Mountain Roads . . . . . 9-11
Winter Driving . . . . . . . . . . . . . . . 9-12
If the Vehicle Is Stuck . . . . . . . . 9-14
Vehicle Load Limits . . . . . . . . . . 9-15
Truck-Camper Loading
Information . . . . . . . . . . . . . . . . . 9-21
Starting and Operating New Vehicle Break-In . . . . . . . . 9-23
Adjustable Throttle and Brake
Pedal . . . . . . . . . . . . . . . . . . . . . . . 9-23
Ignition Positions . . . . . . . . . . . . 9-24
Starting the Engine . . . . . . . . . . 9-26 Fast Idle System . . . . . . . . . . . . . 9-27
Engine Heater . . . . . . . . . . . . . . . 9-28
Retained Accessory
Power (RAP) . . . . . . . . . . . . . . . 9-29
Shifting Into Park . . . . . . . . . . . . 9-30
Shifting out of Park . . . . . . . . . . 9-31
Parking over Things
That Burn . . . . . . . . . . . . . . . . . . 9-32
Active Fuel Management ®
. . . 9-32
Engine Exhaust Engine Exhaust . . . . . . . . . . . . . . 9-32
Running the Vehicle While
Parked . . . . . . . . . . . . . . . . . . . . . 9-33
Automatic Transmission Automatic Transmission . . . . . 9-33
Manual Mode . . . . . . . . . . . . . . . . 9-36
Tow/Haul Mode . . . . . . . . . . . . . . 9-39
Drive Systems Four-Wheel Drive . . . . . . . . . . . . 9-40
Brakes Antilock Brake
System (ABS) . . . . . . . . . . . . . . 9-46
Parking Brake . . . . . . . . . . . . . . . 9-47
Brake Assist . . . . . . . . . . . . . . . . . 9-48
Hill Start Assist (HSA) . . . . . . . 9-48 Ride Control Systems Traction Control/Electronic
Stability Control . . . . . . . . . . . . 9-49
Hill Descent
Control (HDC) . . . . . . . . . . . . . . 9-51
Locking Rear Axle . . . . . . . . . . . 9-52
Cruise Control Cruise Control . . . . . . . . . . . . . . . 9-52
Driver Assistance Systems Driver Assistance
Systems . . . . . . . . . . . . . . . . . . . . 9-55
Assistance Systems for
Parking or Backing . . . . . . . . . 9-56
Assistance Systems for
Driving . . . . . . . . . . . . . . . . . . . . . 9-59
Forward Collision Alert (FCA)
System . . . . . . . . . . . . . . . . . . . . . 9-59
Lane Departure
Warning (LDW) . . . . . . . . . . . . . 9-61
Fuel Fuel . . . . . . . . . . . . . . . . . . . . . . . . . 9-63
California Fuel
Requirements . . . . . . . . . . . . . . 9-64
Fuels in Foreign Countries . . . 9-64
Fuel Additives . . . . . . . . . . . . . . . 9-64

Black plate (12,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-12 Driving and Operating .
Check all fluid levels and brakes,
tires, cooling system, and
transmission. .
Shift to a lower gear when going
down steep or long hills.
{ WarningUsing the brakes to slow the
vehicle on a long downhill slope
can cause brake overheating, can
reduce brake performance, and
could result in a loss of braking.
Shift the transmission to a lower
gear to let the engine assist the
brakes on a steep downhill slope.
{ Warning
Coasting downhill in N (Neutral)
or with the ignition off is
dangerous. This can cause
overheating of the brakes and
(Continued) Warning (Continued) loss of steering. Always have the
engine running and the vehicle
in gear. .
Stay in your own lane. Do not
swing wide or cut across the
center of the road. Drive at
speeds that let you stay in your
own lane. .
Be alert on top of hills;
something could be in your lane
(stalled car, accident). .
Pay attention to special road
signs (falling rocks area, winding
roads, long grades, passing or
no-passing zones) and take
appropriate action.
Winter Driving Driving on Snow or Ice
Drive carefully when there is snow
or ice between the tires and the
road, creating less traction or grip. Wet ice can occur at about 0°C
(32°F) when freezing rain begins to
fall, resulting in even less traction.
Avoid driving on wet ice or in
freezing rain until roads can be
treated with salt or sand.
Drive with caution, whatever the
condition. Accelerate gently so
traction is not lost. Accelerating too
quickly causes the wheels to spin
and makes the surface under the
tires slick, so there is even less
traction.
Traction Control should be turned
on. See Traction Control/Electronic
Stability Control on page 9-49 .
The Antilock Brake System (ABS)
improves vehicle stability during
hard stops on slippery roads, but
apply the brakes sooner than when
on dry pavement. See Antilock
Brake System (ABS) on page 9-46 .
Allow greater following distance on
any slippery road and watch for
slippery spots. Icy patches can
occur on otherwise clear roads in
shaded areas. The surface of a

Black plate (24,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-24 Driving and Operating No adjustment to the pedals can be
made when the vehicle is in
R (Reverse) or while using cruise
control.
The switch used to adjust the
pedals is on the center stack, below
the climate controls.
Lift the switch up to move the
pedals closer to your body. Press
the switch down to move the
pedals away. Before you start driving, fully press
the brake pedal to confirm the
adjustment is right for you. While
driving, make only small
adjustments.
The vehicle may have a memory
function, which lets pedal settings
be saved and recalled. See Memory
Seats on page 3-5 .
Ignition Positions
Vehicles with Key Access have an
ignition switch with four different
positions. To shift out of P (Park), the ignition
must be in ON/RUN or ACC/
ACCESSORY and the regular brake
pedal must be applied.
1 (STOPPING THE ENGINE/LOCK/
OFF): When the vehicle is stopped,
turn the ignition switch to LOCK/
OFF to turn the engine off. Retained
Accessory Power (RAP) will remain
active. See Retained Accessory
Power (RAP) on page 9-29 .
This position locks the ignition and
steering wheel. It also locks the
transmission on automatic
transmission vehicles. The key can
be removed in LOCK/OFF.
The steering can bind with the
wheels turned off center. If this
happens, move the steering wheel
from right to left while turning the
key to ACC/ACCESSORY. If this
does not work, then the vehicle
needs service.