
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Climate Controls 247
1. Driver Temperature Control
2. A/C (Air Conditioning)
3. Air Delivery Mode Controls
4. Fan Control
5. Defrost
6. Passenger TemperatureControl
7. SYNC (Synchronized Temperature)
8. Rear Window Defogger
9. Power Button
10. Air Recirculation
11. AUTO (Automatic Operation) Automatic Operation
The system automatically controls
the fan speed, air delivery, air
conditioning, and recirculation in
order to heat or cool the vehicle to
the desired temperature.
When the indicator light is on, the
system is in full automatic operation.
If the air delivery mode or fan
setting is manually adjusted, the
auto indicator turns off and displays
will show the selected settings.To place the system in
automatic mode:
1. Press AUTO.
2. Set the driver and passenger temperature.
To find your comfort setting,
start with 22 °C (72 °F) and
allow the system time to
stabilize. Then adjust the
temperature as needed for best
comfort.
To improve fuel efficiency and to
cool the vehicle faster, recirculation
may be automatically selected in
warm weather.
The recirculation light will not come
on when automatically controlled.
Press
@to manually select
recirculation; press it again to select
outside air.
Do not cover the solar sensor on the
top of the instrument panel near the
windshield. This sensor regulates
air temperature based on sun load.
See “Sensors” later in this section.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
264 Driving and Operating
Warning (Continued)
.Clear snow from the base of
the vehicle, especially any
blocking the exhaust pipe.
. Open a window about 5 cm
(2 in) on the vehicle side
that is away from the wind,
to bring in fresh air.
. Fully open the air outlets on
or under the instrument
panel.
. Adjust the climate control
system to circulate the air
inside the vehicle and set
the fan speed to the highest
setting. See “Climate
Control Systems.”
For more information about CO,
see Engine Exhaust 0282.
To save fuel, run the engine for
short periods to warm the vehicle
and then shut the engine off and
partially close the window. Moving
about to keep warm also helps. If it takes time for help to arrive,
when running the engine, push the
accelerator pedal slightly so the
engine runs faster than the idle
speed. This keeps the battery
charged to restart the vehicle and to
signal for help with the headlamps.
Do this as little as possible, to
save fuel.
If the Vehicle Is Stuck
Slowly and cautiously spin the
wheels to free the vehicle when
stuck in sand, mud, ice, or snow.
See
“Rocking the Vehicle to Get It
Out” later in this section.
The Traction Control System (TCS)
can often help to free a stuck
vehicle. See Traction Control/
Electronic Stability Control 0299.
If TCS cannot free the vehicle, see
“Rocking the Vehicle to Get it Out”
following.
{Warning
If the vehicle's tires spin at high
speed, they can explode, and you
or others could be injured. The
vehicle can overheat, causing an
engine compartment fire or other
damage. Spin the wheels as little
as possible and avoid going
above 56 km/h (35 mph).
For information about using tire
chains on the vehicle, see Tire
Chains 0422.
Rocking the Vehicle to Get
It Out
Turn the steering wheel left and
right to clear the area around the
front wheels. For four-wheel-drive
vehicles, shift into Four-Wheel Drive
High. Turn the TCS off. Shift back
and forth between R (Reverse) and
a forward gear, spinning the wheels
as little as possible. To prevent
transmission wear, wait until the
wheels stop spinning before shifting
gears. Slowly spinning the wheels in
the forward and reverse directions

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Driving and Operating 273
Starting and
Operating
New Vehicle Break-In
Caution
The vehicle does not need an
elaborate break-in. But it will
perform better in the long run if
you follow these guidelines:. Keep the vehicle speed at
88 km/h (55 mph) or less for
the first 805 km (500 mi).
. Do not drive at any one
constant speed, fast or slow,
for the first 805 km (500 mi).
Do not make full-throttle
starts. Avoid downshifting to
brake or slow the vehicle.
. Avoid making hard stops for
the first 322 km (200 mi) or
so. During this time the new
brake linings are not yet
broken in. Hard stops with
new linings can mean
(Continued)
Caution (Continued)
premature wear and earlier
replacement. Follow this
breaking-in guideline every
time you get new brake
linings.
. Do not tow a trailer during
break-in. See Trailer Towing
0 323 for the trailer towing
capabilities of the vehicle
and more information.
Following break-in, engine speed
and load can be gradually
increased.
Adjustable Throttle and
Brake Pedal
If equipped, the position of the
throttle and brake pedals can be
changed.
The pedals can only be adjusted
when the vehicle is in P (Park).
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.
The vehicle may have a memory
function, which lets pedal settings
be saved and recalled. See Memory
Seats 060.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
276 Driving and Operating
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
the cranking motor, and drain the
battery. Wait at least 15 seconds
between each try, to let the
cranking motor cool down.
2. If the engine does not start after five to 10 seconds,
especially in very cold weather
(below −18 °C or 0 °F), it could
be flooded with too much
gasoline. Try pushing the
accelerator pedal all the way to
the floor and holding it there
while holding the key in START
for up to 15 seconds. Wait at
least 15 seconds between each
try, to allow the cranking motor
to cool down. When the engine
starts, let go of the key and
accelerator. If the vehicle starts
briefly but then stops again, do
the same thing. This clears the extra gasoline from the engine.
Do not race the engine
immediately after starting it.
Operate the engine and
transmission gently until the oil
warms up and lubricates all
moving parts.
Fast Idle System
If equipped, this feature is available
only with cruise control. The manual
fast idle switch is operated using the
cruise control buttons on the left
side of the steering wheel.
This system can be used to
increase engine idle speed
whenever the following conditions
are met:
.
The parking brake is set.
. The brake pedal is not pressed.
. The vehicle must not be moving
and the accelerator must not be
pressed.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Driving and Operating 277
To control the fast idle:
.To enable the Fast Idle System,
press and release the cruise
control on/off button and ensure
that the switch indicator light
is lit.
. Press and release the cruise
control SET- button. Engine
speed will be held at
approximately 1200 rpm.
One of the following actions will turn
off the fast idle:
. Pressing the brake.
. Selecting the cruise control
cancel button.
. Releasing the parking brake.
. Moving the transmission shift
lever out of P (Park) or
N (Neutral).
. Selecting the cruise control on/
off button when it was
previously on.
. Pressing the cruise control SET-
button a second time. .
Pressing the accelerator more
than one-quarter of the
way down.
. Turning the ignition off.
Retained Accessory
Power (RAP)
The following vehicle accessories
can be used for up to 10 minutes
after the engine is turned off:
.Audio System
. Power Windows
. OnStar System (if equipped)
. Sunroof (if equipped)
These features work when the key
is in ON/RUN or ACC/
ACCESSORY. Once the key is
turned from ON/RUN to LOCK/OFF,
the windows and sunroof continue
to work up to 10 minutes or until any
door is opened. The radio continues
to work for up to 10 minutes or until
the driver door is opened. Accessory Power Outlets (APOs)
The vehicle may have Accessory
Power Outlets (APOs) in several
locations. See
Power Outlets0128.
The APOs in the console or center
seat position are powered by
Retained Accessory Power (RAP).
They will continue to work for up to
10 minutes after the key is turned
from ON/RUN to LOCK/OFF, or until
the driver door is opened.
The APOs on the center stack come
from the factory powered directly
from the vehicle battery, and supply
accessory power at all times,
regardless of ignition key position.
If electronic items are left plugged
into these APOs for long periods of
time with the vehicle off, the vehicle
battery could be drained. The
vehicle may not start if the battery is
allowed to drain for an extended
period of time.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Driving and Operating 279
Warning (Continued)
it overheat and cause a fire,
property damage, electric
shock, and injury.
. Do not operate the vehicle
with the heater cord
permanently attached to the
vehicle. Possible heater
cord and thermostat
damage could occur.
. While in use, do not let the
heater cord touch vehicle
parts or sharp edges. Never
close the hood on the
heater cord.
. Before starting the vehicle,
unplug the cord, reattach
the cover to the plug, and
securely fasten the cord.
Keep the cord away from
any moving parts. 4. Before starting the engine, be
sure to unplug and store the
cord as it was before to keep it
away from moving engine
parts. If you do not, it could be
damaged.
The length of time the heater should
remain plugged in depends on
several factors. Ask a dealer in the
area where you will be parking the
vehicle for the best advice on this.
Shifting Into Park
{Warning
It can be dangerous to get out of
the vehicle if the shift lever is not
fully in P (Park) with the parking
brake firmly set. The vehicle can
roll. If you have left the engine
running, the vehicle can move
suddenly. You or others could be
injured. To be sure the vehicle will
not move, even when you are on
fairly level ground, use the steps
that follow. With four-wheel drive,
if the transfer case is in (Continued)
Warning (Continued)
N (Neutral), the vehicle will be
free to roll, even if the shift lever
is in P (Park). Be sure the transfer
case is in a drive gear. If towing a
trailer, seeDriving Characteristics
and Towing Tips 0320.
1. Hold the brake pedal down, then set the parking brake.
See Parking Brake 0297.
2. Move the shift lever into the P (Park) position by pulling the
shift lever toward you and
moving it up as far as it will go.
3. Be sure the transfer case (if equipped) is in a drive
gear —not in N (Neutral).
4. Turn the ignition key to LOCK/OFF.
5. Remove the key and take it with you. If you can leave the
vehicle with the ignition key in
your hand, the vehicle is in
P (Park).

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Driving and Operating 285
The transmission uses adaptive
shift controls. The adaptive shift
control process continually
compares key shift parameters to
pre-programmed ideal shifts stored
in the transmission’s computer. The
transmission constantly makes
adjustments to improve vehicle
performance according to how the
vehicle is being used, such as with
a heavy load or when the
temperature changes. During this
adaptive shift control process,
shifting might feel different as the
transmission determines the best
settings.
When temperatures are very cold,
the transmission's gear shifting
could be delayed providing more
stable shifts until the engine warms
up. Shifts could be more noticeable
with a cold transmission. This
difference in shifting is normal.
L :This position allows selection of
a range of gears appropriate for
current driving conditions.
If equipped, see “Range Selection
Mode” underManual Mode 0286.Caution
Spinning the tires or holding the
vehicle in one place on a hill
using only the accelerator pedal
may damage the transmission.
The repair will not be covered by
the vehicle warranty. If the vehicle
is stuck, do not spin the tires.
When stopping on a hill, use the
brakes to hold the vehicle in
place.
Normal Mode Grade Braking
If equipped with a gasoline engine
and an automatic transmission,
Normal Mode Grade Braking is
enabled when the vehicle is started,
but is not enabled in Range
Selection Mode. It assists in
maintaining desired vehicle speeds
when driving on downhill grades by
using the engine and transmission
to slow the vehicle. The first time
the system engages for each
ignition key cycle, a DIC message
will be displayed. See Transmission
Messages 0164. To disable or enable Normal Mode
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
displays. See
Transmission
Messages 0164.
For other forms of grade braking,
see Tow/Haul Mode 0288 and
Cruise Control 0302.
Kickdown Mode
If equipped, the accelerator pedal
provides an additional downshift
after pressing through the kickdown
feature.
It requires extra pedal pressure near
the end of its travel to engage.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/19/17
Driving and Operating 289
Drive Systems
Four-Wheel Drive
If equipped, four-wheel drive
engages the front axle for extra
traction. Read the appropriate
section for transfer case operation
before using.
Caution
Do not drive on clean, dry
pavement in 4
mand 4n(if
equipped) for an extended period
of time. These conditions may
cause premature wear on the
vehicle’s powertrain.
Driving on clean, dry pavement in
4
mor 4nmay:
. Cause a vibration to be felt in
the steering system.
. Cause tires to wear faster.
. Make the transfer case harder to
shift, and cause it to run noisier.
{Warning
Shifting the transfer case to
N (Neutral) can cause the vehicle
to roll even if the transmission is
in P (Park). You or someone else
could be seriously injured. Be
sure to set the parking brake
before placing the transfer case in
N (Neutral). See Parking Brake
0 297.
Caution
Extended high-speed operation in
4
nmay damage or shorten the
life of the drivetrain.
Engagement noise and bump when
shifting between 4
nand 4mor from
N (Neutral), with the engine running,
is normal.
Shifting into 4
nwill turn Traction
Control and StabiliTrak®off. See
Traction Control/Electronic Stability
Control 0299.
Manual Transfer Case
Move the lever to shift into and out
of four-wheel drive.
An indicator light comes on when
four-wheel drive is engaged. See
Four-Wheel-Drive Light 0147.