2017 GMC SIERRA DENALI engine

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Driving and Operating 277To 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 Outlets 0 128 .
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
278 Driving and Operating
Engine Coolant Heater The engine heater can provide
easier starting and better fuel
economy during engine warm-up in
cold weather conditions at or below
− 18 °C (0 °F). Vehicles with an
engine heater should be plugged in
at least four hours before starting.
An internal thermostat in the
plug-end of the cord may exist,
which will prevent engine coolant
heater operation at temperatures
above − 18 °C (0 °F).
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
{ Warning
Do not plug in the engine block
heater while the vehicle is parked
in a garage or under a carport.
Property damage or personal
injury may result. Always park the
vehicle in a clear open area away
from buildings or structures. To Use the Engine Coolant
Heater 1. Turn off the engine.
2. Open the hood and unwrap the
electrical cord. The cord is
secured to the driver side
fender with a clip, next to the
engine compartment fuse
block. Carefully remove the
wire tie that bundles the
electrical plug. Do not cut the
electrical cord.
Check the heater cord for
damage. If it is damaged, do
not use it. See your dealer for
a replacement. Inspect the
cord for damage yearly.
3. Plug the cord into a normal,
grounded 110-volt AC outlet. { WarningImproper use of the heater cord
or an extension cord can damage
the cord and may result in
overheating and fire.
.
Plug the cord into a
three-prong electrical utility
receptacle that is protected
by a ground fault detection
function. An ungrounded
outlet could cause an
electric shock.
.
Use a weatherproof,
heavy-duty, 15 amp-rated
extension cord if needed.
Failure to use the
recommended extension
cord in good operating
condition, or using a
damaged heater or
extension cord, could make
(Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Driving and Operating 279Warning (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
{ WarningIt 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, see Driving Characteristics
and Towing Tips 0 320 .
1. Hold the brake pedal down,
then set the parking brake.
See Parking Brake 0 297 .
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
280 Driving and Operating Leaving the Vehicle with the
Engine Running
{ WarningIt can be dangerous to leave the
vehicle with the engine running.
The vehicle could move suddenly
if the shift lever is not fully in
P (Park) with the parking brake
firmly set.
If you have four-wheel drive and
the transfer case is in N (Neutral),
the vehicle will be free to roll,
even if the shift lever is in
P (Park). So be sure the transfer
case is in a drive gear – not in
N (Neutral).
And, if you leave the vehicle with
the engine running, it could
overheat and even catch fire. You
or others could be injured. Do not
leave the vehicle with the engine
running unless you have to.
If you have to leave the vehicle with
the engine running, be sure the
vehicle is in P (Park) and the parking brake is firmly set before
you leave it. After you move the shift
lever into P (Park), hold the regular
brake pedal down. Then, see if you
can move the shift lever away from
P (Park) without first pulling it toward
you. If you can, it means that the
shift lever was not fully locked into
P (Park).
Torque Lock If you are parking on a hill and you
do not shift the transmission into
P (Park) properly, the weight of the
vehicle may put too much force on
the parking pawl in the
transmission. You may find it difficult
to pull the shift lever out of P (Park).
This is called torque lock. To
prevent torque lock, set the parking
brake and then shift into P (Park)
properly before you leave the driver
seat. To find out how, see Shifting
Into Park 0 279 .
When you are ready to drive, move
the shift lever out of P (Park) before
you release the parking brake.
If torque lock does occur, you may
need to have another vehicle push
yours a little uphill to take some of the pressure from the parking pawl
in the transmission. You will then be
able to pull the shift lever out of
P (Park).
Shifting out of Park This vehicle is equipped with an
electronic shift lock release system.
The shift lock release is
designed to:
.
Prevent ignition key removal
unless the shift lever is in
P (Park).
.
Prevent movement of the shift
lever out of P (Park), unless the
ignition is in ON/RUN and the
regular brake pedal is applied.
The shift lock release is always
functional except in the case of an
uncharged or low voltage (less than
9 volt) battery.
If the vehicle has an uncharged
battery or a battery with low voltage,
try charging or jump starting the
battery. See Jump Starting - North
America 0 435 .

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Driving and Operating 281To shift out of P (Park):
1. Apply the brake pedal.
2. Move the shift lever to the
desired position.
If you still are unable to shift out of
P (Park):
1. Ease the pressure on the shift
lever.
2. While holding down the brake
pedal, press the shift lever all
the way into P (Park).
3. Move the shift lever to the
desired position.
If you are still having a problem
shifting, then have the vehicle
serviced soon.
This vehicle may have the Safety
Belt Assurance System, which may
prevent the vehicle from shifting out
of P (Park). See Safety Belt
Messages 0 163 . Parking over Things
That Burn
{ WarningThings that can burn could touch
hot exhaust parts under the
vehicle and ignite. Do not park
over papers, leaves, dry grass,
or other things that can burn.
Active Fuel Management Vehicles with a V8 or V6 gasoline
engine may have Active Fuel
Management. This system allows
the engine to operate on either all of
its cylinders, or in V4 mode,
depending on the driving conditions.
When less power is required, such
as cruising at a constant vehicle
speed, the system will operate in
the V4 mode, allowing the vehicle to
achieve better fuel economy. When
greater power demands are
required, such as accelerating from
a stop, passing, or merging onto a
freeway, the system will maintain
full-cylinder operation. If the vehicle has an Active Fuel
Management indicator, see Driver
Information Center (DIC) (Base
Level Cluster) 0 152 or Driver
Information Center (DIC) (Uplevel
and Denali Cluster) 0 154 for more
information on using this display.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
282 Driving and Operating
Engine Exhaust
{ WarningEngine exhaust contains carbon
monoxide (CO), which cannot be
seen or smelled. Exposure to CO
can cause unconsciousness and
even death.
Exhaust may enter the vehicle if:
.
The vehicle idles in areas
with poor ventilation
(parking garages, tunnels,
deep snow that may block
underbody airflow or tail
pipes).
.
The exhaust smells or
sounds strange or different.
.
The exhaust system leaks
due to corrosion or damage.
.
The vehicle exhaust system
has been modified,
damaged, or improperly
repaired.
(Continued) Warning (Continued) .
There are holes or openings
in the vehicle body from
damage or aftermarket
modifications that are not
completely sealed.
If unusual fumes are detected or
if it is suspected that exhaust is
coming into the vehicle:
.
Drive it only with the
windows completely down.
.
Have the vehicle repaired
immediately.
Never park the vehicle with the
engine running in an enclosed
area such as a garage or a
building that has no fresh air
ventilation. Running the Vehicle
While Parked It is better not to park with the
engine running.
If the vehicle is left with the engine
running, follow the proper steps to
be sure the vehicle will not move.
See Shifting Into Park 0 279 and
Engine Exhaust 0 282 .
If parking on a hill and pulling a
trailer, see Driving Characteristics
and Towing Tips 0 320 .

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Driving and Operating 283
Automatic
Transmission If equipped, there is an electronic
shift lever position indicator within
the instrument cluster. This display
comes on when the ignition key is
turned to the ON/RUN position.
There are several different positions
for the shift lever.
Heavy-Duty 6-Speed Automatic
Transmission Shown, Others
Similar
See “ Range Selection Mode ” under
Manual Mode 0 286 .
P : This position locks the rear
wheels. It is the best position to use
when starting the engine because
the vehicle cannot move easily.
When parked on a hill, especially
when the vehicle has a heavy load,
you might notice an increase in the effort to shift out of P (Park). See
“ Torque Lock ” under Shifting Into
Park 0 279 .
{ WarningIt is 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.
Do not leave the vehicle when the
engine is running. 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,
always set the parking brake and
move the shift lever to P (Park).
See Shifting Into Park 0 279 and
Driving Characteristics and
Towing Tips 0 320 .{ WarningIf you have four-wheel drive, the
vehicle will be free to roll — even
if the shift lever is in P (Park) — if
the transfer case is in N (Neutral).
So, be sure the transfer case is in
a drive gear, Two-Wheel Drive
High or Four-Wheel Drive High or
Four-Wheel Drive Low — not in
N (Neutral). See Shifting Into Park
0 279 .
R : Use this gear to back up.
CautionShifting to R (Reverse) while the
vehicle is moving forward could
damage the transmission. The
repairs would not be covered by
the vehicle warranty. Shift to
R (Reverse) only after the vehicle
is stopped.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
284 Driving and Operating To rock the vehicle back and forth to
get out of snow, ice, or sand without
damaging the transmission, see If
the Vehicle Is Stuck 0 264 .
N : In this position, the engine does
not connect with the wheels. To
restart when you are already
moving, use N (Neutral) only. Also,
use N (Neutral) when the vehicle is
being towed.
{ WarningShifting into a drive gear while the
engine is running at high speed is
dangerous. Unless your foot is
firmly on the brake pedal, the
vehicle could move very rapidly.
You could lose control and hit
people or objects. Do not shift
into a drive gear while the engine
is running at high speed. CautionShifting out of P (Park) or
N (Neutral) with the engine
running at high speed may
damage the transmission. The
repairs would not be covered by
the vehicle warranty. Be sure the
engine is not running at high
speed when shifting the vehicle.
D : This position is for normal
driving. It provides the best fuel
economy. If you need more power
for passing, and you are:
.
Going less than about 55 km/h
(35 mph), push the accelerator
pedal about halfway down.
.
Going about 55 km/h (35 mph) or
more, push the accelerator all
the way down.
By doing this, the vehicle shifts
down to the next gear and has
more power.
Use D (Drive) and Tow/Haul Mode
when towing a trailer, carrying a
heavy load, driving on steep hills, or driving off-road. Shift the
transmission to a lower gear
selection if the transmission shifts
too often.
Downshifting the transmission in
slippery road conditions could result
in skidding. See “ Skidding ” under
Loss of Control 0 256 .
The vehicle has a shift stabilization
feature that adjusts the transmission
shifting to the current driving
conditions in order to reduce rapid
upshifts and downshifts. This shift
stabilization feature is designed to
determine, before making an
upshift, if the engine is able to
maintain vehicle speed by analyzing
things such as vehicle speed,
throttle position, and vehicle load.
If the shift stabilization feature
determines that a current vehicle
speed cannot be maintained, the
transmission does not upshift and
instead holds the current gear.
In some cases, this could appear to
be a delayed shift, however the
transmission is operating normally.