2018 GMC SIERRA fuel

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 239
.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.
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 seat 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.
. Know the local laws that apply to
off-road driving.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
240 Driving and Operating
To gain more ground clearance if
needed, it may be necessary to
remove the front fascia lower air
dam, if equipped. However, driving
without the air dam reduces fuel
economy.
Caution
Operating the vehicle for
extended periods without the front
fascia lower air dam installed can
cause improper airflow to the
engine. Reattach 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
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Warning (Continued)
passengers can be struck
by flying objects. Secure the
cargo properly.
. 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
0 248 andTires 0389.
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 0264.
Driving on Hills
Driving safely on hills requires good
judgment and an understanding of
what the vehicle can and cannot do.
{Warning
Many 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
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GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
244 Driving and Operating
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, driveline,
steering, suspension, 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 theMaintenance
Schedule 0448.
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.
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 Tires0389.
. Turn off cruise control.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
246 Driving and Operating
.Allow greater following distance
and watch for slippery spots. Icy
patches can occur on otherwise
clear roads in shaded areas.
The surface of a curve or an
overpass can remain icy when
the surrounding roads are clear.
Avoid sudden steering
maneuvers and braking while
on ice.
. Turn off cruise control.
Blizzard Conditions
Stop the vehicle in a safe place and
signal for help. Stay with the vehicle
unless there is help nearby.
If possible, use Roadside
Assistance. See Roadside
Assistance Program 0469. To get
help and keep everyone in the
vehicle safe:
. Turn on the hazard warning
flashers.
. Tie a red cloth to an outside
mirror.
{Warning
Snow can trap engine exhaust
under the vehicle. This may
cause exhaust gases to get
inside. Engine exhaust contains
carbon monoxide (CO), which
cannot be seen or smelled. It can
cause unconsciousness and even
death.
If the vehicle is stuck in snow:
. 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
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Warning (Continued)
the fan speed to the highest
setting. See“Climate
Control Systems.”
For more information about CO,
see Engine Exhaust 0264.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 251
of the driver, passengers, and
cargo should never exceed the
vehicle's capacity weight.
Certification/Tire Label
A vehicle-specific Certification/
Tire label is label is attached to
the center pillar (B-pillar). The
label may show the size of the
vehicle's original tires and the
inflation pressures needed to
obtain the gross weight capacity
of the vehicle. This is called
Gross Vehicle Weight
Rating (GVWR). The GVWRincludes the weight of the
vehicle, all occupants, fuel, and
cargo.
The Certification/Tire label also
may show the maximum weights
for the front and rear axles,
called Gross Axle Weight
Rating (GAWR). To determine
the actual loads on the front and
rear axles, weigh the vehicle at
a weigh station. Your dealer can
help with this. Be sure to spread
the load equally on both sides of
the centerline.
The Certification/Tire label also
contains important information
about the Front Axle Reserve
Capacity. See
Adding a Snow
Plow or Similar Equipment
0 337.
{Warning
In the case of a sudden stop
or collision, things carried in
the bed of your truck could
shift forward and come into
the passenger area, injuring
you and others. If you put
things in the bed of your truck,
you should make sure they
are properly secured.
Caution
Overloading the vehicle may
cause damage. Repairs would not
be covered by the vehicle
warranty. Do not overload the
vehicle.
Using heavier suspension
components to get added
durability might not change the
weight ratings. Ask your dealer
to help load the vehicle the
right way.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
258 Driving and Operating
The switch stays in this position
when the engine is running. The
transmission is also unlocked in this
position.
If the key is left in the ACC/
ACCESSORY or ON/RUN position
with the engine off, the battery could
be drained. The vehicle may not
start if the battery is allowed to drain
for an extended period of time.
3 (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.
For an eAssist vehicle, see the
Silverado/Sierra eAssist
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
0 336.
Caution
If 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 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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
260 Driving and Operating
.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 Outlets0133.
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.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
264 Driving and Operating
Parking over Things
That Burn
{Warning
Things 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) (Uplevel
and Denali Cluster) 0160 orDriver
Information Center (DIC) (Base
Level Cluster) 0158 for more
information on using this display.
Engine Exhaust
{Warning
Engine 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.
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