maint GMC SIERRA 2018 Owner's Guide

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
232 Climate Controls
Maintenance
Passenger Compartment
Air Filter
The filter reduces the dust, pollen,
and other airborne irritants from
outside air that is pulled into the
vehicle.
The filter should be replaced as part
of routine scheduled maintenance.
SeeMaintenance Schedule 0448.
To find out what type of filter to use,
see Maintenance Replacement
Parts 0458.
1. Open the lower glove box door
completely.
2. Remove the four screws from around the lower glove box.
The door does not need to be
removed to access the screws.
3. Close the lower glove box doorand pull it from its frame to
remove the entire unit.
4. Release the two tabs holding
the service door. Open the
service door and remove the
old filter.
5. Install the new air filter.
6. Close the service door and secure the tabs.
7. Reverse the steps to reinstall the glove box.
See your dealer if additional
assistance is needed.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 237
If the engine ever stops while the
vehicle is being driven, brake
normally but do not pump the
brakes. Doing so could make the
pedal harder to push down. If the
engine stops, there will be some
power brake assist but it will be
used when the brake is applied.
Once the power assist is used up, it
can take longer to stop and the
brake pedal will be harder to push.
Steering
Electric Power Steering (1500
Series)
If the vehicle has electric power
steering, it does not have power
steering fluid. Regular maintenance
is not required.
If power steering assist is lost due
to a system malfunction, the vehicle
can be steered, but may require
increased effort. See your dealer if
there is a problem.If the steering wheel is turned until it
reaches the end of its travel, and is
held in that position for an extended
period of time, power steering assist
may be reduced.
If the steering assist is used for an
extended period of time while the
vehicle is not moving, power assist
may be reduced.
Normal use of the power steering
assist should return when the
system cools down.
See your dealer if there is a
problem.Hydraulic Power Steering
(2500/3500 Series)
(2500/3500 Series
–All Regular
Cab, Double Cab/Crew Cab
without Digital Steer Assist)
The power steering system may
require maintenance. See Power
Steering Fluid (1500 Series) 0365
or Power Steering Fluid (2500/3500
Series) 0365. If power steering assist is lost
because the engine stops or the
system malfunctions, the vehicle
can be steered but may require
increased effort. See your dealer.
(2500/3500 Series
–Double Cab/
Crew Cab with Digital Steer
Assist)
The vehicle has a Digital Steer
Assist power steering system that
varies the amount of effort required
to steer the vehicle. Less steering
effort is required at slower speeds.
At faster speeds, the steering effort
increases. The system helps the
steering wheel return to center at
low speeds. Pressing the Tow/Haul
button adjusts steering effort for
driving conditions described in Tow/
Haul Mode 0271.
The power steering system may
require maintenance. See Power
Steering Fluid (1500 Series) 0365
or Power Steering Fluid (2500/3500
Series) 0365.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
238 Driving and Operating
If power steering assist is lost
because the engine stops or the
system malfunctions, the vehicle
can be steered but may require
increased effort. See your dealer.
Caution
If the steering wheel is turned
until it reaches the end of its
travel, and is held in that position
for more than 15 seconds,
damage may occur to the power
steering system and there may be
loss of power steering assist.
Curve Tips
.Take curves at a reasonable
speed.
. Reduce speed before entering a
curve.
. Maintain a reasonable steady
speed through the curve.
. Wait until the vehicle is out of
the curve before accelerating
gently into the straightaway.
Steering in Emergencies
.There are some situations when
steering around a problem may
be more effective than braking.
. Holding both sides of the
steering wheel allows you to turn
180 degrees without removing
a hand.
. Antilock Brake System (ABS)
allows steering while braking.
Off-Road Recovery
The vehicle's right wheels can drop
off the edge of a road onto the
shoulder while driving. Follow
these tips:
1. Ease off the accelerator and then, if there is nothing in the
way, steer the vehicle so that it
straddles the edge of the
pavement.
2. Turn the steering wheel about one-eighth of a turn, until the
right front tire contacts the
pavement edge.
3. Turn the steering wheel to go straight down the roadway.
Loss of Control
Skidding
There are three types of skids that
correspond to the vehicle's three
control systems:
.Braking Skid —wheels are not
rolling.
. Steering or Cornering Skid —
too much speed or steering in a
curve causes tires to slip and
lose cornering force.

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
Driving and Operating 241
Warning (Continued)
cause a rollover. You could be
injured or killed. Do not drive on
steep hills.
Before driving on a hill, assess the
steepness, traction, and
obstructions. If the terrain ahead
cannot be seen, get out of the
vehicle and walk the hill before
driving further.
When driving on hills:
. Use a low gear and keep a firm
grip on the steering wheel.
. Maintain a slow speed.
. When possible, drive straight up
or down the hill.
. Slow down when approaching
the top of the hill.
. Use headlamps even during the
day to make the vehicle more
visible.
{Warning
Driving to the top of a hill at high
speed can cause an accident.
There could be a drop-off,
embankment, cliff, or even
another vehicle. You could be
seriously injured or killed. As you
near the top of a hill, slow down
and stay alert.
. Never go downhill forward or
backward with either the
transmission or transfer case in
N (Neutral). The brakes could
overheat and you could lose
control.
{Warning
If the vehicle has the two-speed
automatic or electronic transfer
case, shifting the transfer case to
N (Neutral) can cause your
vehicle to roll even if the
transmission is in P (Park). This is
(Continued)
Warning (Continued)
because the N (Neutral) position
on the transfer case overrides the
transmission. You or someone
else could be injured. If leaving
the vehicle, set the parking brake
and shift the transmission to
P (Park). Shift the transfer case to
any position but N (Neutral).
. When driving down a hill, keep
the vehicle headed straight
down. Use a low gear because
the engine will work with the
brakes to slow the vehicle and
help keep the vehicle under
control.
{Warning
Heavy braking when going down
a hill can cause your brakes to
overheat and fade. This could
cause loss of control and you or
others could be injured or killed.
(Continued)

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
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.
(Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 267
Caution
Shifting 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.
Caution
A transmission hot message may
display if the automatic
transmission fluid is too hot.
Driving under this condition can
damage the vehicle. Stop and idle
the engine to cool the automatic
transmission fluid. This message
clears when the transmission fluid
has cooled sufficiently.D :
This position is for normal
driving. It provides the best fuel
economy. If more power is needed
for passing, press the accelerator
pedal down.
. 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 0238. 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.
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

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
268 Driving and Operating
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 0268.
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.
(Continued)
Caution (Continued)
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.
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. For other forms of grade braking,
see
Tow/Haul Mode 0271 and
Cruise Control 0285.
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.
Manual Mode
Range Selection Mode
If equipped, Range Selection Mode
helps control the vehicle's
transmission and vehicle speed
while driving downhill or towing a
trailer by letting you select a desired
range of gears.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 271
Low 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 L2 using
Range Selection Mode. This will
limit torque to the wheels and help
to prevent the tires from spinning.
Tow/Haul Mode
Vehicles with an automatic
transmission have a Tow/Haul
Mode. The Tow/Haul Mode adjusts
the transmission shift pattern to
reduce shift cycling. This providesincreased performance, vehicle
control, and enhanced transmission
and engine cooling when driving
down steep hills or mountain
grades, when towing, or when
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.
For an eAssist vehicle, the Stop/
Start function will become
unavailable when Tow/Haul Mode is
active.
For an eAssist vehicle, the
Regenerative Braking functionality is
disabled when using the Tow/Haul
Mode. See the eAssist supplement.
See
Tow/Haul Mode Light 0153 and
Hill and Mountain Roads 0245.
Also see “Tow/Haul Mode” under
Towing Equipment 0325.
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 Mode0268.
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.
If equipped, 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.