wheel GMC SIERRA 1500 2012 Owner's Guide

Black plate (10,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
8-10 Climate Controls
The interior temperature sensor,
located in the headliner, measures
the temperature of the air inside the
vehicle.There is also an exterior
temperature sensor located behind
the front grille. This sensor reads
the outside air temperature and
helps maintain the temperature
inside the vehicle. Any cover on the
front of the vehicle could cause a
false reading in the displayed
temperature.
The climate control system uses the
information from these sensors to
maintain comfort settings by
adjusting the outlet temperature, fan
speed, and the air delivery mode.
The system may also supply cooler
air to the side of the vehicle facing
the sun. The recirculation mode will
also be used as needed to maintain
cool outlet temperatures.
Air Vents
Use the air outlets located in the
center and on the side of the
instrument panel to direct the
airflow. Use the thumbwheels near
the air outlets to open or close off
the airflow.
Operation Tips
.Clear away any ice, snow,
or leaves from air inlets at the
base of the windshield that could
block the flow of air into the
vehicle.
.Keep the path under the front
seats clear of objects to help
circulate the air inside of the
vehicle more effectively.
.Use of non‐GM approved hood
deflectors can adversely affect
the performance of the system.
Check with your dealer before
adding equipment to the outside
of the vehicle.

Black plate (1,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
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 . . . . . . . . . . . 9-4
Braking . . . . . . . . . . . . . . . . . . . . . . . 9-4
Steering . . . . . . . . . . . . . . . . . . . . . . . 9-4
Off-Road Recovery . . . . . . . . . . . . 9-5
Loss of Control . . . . . . . . . . . . . . . . 9-5
Off-Road Driving . . . . . . . . . . . . . . 9-6
Driving on Wet Roads . . . . . . . . 9-11
Highway Hypnosis . . . . . . . . . . . 9-12
Hill and Mountain Roads . . . . . 9-12
Winter Driving . . . . . . . . . . . . . . . 9-13
If the Vehicle Is Stuck . . . . . . . . 9-15
Vehicle Load Limits . . . . . . . . . . 9-16
Truck-Camper LoadingInformation . . . . . . . . . . . . . . . . . 9-23
Starting and Operating
New Vehicle Break-In . . . . . . . . 9-25
Adjustable Throttle and BrakePedal . . . . . . . . . . . . . . . . . . . . . . . 9-25
Ignition Positions . . . . . . . . . . . . 9-26 Starting the Engine . . . . . . . . . . 9-27
Fast Idle System . . . . . . . . . . . . . 9-29
Retained Accessory
Power (RAP) . . . . . . . . . . . . . . . 9-29
Engine Coolant Heater . . . . . . . 9-30
Shifting Into Park . . . . . . . . . . . . 9-30
Shifting out of Park . . . . . . . . . . 9-32
Parking over Things
That Burn . . . . . . . . . . . . . . . . . . 9-32
Active Fuel Management
®. . . 9-32
Engine Exhaust
Engine Exhaust . . . . . . . . . . . . . . 9-33
Running the Vehicle While Parked . . . . . . . . . . . . . . . . . . . . . 9-34
Automatic Transmission
Automatic Transmission . . . . . 9-35
Manual Mode . . . . . . . . . . . . . . . . 9-38
Tow/Haul Mode . . . . . . . . . . . . . . 9-39
Drive Systems
Four-Wheel Drive . . . . . . . . . . . . 9-40
Brakes
Antilock BrakeSystem (ABS) . . . . . . . . . . . . . . 9-53
Parking Brake . . . . . . . . . . . . . . . 9-54
Brake Assist . . . . . . . . . . . . . . . . . 9-54
Hill Start Assist (HSA) . . . . . . . 9-54
Ride Control Systems
StabiliTrak®System . . . . . . . . . 9-55
Locking Rear Axle . . . . . . . . . . . 9-58
Cruise Control
Cruise Control . . . . . . . . . . . . . . . 9-58
Object Detection Systems
Ultrasonic Parking Assist . . . . 9-61
Rear Vision Camera (RVC) . . . . . . . . . . . . . 9-62
Fuel
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . 9-68
Recommended Fuel . . . . . . . . . 9-68
Gasoline Specifications (U.S.and Canada Only) . . . . . . . . . . 9-69
California Fuel Requirements . . . . . . . . . . . . . . 9-69
Fuels in Foreign Countries . . . 9-69
Fuel Additives . . . . . . . . . . . . . . . 9-70
Fuel E85 (85% Ethanol) . . . . . 9-71
Filling the Tank . . . . . . . . . . . . . . 9-72
Filling a Portable Fuel Container . . . . . . . . . . . . . . . . . . . 9-73

Black plate (2,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-2 Driving and Operating
Towing
General TowingInformation . . . . . . . . . . . . . . . . . 9-74
Driving Characteristics and Towing Tips . . . . . . . . . . . . . . . . 9-74
Trailer Towing . . . . . . . . . . . . . . . . 9-78
Towing Equipment . . . . . . . . . . . 9-94
Trailer Sway
Control (TSC) . . . . . . . . . . . . . 9-105
Conversions and Add-Ons
Add-On ElectricalEquipment . . . . . . . . . . . . . . . . 9-105
Adding a Snow Plow or Similar Equipment . . . . . . . . 9-106
Pickup Conversion to Chassis Cab . . . . . . . . . . . . . . 9-109
Driving Information
Distracted Driving
Distraction comes in many forms
and can take your focus from the
task of driving. Exercise good
judgment and do not let other
activities divert your attention
away from the road. Many local
governments have enacted laws
regarding driver distraction.
Become familiar with the local
laws in your area.
To avoid distracted driving, always
keep your eyes on the road, hands
on the wheel, and mind on the drive.
.Do not use a phone in
demanding driving situations.
Use a hands-free method to
place or receive necessary
phone calls.
.Watch the road. Do not
read, take notes, or look up
information on phones or other
electronic devices.
.Designate a front seat
passenger to handle potential
distractions.
.Become familiar with vehicle
features before driving, such as
programming favorite radio
stations and adjusting climate
control and seat settings.
Program all trip information into
any navigation device prior to
driving.
.Wait until the vehicle is parked
to retrieve items that have fallen
to the floor.
.Stop or park the vehicle to tend
to children.
.Keep pets in an appropriate
carrier or restraint.
.Avoid stressful conversations
while driving, whether with a
passenger or on a cell phone.

Black plate (4,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-4 Driving and Operating
Control of a Vehicle
Braking, steering, and accelerating
are important factors in helping to
control a vehicle while driving.
Braking
Braking action involves perception
time and reaction time. Deciding
to push the brake pedal is
perception time. Actually doing
it is reaction time.
Average driver reaction time is
about three-quarters of a second.
In that time, a vehicle moving at
100 km/h (60 mph) travels 20 m
(66 ft), which could be a lot of
distance in an emergency.
Helpful braking tips to keep in mind
include:
.Keep enough distance between
you and the vehicle in front
of you.
.Avoid needless heavy braking.
.Keep pace with traffic.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
Hydraulic Power Steering
Your vehicle has hydraulic
power steering. It may require
maintenance. See Power Steering
Fluid
Power Steering Fluid on
page 10‑25.
If power steering assist is lost
because the engine stops or the
power steering system is not
functioning, the vehicle can be
steered but may required increased
effort. See your dealer if there is a
problem. If the vehicle is a hybrid, see the
hybrid supplement for more
information.
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.

Black plate (5,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-5
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 andthen, 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. Then 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.
.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 quickly
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.

Black plate (6,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-6 Driving and Operating
.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. To
contact the tire manufacturer for
more information about the original
equipment tires, see the Limited
Warranty and Owner Assistance
Information manual.
Controlling the vehicle is the key to
successful off-road driving. One of
the best ways to control the vehicle
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 safety 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.
.Make sure all underbody
shields, if equipped, are properly
attached.
.Know the local laws that apply to
off-road driving. To gain more ground clearance if
needed, it may be necessary to
remove the front fascia lower
air dam.
Notice:
Operating the vehicle
for extended periods without
the front fascia lower air dam
installed can cause improper air
flow to the engine. Re‐attach 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
passengers can be struck by
flying objects. Secure the
cargo properly.
(Continued)

Black plate (7,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-7
WARNING (Continued)
.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
and Tires.
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..
Driving on Hills
Driving safely on hills requires good
judgment and an understanding of
what the vehicle can and cannot do.
{WARNING
If the vehicle has the two‐speed
automatic transfer case, shifting
the transfer case to N (Neutral)
can cause your vehicle to roll
even if the transmission is in
P (Park) for an automatic
transmission or any gear position
for a manual transmission. This is
because the N (Neutral) position
on the transfer case overrides the
transmission. You or someone
else could be injured. If leaving (Continued)
WARNING (Continued)
the vehicle, set the parking
brake and shift the transmission
to P (Park) for an automatic
transmission or any gear position
for a manual transmission. Shift
the transfer case to any position
but N (Neutral).
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.

Black plate (9,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-9
.Never try to turn the vehicle
around. If the hill is steep
enough to stall the vehicle,
it is steep enough to cause
it to roll over.
.If you cannot make it up the
hill, back straight down
the hill.
.Never back down a hill in
N (Neutral) using only the
brake.
.The vehicle can roll
backward quickly and you
could lose control.
.If driving downhill when the
vehicle stalls, shift to a
lower gear, release the
parking brake, and drive
straight down the hill.3. If the vehicle cannot be restarted
after stalling, set the parking
brake, shift an automatic
transmission into P (Park) or
a manual transmission into
1 (First), and turn the vehicle off.
3.1. Leave the vehicle and
seek help.
3.2. Stay clear of the path the vehicle would take if it
rolled downhill.
.Avoid turns that take the vehicle
across the incline of the hill.
A hill that can be driven straight
up or down might be too steep to
drive across. Driving across an
incline puts more weight on the
downhill wheels which could
cause a downhill slide or a
rollover.
.Surface conditions can be a
problem. Loose gravel, muddy
spots, or even wet grass can
cause the tires to slip sideways,
downhill. If the vehicle slips sideways, it can hit something
that will trip it
–a rock, a rut,
etc. –and roll over.
.Hidden obstacles can make the
steepness of the incline more
severe. If a rock is driven across
with the uphill wheels, or if the
downhill wheels drop into a rut
or depression, the vehicle can tilt
even more.
.If an incline must be driven
across, and the vehicle starts to
slide, turn downhill. This should
help straighten out the vehicle
and prevent the side slipping.
{WARNING
Getting out of the vehicle on the
downhill side when stopped
across an incline is dangerous.
If the vehicle rolls over, you could
be crushed or killed. Always get
out on the uphill side of the
vehicle and stay well clear of the
rollover path.

Black plate (10,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-10 Driving and Operating
Driving in Mud, Sand, Snow,
or Ice
Use a low gear when driving in
mud–the deeper the mud, the
lower the gear. Keep the vehicle
moving to avoid getting stuck.
Traction changes when driving on
sand. On loose sand, such as on
beaches or sand dunes, the tires
tend to sink into the sand. This
affects steering, accelerating, and
braking. Drive at a reduced speed
and avoid sharp turns or abrupt
maneuvers.
Traction is reduced on hard packed
snow and ice and it is easy to lose
control. Reduce vehicle speed when
driving on hard packed snow
and ice.
{WARNING
Driving on frozen lakes, ponds,
or rivers can be dangerous. Ice
conditions vary greatly and the
vehicle could fall through the ice;
you and your passengers could
drown. Drive your vehicle on safe
surfaces only.
Driving in Water
{WARNING
Driving through rushing water can
be dangerous. Deep water can
sweep your vehicle downstream
and you and your passengers
could drown. If it is only shallow
water, it can still wash away the
ground from under your tires.
Traction could be lost, and the
vehicle could roll over. Do not
drive through rushing water. Notice:
Do not drive through
standing water if it is deep
enough to cover the wheel hubs,
axles or exhaust pipe. Deep water
can damage the axle and other
vehicle parts.
If the standing water is not too deep,
drive slowly through it. At faster
speeds, water splashes on the
ignition system and the vehicle can
stall. Stalling can also occur if you
get the exhaust pipe under water.
While the exhaust pipe is under
water, you will not be able to start
the engine. When going through
water, the brakes get wet, and it
might take longer to stop. See
Driving on Wet Roads.
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.

Black plate (11,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-11
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, 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. Refer to the
Maintenance Schedule for more
information.
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.