2012 GMC SIERRA 1500 fuel

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.

Black plate (14,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-14 Driving and Operating
Blizzard Conditions
Being stuck in snow can be a
serious situation. Stay with the
vehicle unless there is help nearby.
If possible, use theRoadside
Assistance Program (U.S. and
Canada) on page 13‑7 orRoadside
Assistance Program (Mexico) on
page 13‑9. 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.
(Continued)
WARNING (Continued)
If the vehicle is stuck in the snow:
.Clear away snow from around
the base of your vehicle,
especially any that is blocking
the exhaust pipe.
.Check again from time to
time to be sure snow does
not collect there.
.Open a window about 5 cm
(2 in) on the side of the
vehicle 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 a setting that
circulates the air inside the
vehicle and set the fan speed
to the highest setting. See
“Climate Control Systems” in
the Index.
(Continued)
WARNING (Continued)
For more information about
carbon monoxide, see Engine
Exhaust on page 9‑33.
Run the engine for short periods
only as needed to keep warm, but
be careful.
To save fuel, run the engine for only
short periods as needed to warm
the vehicle and then shut the engine
off and close the window most of
the way to save heat. Repeat this
until help arrives but only when you
feel really uncomfortable from the
cold. Moving about to keep warm
also helps.

Black plate (15,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-15
If it takes some time for help to
arrive, now and then when you run
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 Your Vehicle to Get It
Out” later in this section.
If the vehicle has a traction system,
it can often help to free a stuck
vehicle. Refer to the vehicle's
traction system in the Index. If stuck
too severely for the traction system
to free the vehicle, turn the traction
system off and use the rocking
method.
{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 on page 10‑74.
Rocking Your 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 High. For vehicles with StabiliTrak
®, turn
the traction control part of the
system 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.
Release the accelerator pedal while
shifting, and press lightly on the
accelerator pedal when the
transmission is in gear. Slowly
spinning the wheels in the forward
and reverse directions causes a
rocking motion that could free the
vehicle. If that does not get the
vehicle out after a few tries, it might
need to be towed out. Recovery
hooks can be used, if the vehicle
has them. If the vehicle does need
to be towed out, see Towing the
Vehicle on page 10‑93.

Black plate (19,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-19
Example 3
A. Vehicle Capacity Weight for Example 3 = 453 kg (1,000 lbs)
B. Subtract Occupant Weight @ 91 kg (200 lbs) × 5 = 453 kg
(1,000 lbs)
C. Available Cargo Weight = 0 kg (0 lbs)
Refer to your vehicle's tire and
loading information label for
specific information about your
vehicle's capacity weight and
seating positions. The combined weight of the driver, passengers,
and cargo should never exceed
your vehicle's capacity weight.
Certification/Tire Label
A vehicle specific Certification/
Tire label is found on the rear
edge of the driver door. The
label shows the size of your
vehicle's original tires and the
inflation pressures needed
to obtain the gross weight
capacity of your vehicle.
This is called Gross Vehicle
Weight Rating (GVWR). The
GVWR includes the weight of
the vehicle, all occupants, fuel,
and cargo.
The Certification/Tire label also
tells you the maximum weights
for the front and rear axles,
called Gross Axle Weight
Rating (GAWR). To find out the
actual loads on your front and
rear axles, you need to go to a
weigh station and weigh your
vehicle. Your dealer can help
you with this. Be sure to spread
out your load equally on both
sides of the centerline.
Never exceed the GVWR for
your vehicle, or the GAWR for
either the front or rear axle.

Black plate (28,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-28 Driving and Operating
Starting Procedure
1. With your foot off the acceleratorpedal, turn the ignition key to
START. When the engine starts,
let go of the key. The idle speed
will go down as your 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.
The vehicle has a
Computer-Controlled Cranking
System. This feature assists in
starting the engine and protects
components. If the ignition key is
turned to the START position,
and then released when the
engine begins cranking, the
engine will continue cranking
for a few seconds or until the
vehicle starts. If the engine does
not start and the key is held in
START for many seconds,
cranking will be stopped after
15 seconds to prevent cranking
motor damage. To prevent gear damage, this system also
prevents cranking if the engine
is already running. Engine
cranking can be stopped by
turning the ignition switch
to the ACC/ACCESSORY or
LOCK/OFF position.
When the Low Fuel warning
lamp is on and the FUEL LEVEL
LOW message is displayed in
the Driver Information Center
(DIC), the Computer-Controlled
Cranking System is disabled
to prevent possible vehicle
component damage. When
this happens, hold the ignition
switch in the START position to
continue engine cranking.
Notice: Cranking the engine for
long periods of time, by returning
the key 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
5-10 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
as you hold 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.

Black plate (30,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-30 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
for more information.
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 Engine
Compartment Fuse Block with
a clip. Carefully remove the wire tie which bundles the
electrical plug. Do not cut the
electrical cord.
3. Plug the cord into a normal, grounded 110-volt AC outlet.
{WARNING
Plugging the cord into an
ungrounded outlet could cause an
electrical shock. Also, the wrong
kind of extension cord could
overheat and cause a fire. You
could be seriously injured. Plug
the cord into a properly grounded
three-prong 110-volt AC outlet.
If the cord will not reach, use a
heavy-duty three-prong extension
cord rated for at least 15 amps.
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
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
(Continued)

Black plate (32,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-32 Driving and Operating
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, then you will 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) with the shift lever
button fully released.
.Prevent movement of the shift
lever out of P (Park), unless the
ignition is in ON/RUN or ACC/
ACCESSORY 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 on
page 10‑88 for more information.
To shift out of P (Park) use the
following:
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.
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 V8 engines may
have Active Fuel Management™.
This system allows the engine to
operate on either all or half of its
cylinders, depending on the driving
conditions.

Black plate (33,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-33
When less power is required, such
as cruising at a constant vehicle
speed, the system will operate in
the half cylinder 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, seeDriver
Information Center (DIC) on
page 5‑30 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)
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.