2012 GMC SIERRA 1500 automatic transmission

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 (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 (8,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-8 Driving and Operating
.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 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 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.
Apply the brakes lightly when
descending a hill and use a low
gear to keep vehicle speed under
control.
If the vehicle stalls on a hill:
1. Apply the brakes to stop the vehicle, and then apply the
parking brake.
2. Shift into P (Park) for an automatic transmission
or 1 (First) for a manual
transmission and then restart
the engine.
.If driving uphill when the
vehicle stalls, shift to
R (Reverse), release the
parking brake, and back
straight down.

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 (26,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-26 Driving and Operating
Ignition Positions
The ignition switch has four different
positions.
To shift out of P (Park), the ignition
must be in ON/RUN or ACC/
ACCESSORY and the regular brake
pedal must be applied.
A (STOPPING THE ENGINE/
LOCK/OFF):When the vehicle is
stopped, turn the ignition switch to
LOCK/OFF to turn the engine off.
Retained Accessory Power (RAP) will remain active. See
Retained
Accessory Power (RAP) on
page 9‑29.
This position locks the ignition.
It also locks the transmission on
automatic transmission vehicles.
The key can be removed in
LOCK/OFF.
Do not turn the engine off when the
vehicle is moving. This will cause a
loss of power assist in the brake
and steering systems and disable
the airbags.
If the vehicle must be shut off in an
emergency:
1. Brake using a firm and steady pressure. Do not pump the
brakes repeatedly. This may
deplete power assist, requiring
increased brake pedal force.
2. Shift the vehicle to N (Neutral). This can be done while the
vehicle is moving. After shifting
to N (Neutral), firmly apply the
brakes and steer the vehicle to a
safe location. 3. Come to a complete stop, shift
to P (Park), and turn the ignition
to LOCK/OFF. On vehicles with
an automatic transmission, the
shift lever must be in P (Park) to
turn the ignition switch to the
LOCK/OFF position.
4. Set the parking brake. See Parking Brake on page 9‑54.
{WARNING
Turning off the vehicle while
moving may cause loss of power
assist in the brake and steering
systems and disable the airbags.
While driving, only shut the
vehicle off in an emergency.
If the vehicle cannot be pulled
over, and must be shut off while
driving, turn the ignition to ACC/
ACCESSORY.

Black plate (27,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-27
The steering can bind with the
wheels turned off center. If this
happens, move the steering wheel
from right to left while turning the
key to ACC/ACCESSORY. If this
does not work, then the vehicle
needs service.
Notice:Using a tool to force the
key to turn in the ignition could
cause damage to the switch or
break the key. Use the correct
key, make sure it is all the way in,
and turn it only with your hand.
If the key cannot be turned by
hand, see your dealer.
B (ACC/ACCESSORY): This
position lets things like the radio
and the windshield wipers operate
while the engine is off. Use this
position if the vehicle must be
pushed or towed.
C (ON/RUN): This position can
be used to operate the electrical
accessories and to display some
instrument panel cluster warning
and indicator lights. This position
can also be used for service and diagnostics, and to verify the
proper operation of the malfunction
indicator lamp as may be required
for emission inspection purposes.
The switch stays in this position
when the engine is running. The
transmission is also unlocked in this
position on automatic transmission
vehicles.
If you leave the key in the ACC/
ACCESSORY or ON/RUN position
with the engine off, the battery could
be drained. You may not be able to
start the vehicle if the battery is
allowed to drain for an extended
period of time.
D (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 more information.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
Notice: 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.
Move the shift lever to P (Park) or
N (Neutral). The engine will not start
in any other position. To restart the
engine when the vehicle is already
moving, use N (Neutral) only.
Notice: 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
on page 9‑105.

Black plate (34,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-34 Driving and Operating
Running the Vehicle
While Parked
It is better not to park with the
engine running. But if you ever have
to, here are some things to know.
{WARNING
Idling a vehicle in an enclosed
area with poor ventilation is
dangerous. Engine exhaust may
enter the vehicle. Engine exhaust
contains carbon monoxide (CO)
which cannot be seen or smelled.
It can cause unconsciousness
and even death. Never run the
engine in an enclosed area that
has no fresh air ventilation. For
more information, seeEngine
Exhaust on page 9‑33.
{WARNING
It can be dangerous to get out
of the vehicle if the automatic
transmission 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 unless you
have to. 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).
{WARNING
Four-wheel drive vehicles with
the transfer case in N (Neutral)
will allow the vehicle to roll, even
if the automatic transmission
shift lever is in P (Park). So, be
sure the transfer case is in a drive
gear —not in N (Neutral). Always
set the parking brake.
Follow the proper steps to be sure
the vehicle will not move. See
Shifting Into Park on page 9‑30.
If pulling a trailer, see Driving
Characteristics and Towing Tips on
page 9‑74.

Black plate (35,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-35
Automatic
Transmission
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
Vehicles with an automatic
transmission have an electronic
shift position indicator within the
instrument panel 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.
Hydra-Matic®4-Speed Automatic
Transmission
Heavy Duty 6-Speed Automatic
Transmission Shown (Light Duty 6‐Speed Similar)
See “Range Selection Mode” under
Manual Mode on page 9‑38.
P (Park): 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 on page 9‑30 for
more information.
{WARNING
It 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 unless
you have to. 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 on
page 9‑30. If you are pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9‑74.