
Black plate (36,1)GMC Sierra Owner Manual - 2011
9-36 Driving and Operating
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 9‑40.
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. 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 neutral. This can be done while the vehicle is
moving. After shifting to 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 9‑69. 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
doesn't 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.

Black plate (37,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-37
C (ON/RUN):This position can
be used to operate the electrical
accessories and to display some
instrument panel cluster warning
and indicator lights. 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 Duramax 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: The engine is designed to
work with the electronics in the
vehicle. If you add electrical parts
or accessories, you could change
the way the engine operates. Before adding electrical
equipment, check with your
dealer. If you do not, the engine
might not perform properly.
Any resulting damage would
not be covered by the vehicle
warranty.
Starting Procedure
1. With your foot off the accelerator
pedal, 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.

Black plate (38,1)GMC Sierra Owner Manual - 2011
9-38 Driving and Operating
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 (39,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-39
Fast Idle System
If the vehicle has this feature it is
available only with cruise control.
The manual fast idle switch is
operated using the cruise control
buttons located on the left hand
side of the steering wheel.
This system can be used to
increase engine idle speed
whenever the following conditions
are met:
.The park brake is set.
.The brake pedal is not pressed.
.The vehicle must not be moving
and the accelerator must not be
pressed.To control the fast idle:
.To enable the Fast Idle System,
press and release the Cruise
Control On/Off button and
ensure that the switch LED is lit.
.Press and release the Cruise
Control Set switch. Engine
speed will be held at
approximately 1200 RPM.
When the fast idle is active the
Driver Information Center (DIC) will
display “FAST IDLE ON.”
One of the following actions will turn
off the fast idle:
.Pressing the brake.
.Selecting the Cruise Control
Cancel button.
.Releasing the Parking Brake.
.The transmission shifter is
moved out of P (Park) or
N (Neutral).
.Selecting the Cruise Control
On/Off button when it was
previously on.
.Pressing the Cruise Control Set
switch a second time.
.Pressing the accelerator greater
than a quarter of the down.
.Turning the ignition switch to the
LOCK/OFF position.

Black plate (41,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-41
WARNING (Continued)
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
gear —not in N (Neutral). If you
are pulling a trailer, see Driving
Characteristics and Towing Tips
on page 9‑91. 1. Hold the brake pedal down, then
set the parking brake.
See Parking Brake on page 9‑69
for more information.
2. Move the shift lever into the P (Park) position by pulling
the shift lever toward you and
moving it up as far as it will go.
3. Be sure the transfer case is in a drive gear —not in N (Neutral).
4. Turn the ignition key to LOCK/OFF.
5. Remove the key and take it with you. If you can leave the vehicle
with the ignition key in your
hand, the vehicle is in P (Park).

Black plate (43,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-43
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 10‑98 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.

Black plate (46,1)GMC Sierra Owner Manual - 2011
9-46 Driving and Operating
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 9‑50. 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 9‑41 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
(Continued)

Black plate (59,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-59
Electronic Transfer Case
The transfer case knob is located
next to the steering column.
Use the dial to shift into and out of
four-wheel drive.
Recommended Transfer Case Settings
Driving ConditionsTransfer Case Settings
2m 4m4n N
Normal YES Severe YES
Extreme YES
Vehicle in Tow* YES
*See Recreational Vehicle Towing on page 10‑103 orTowing the Vehicle
on page 10‑103.
You can choose among four driving
settings:
Indicator lights in the dial
show which setting you are in.
The indicator lights will come on
briefly when you turn on the ignition
and one will stay on. If the lights do
not come on, you should take the
vehicle to your dealer for service.
An indicator light flashes while
shifting the transfer case and remains illuminated when the
shift is complete. If for some
reason the transfer case cannot
make a requested shift, it will return
to the last chosen setting.
2
m(Two-Wheel Drive High):
This
setting is used for driving in most
street and highway situations.
The front axle is not engaged in
Two-Wheel Drive. This setting also
provides the best fuel economy.