2012 GMC SIERRA 1500 key

Black plate (29,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-29
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 shift lever 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 way down.
.Turning the ignition switch to the
LOCK/OFF position.
Retained Accessory
Power (RAP)
The following vehicle accessories
can be used for up to 10 minutes
after the engine is turned off:
.Audio System
.Power Windows
.OnStar System (if equipped)
.Sunroof (if equipped)
These features work when
the key is in ON/RUN or ACC/
ACCESSORY. Once the key is
turned from ON/RUN to LOCK/OFF,
the windows and sunroof continue
to work up to 10 minutes until any
door is opened. The radio continues
to work for up to 10 minutes or until
the driver door is opened.

Black plate (31,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-31
WARNING (Continued)
gear—not in N (Neutral). If you
are pulling a trailer, see Driving
Characteristics and Towing Tips
on page 9‑74.
1. Hold the brake pedal down, then set the parking brake.
See Parking Brake on page 9‑54
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).
Leaving the Vehicle With the
Engine Running
{WARNING
It can be dangerous to leave the
vehicle with the engine running.
The vehicle could move suddenly
if the shift lever is not fully in
P (Park) with the parking brake
firmly set.
If you have four-wheel drive and
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).
And, if you leave the vehicle
with the engine running, it could
overheat and even catch fire. You
or others could be injured. Do not
leave the vehicle with the engine
running unless you have to. If you have to leave the vehicle with
the engine running, be sure your
vehicle is in P (Park) and the
parking brake is firmly set before
you leave it. After you move the shift
lever into P (Park), hold the regular
brake pedal down. Then, see if you
can move the shift lever away from
P (Park) without first pulling it toward
you. If you can, it means that the
shift lever was not fully locked into
P (Park).
Torque Lock
If you are parking on a hill and
you do not shift your transmission
into P (Park) properly, the weight
of the vehicle may put too much
force on the parking pawl in the
transmission. You may find it
difficult to pull the shift lever out of
P (Park). This is called torque lock.
To prevent torque lock, set the
parking brake and then shift into
P (Park) properly before you leave
the driver seat. To find out how,
Shifting Into Park on page 9‑30.

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 (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.

Black plate (37,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-37
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. Adaptive shift controls
continually compares key shift
parameters to pre-programmed
ideal shifts stored in the
transmissions computer. The
transmission constantly makes
adjustments to improve vehicle
performance according to how thevehicle is being used, such as with
a heavy load or when 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 Allison Transmission and
Hydra-Matic 6-Speed 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.
M (Manual Mode):
This position
is available on vehicles with
the Allison Transmission or
Hydra-Matic 6-Speed transmission.
It lets drivers select the range of
gears appropriate for current driving
conditions. If the vehicle has this
feature, see “Range Selection
Mode” underManual Mode on
page 9‑38. 3 (Third):
This position is also used
for normal driving. It reduces vehicle
speed more than D (Drive) without
using the brakes. You might choose
3 (Third) instead of D (Drive) when
driving on hilly, winding roads, when
towing a trailer, so there is less
shifting between gears and when
going down a steep hill.
2 (Second): This position reduces
vehicle speed even more than
3 (Third) without using the brakes.
You can use 2 (Second) on hills.
It can help control vehicle speed as
you go down steep mountain roads,
but then you would also want to use
the brakes off and on.
If you manually select 2 (Second) in
an automatic transmission, the
transmission will start in second
gear. You can use this feature for
reducing the speed of the rear
wheels when you are trying to start
the vehicle from a stop on slippery
road surfaces.

Black plate (64,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-64 Driving and Operating
The delay after shifting out of
R (Reverse) is approximately
10 seconds. The delay can be
canceled by performing one of the
following:
.Pressing a hard key on the
navigation system.
.Shifting into P (Park).
.Reaching a vehicle speed of
8 km/h (5 mph).
Adjusting the Brightness and
Contrast of the Screen
To adjust the brightness and
contrast of the screen, press the
MENU button while the RVC image
is on the display. Any adjustments
made will only affect the RVC
screen.
](Brightness): Touch the + (plus)
or –(minus) screen buttons to
increase or decrease the brightness
of the screen.
_(Contrast): Touch the + (plus)
or –(minus) screen buttons to
increase or decrease the contrast of
the screen.
Symbols
The navigation system may have a
feature that allows for viewing
parking assist symbols on the
navigation screen while using the
RVC. The Ultrasonic Rear Park
Assist (URPA) system must not be
disabled to use the caution symbols.
If URPA has been disabled and the
symbols have been turned on,
the Rear Parking Assist Symbols
Unavailable error message may
display. See Ultrasonic Parking
Assist on page 9‑61.
The symbols appear near objects
detected by the URPA system. The
symbol may cover the object when
viewing the navigation screen.
To turn the symbols on or off:
1. Make sure that URPA has not been disabled.
2. Shift into P (Park). 3. Press MENU to enter the
configure menu options. Turn
the Multifunction knob until the
Display feature is highlighted
and press the Multifunction
knob. Or press the Display
screen button
4. Select the Rear Camera Options screen button. The Rear Camera
Options screen displays.
5. Touch the Symbols screen button. The screen button will
be highlighted when on.
Guidelines
The RVC system has a guideline
overlay that can help the driver align
the vehicle when backing into a
parking spot.
If the vehicle has dual rear wheels,
this feature will not be available.
To turn the guidelines on or off:
1. Make sure that URPA has not been disabled.
2. Shift into P (Park).

Black plate (3,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-3
California Proposition
65 Warning
Most motor vehicles, including this
one, contain and/or emit chemicals
known to the State of California to
cause cancer and birth defects or
other reproductive harm. Engine
exhaust, many parts and systems,
many fluids, and some component
wear by-products contain and/or
emit these chemicals.
California Perchlorate
Materials Requirements
Certain types of automotive
applications, such as airbag
initiators, safety belt pretensioners,
and lithium batteries contained in
Remote Keyless Entry transmitters,
may contain perchlorate materials.
Special handling may be necessary.
For additional information, see
www.dtsc.ca.gov/hazardouswaste/
perchlorate.
Accessories and
Modifications
Adding non‐dealer accessories or
making modifications to the vehicle
can affect vehicle performance and
safety, including such things as
airbags, braking, stability, ride and
handling, emissions systems,
aerodynamics, durability, and
electronic systems like antilock
brakes, traction control, and stability
control. These accessories or
modifications could even cause
malfunction or damage not covered
by the vehicle warranty.

Black plate (25,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-25
loading, trailer towing, and/or high
outside temperatures, the fan speed
increases as the clutch more fully
engages, so an increase in fan
noise may be heard. This is normal
and should not be mistaken as the
transmission slipping or making
extra shifts. It is merely the cooling
system functioning properly. The fan
will slow down when additional
cooling is not required and the
clutch disengages.
This fan noise may also be heard
when starting the engine. It will go
away as the fan clutch partially
disengages.
If the vehicle has electric cooling
fans, the fans may be heard
spinning at low speed during most
everyday driving. The fans may
turn off if no cooling is required.
Under heavy vehicle loading, trailer
towing, high outside temperatures,
or operation of the air conditioning
system, the fans may change to
high speed and an increase in fan
noise may be heard. This is normal
and indicates that the coolingsystem is functioning properly. The
fans will change to low speed when
additional cooling is no longer
required.
Power Steering Fluid
See
Engine Compartment Overview
on page 10‑6 for reservoir location.
When to Check Power Steering
Fluid
It is not necessary to regularly
check power steering fluid unless
there is a leak suspected in the
system or an unusual noise is
heard. A fluid loss in this system
could indicate a problem. Have the
system inspected and repaired.
How to Check Power Steering
Fluid
Notice:Extremely small amounts
of contamination can cause
steering system damage and
cause it to not work properly. Do
not allow contaminants to contact
the fluid side of the reservoir cap/
dipstick or to enter the reservoir.
To check the power steering fluid:
1. Turn the key off and let the engine compartment cool down.
2. Wipe the cap and the top of the reservoir clean.
3. Unscrew the cap and wipe the dipstick with a clean rag.
4. Replace the cap and completely tighten it.
5. Remove the cap again and look at the fluid level on the dipstick.
The level should be at the FULL
COLD mark. If necessary, add only
enough fluid to bring the level up to
the mark.