GMC SIERRA 1500 2012 Owners Manual

Black plate (55,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-55
This feature is designed to prevent
the vehicle from rolling, either
forward or rearward, during vehicle
drive off. After the driver completely
stops and holds the vehicle in a
complete standstill on a grade, HSA
will be automatically activated.
During the transition period between
when the driver releases the brake
pedal and starts to accelerate to
drive off on a grade, HSA holds the
braking pressure for a maximum of
two seconds to ensure that there
is no rolling. The brakes will
automatically release when the
accelerator pedal is applied within
the two‐second window. If the
vehicle is equipped with the
Integrated Trailer Brake Control
(ITBC) system, HSA may also apply
the trailer brakes. It will not activate
if the vehicle is in a drive gear and
facing downhill or if the vehicle is
facing uphill and in R (Reverse).
There may be situations on minor
hills (less than 5% grade) with a
loaded vehicle or while pulling a
trailer where HSA will not activate.Ride Control Systems
StabiliTrak®System
The vehicle has a vehicle stability
enhancement system called
StabiliTrak. It is an advanced
computer-controlled system that
assists the driver with directional
control of the vehicle in difficult
driving conditions.
StabiliTrak activates when the
computer senses a discrepancy
between the intended path and the
direction the vehicle is actually
traveling. StabiliTrak selectively
applies braking pressure at any one
of the vehicle's brakes to assist the
driver with keeping the vehicle on
the intended path.
StabiliTrak is on automatically
whenever the vehicle is started. To
assist with directional control of the
vehicle, the system should always
be left on. Trailer Sway Control
(TSC) is also on automatically whenthe vehicle is started. See
Trailer
Sway Control (TSC) on page 9‑105
for more information.
When the vehicle is started and
begins to move, the system
performs several diagnostic checks
to insure there are no problems.
The system may be heard or felt
while it is working. This is normal
and does not mean there is a
problem with the vehicle. The
system should initialize before the
vehicle reaches 32 km/h (20 mph).
In some cases, it may take
approximately 3.2 km (2 mi) of
driving before the system initializes.
If cruise control is being used
when StabiliTrak activates, the
cruise control automatically
disengages. The cruise control
can be re-engaged when road
conditions allow. See Cruise Control
on page 9‑58.
If the system fails to turn on or
activate, the StabiliTrak light along
with a message will be displayed on
the Driver Information Center (DIC).

Black plate (56,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-56 Driving and Operating
If a DIC message appears, make
sure the StabiliTrak system has not
been turned off using the Traction
Control System (TCS)/StabiliTrak
button. Then turn the vehicle off,
wait 15 seconds, and then turn it
back on again to reset the system.
If any of the messages still appear
on the DIC, the vehicle should be
taken in for service. For more
information on the DIC messages,
seeRide Control System Messages
on page 5‑44.
The StabiliTrak light will flash on the
instrument panel cluster when the
system or the TSC feature is both
on and activated.
The system may be heard or felt
while it is working; this is normal.
The TCS/StabiliTrak button is
located on the instrument panel.
The traction control part of
StabiliTrak can be turned off by
pressing and releasing the TCS/
StabiliTrak button if both systems
(traction control and StabiliTrak)
were previously on.
To disable both TCS and
StabiliTrak, press and hold the
TCS/StabiliTrak button until the
StabiliTrak OFF light illuminates and the appropriate DIC message
displays. This will also disable the
TSC feature.
Traction control and StabiliTrak
can be turned on by pressing and
releasing the TCS/StabiliTrak button
if they are not automatically shut off
for any other reason. This will also
enable the TSC feature.
When the TCS or StabiliTrak system
is turned off, the StabiliTrak light
and the appropriate message will be
displayed on the DIC to warn the
driver. The vehicle will still have
brake-traction control when traction
control is off, but will not be able to
use the engine speed management
system. See
“Traction Control
Operation” next for more
information.
When the TCS has been turned off,
system noises may still be heard as
a result of the brake-traction control
coming on.

Black plate (57,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-57
It is recommended to leave the
system on for normal driving
conditions, but it may be necessary
to turn the system off if the vehicle
is stuck in sand, mud, ice or snow,
and you want to“rock”the vehicle to
attempt to free it. It may also be
necessary to turn off the system
when driving in extreme off-road
conditions where high wheel spin is
required. See If the Vehicle Is Stuck
on page 9‑15.
When the transfer case is in 4LO,
the stability system is automatically
disabled, the StabiliTrak light comes
on, and the appropriate message
will appear on the DIC. Both
traction control and StabiliTrak
are automatically disabled in this
condition.
Traction Control Operation
The TCS is part of the StabiliTrak
system. Traction control limits wheel
spin by reducing engine power
to the wheels (engine speed
management) and by applying brakes to each individual wheel
(brake-traction control) as
necessary.
The TCS is enabled automatically
when the vehicle is started. It will
activate and the StabiliTrak light
will flash if it senses that any of the
wheels are spinning or beginning to
lose traction while driving. If traction
control is turned off, only the
brake-traction control portion of
traction control will work. The
engine speed management will be
disabled. In this mode, engine
power is not reduced automatically
and the driven wheels can spin
more freely. This can cause the
brake-traction control to activate
constantly.
Notice:
If the wheel(s) of one axle
is allowed to spin excessively
while the StabiliTrak
®, ABS, brake
warning lights, and any relevant
DIC messages are displayed, the
transfer case could be damaged.
The repairs would not be covered
by the vehicle warranty. Reduce
engine power and do not spin the wheel(s) excessively while these
lights and messages are
displayed.
The TCS may activate on dry or
rough roads or under conditions
such as heavy acceleration while
turning or abrupt upshifts/downshifts
of the transmission. When this
happens, a reduction in acceleration
may be noticed, or a noise or
vibration may be heard. This is
normal.
If cruise control is being used when
the system activates, the StabiliTrak
light will flash and cruise control will
automatically disengage. Cruise
control may be reengaged when
road conditions allow. See
Cruise
Control on page 9‑58.
StabiliTrak may also turn off
automatically if it determines that a
problem exists with the system.
If the problem does not clear itself
after restarting the vehicle, see your
dealer for service.

Black plate (58,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-58 Driving and Operating
Non-hybrid vehicles with StabiliTrak
have a Trailer Sway Control (TSC)
feature. SeeTrailer Sway Control
(TSC) on page 9‑105.
Non-hybrid vehicles with StabiliTrak
have a Hill Start Assist (HSA)
feature. See Hill Start Assist (HSA)
on page 9‑54.
Adding non‐dealer accessories can
affect the vehicle's performance.
See Accessories and Modifications
on page 10‑3.
Locking Rear Axle
Vehicles with a locking rear axle can
give more traction on snow, mud,
ice, sand, or gravel. It works like a
standard axle most of the time, but
when traction is low, this feature will
allow the rear wheel with the most
traction to move the vehicle.
Cruise Control
{WARNING
Cruise control can be dangerous
where you cannot drive safely at
a steady speed. So, do not use
the cruise control on winding
roads or in heavy traffic.
Cruise control can be dangerous
on slippery roads. On such roads,
fast changes in tire traction can
cause excessive wheel slip, and
you could lose control. Do not use
cruise control on slippery roads.
For vehicles with cruise control, a
speed of about 40 km/h (25 mph)
or more can be maintained
without keeping your foot on the
accelerator. Cruise control does not
work at speeds below about 40 km/h
(25 mph). When the brakes are applied, cruise
control is turned off.
For vehicles with an Allison or
Hydra‐Matic 6‐speed automatic
transmission, see
“Grade Braking”
under Tow/Haul Mode on page 9‑39
for an explanation of how cruise
control interacts with the Range
Selection Mode, tow/haul and grade
braking systems.
For vehicles with the StabiliTrak
system that begins to limit wheel
spin while you are using cruise
control, the cruise control will
automatically disengage. See
StabiliTrak
®System on page 9‑55.
When road conditions allow the
cruise control to be safely used
again, it can be turned back on.

Black plate (59,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-59
I(On/Off):Press to turn the
system on or off. The indicator light
is on when cruise control is on and
turns off when cruise control is off.
+ RES (Resume/Accelerate):
Press briefly to resume to a
previously set speed, or press and
hold to accelerate.
SET −(Set/Coast): Press to set
the speed and activate cruise
control or make the vehicle
decelerate.
[(Cancel): Press to disengage
cruise control without erasing the
set speed from memory.
Setting Cruise Control
If the cruise button is on when not in
use, it could get bumped and go into
cruise when not desired. Keep the
cruise control switch off when cruise
is not being used.
The cruise control light on the
instrument panel cluster will come
on after the cruise control has been
set to the desired speed.
1. Press
I.
2. Get up to the desired speed.
3. Press the SET− button located
on the steering wheel and
release it.
4. Take your foot off the accelerator. Resuming a Set Speed
If the cruise control is set at a
desired speed and then the brakes
are applied, the cruise control is
disengaged without erasing the set
speed from memory.
Once the vehicle speed reaches
about 40 km/h (25 mph) or more,
press the +RES button on the
steering wheel. The vehicle returns
to the previous set speed and stays
there.
Increasing Speed While Using
Cruise Control
If the cruise control system is
already activated,
.Press and hold the +RES button
on the steering wheel until the
desired speed is reached, then
release it.
.To increase vehicle speed in
small amounts, press the
+RES button. Each time this is
done, the vehicle goes about
1.6 km/h (1 mph) faster.

Black plate (60,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-60 Driving and Operating
Reducing Speed While Using
Cruise Control
If the cruise control system is
already activated,
.Press and hold the SET–button
on the steering wheel until the
desired lower speed is reached,
then release it.
.To slow down in small amounts,
press the SET– button on the
steering wheel briefly. Each time
this is done, the vehicle goes
about 1.6 km/h (1 mph) slower.
Passing Another Vehicle While
Using Cruise Control
Use the accelerator pedal to
increase the vehicle speed. When
you take your foot off the pedal,
the vehicle will slow down to the
previous set cruise speed.
Using Cruise Control on Hills
How well the cruise control works
on hills depends on the vehicle
speed, the load, and the steepness
of the hills. When going up steep hills, pressing the accelerator pedal
may be necessary to maintain
vehicle speed.
While going downhill:
.Vehicles with a four speed
automatic transmission may
need to have the brakes applied
or the transmission shifted
to a lower gear to keep the
speed down.
.Vehicles with a six speed
automatic transmission have a
Cruise Grade Braking feature
that may automatically shift to a
lower gear to keep the speed
down. It may be necessary to
apply the brake or manually
shift the transmission to a lower
gear. The vehicle may shift to a
higher gear when grade braking
assistance is no longer required.
Cruise Grade Braking is not
available while in Range
Selection Mode. This feature is
active when the exhaust brake
is enabled (if equipped). See
"Range Selection Mode" under
Manual Mode on page 9‑38.
When the brakes are manually
applied the cruise control is
disengaged.
Ending Cruise Control
There are three ways to end cruise
control:.To disengage cruise control;
step lightly on the brake pedal.
.Press[on the steering wheel.
.To turn off the cruise control,
press
Ion the steering wheel.
Erasing Speed Memory
The cruise control set speed
is erased from memory by
pressing
Ior if the ignition is
turned off.

Black plate (61,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-61
Object Detection
Systems
Ultrasonic Parking Assist
If available, the Ultrasonic Rear
Parking Assist (URPA) system
assists the driver with parking
and avoiding objects while in
R (Reverse). URPA operates at
speeds less than 8 km/h (5 mph).
The sensors on the rear bumper
detect objects up to 2.5 m (8 ft)
behind the vehicle, and at least
25 cm (10 in) off the ground.
{WARNING
The URPA system does not
detect pedestrians, bicyclists,
animals, or objects below the
bumper or that are too close or
too far from the vehicle. To
prevent injury, death, or vehicle
damage, even with URPA, always(Continued)
WARNING (Continued)
check the area around the vehicle
and check all mirrors before
backing.
How the System Works
URPA comes on automatically
when the shift lever is moved into
R (Reverse). A single tone sounds
to indicate the system is working.
URPA operates only at speeds less
than 8 km/h (5 mph).
An obstacle is indicated by audible
beeps. The interval between the
beeps becomes shorter as the
vehicle gets closer to the obstacle.
When the distance is less than
30 cm (12 in) the beeping is a
continuous tone for five seconds.
To be detected, objects must be at
least 25 cm (10 in) off the ground
and below tailgate level. Objects
must also be within 2.5 m (8 ft) from the rear bumper. This distance may
be less during warmer or humid
weather.
Turning the System On and Off
The URPA system can be turned
on and off using the rear park aid
disable button located next to the
radio.
The indicator light comes on when
the system is disabled and turns off
when the system is on.
When the system is off, PARK
ASSIST OFF displays on the Driver
Information Center (DIC). The
message disappears after a short
period of time.

Black plate (62,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-62 Driving and Operating
URPA defaults to the on setting
each time the vehicle is started.
Notice:If you use URPA while the
tailgate is lowered, it may not
detect an object behind your
vehicle, and you might back into
the object and damage your
vehicle. Always verify the tailgate
is closed when using URPA or
turn off URPA when driving with
the tailgate lowered.
When the System Does Not
Seem to Work Properly
The following messages may be
displayed on the DIC:
SERVICE PARK ASSIST: If this
message occurs, take the vehicle to
your dealer to repair the system. PARK ASST BLOCKED SEE
OWNERS MANUAL:
This
message can occur under the
following conditions:
.The ultrasonic sensors are not
clean. Keep the vehicle's rear
bumper free of mud, dirt, snow,
ice, and slush. For cleaning
instructions, see Exterior Care
on page 10‑98.
.The park assist sensors are
covered by frost or ice. Frost or
ice can form around and behind
the sensors and may not always
be seen; this can occur after
washing the vehicle in cold
weather. The message may not
clear until the frost or ice has
melted.
.A trailer was attached to the
vehicle, or an object was
hanging out of the tailgate during
the last drive cycle. Once the
object is removed and the
tailgate is raised, URPA will
return to normal operation.
.A tow bar is attached to the
vehicle.
.The bumper is damaged. Take
the vehicle to your dealer to
repair the system.
.Other conditions, such as
vibrations from a jackhammer or
the compression of air brakes on
a very large truck, are affecting
system performance.
Rear Vision
Camera (RVC)
If available, the Rear Vision Camera
(RVC) system displays part of the
scene behind the vehicle.
{WARNING
The RVC system does not display
pedestrians, bicyclists, animals,
or any other object located
outside the camera's field of view,
below the bumper, or under the
vehicle. Do not back the vehicle
(Continued)

Black plate (63,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-63
WARNING (Continued)
using only the RVC screen, such
as during longer, higher speed
backing maneuvers, or where
there could be cross-traffic.
Perceived distances may be
different from actual distances.
Failure to use proper care before
backing may result in injury,
death, or vehicle damage. Always
check behind and around the
vehicle before backing.
Vehicles without Navigation
System
The RVC system displays a view of
the area behind the vehicle. When
the vehicle is on and shifted into
R (Reverse) the video image
appears on the inside rearview
mirror. The video image disappears
after the vehicle is shifted out of
R (Reverse).Turning the RVC System On or Off
To turn off the RVC system, press
and hold
z, located on the
inside rearview mirror, until the left
indicator light turns off. The RVC
display is now disabled.
To turn the RVC system on, press
and hold
zuntil the left indicator
light comes on. The RVC system
display will appear in the mirror.
Vehicles with Navigation
System
The RVC system is designed to
help the driver when backing up by
displaying a view of the area behind
the vehicle. When the vehicle is
shifted into R (Reverse), the video
image appears on the navigation
screen. After a delay, the navigation
screen displays the last screen after
the vehicle is shifted out of
R (Reverse). Turning the RVC System On or Off
To turn the RVC system on or off:
1. Shift into P (Park).
2. 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
3. Select the Rear Camera Options screen button. The Rear Camera
Options screen displays.
4. Select the Video screen button.When the Video screen button
is highlighted the RVC
system is on.

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).