2011 GMC SIERRA light

Black plate (68,1)GMC Sierra Owner Manual - 2011
9-68 Driving and Operating
Brakes
Antilock Brake
System (ABS)
This vehicle has the Antilock
Brake System (ABS), an advanced
electronic braking system that helps
prevent a braking skid.
When the engine is started and the
vehicle begins to drive away, ABS
checks itself. A momentary motor
or clicking noise might be heard
while this test is going on, and
it might even be noticed that
the brake pedal moves a little.
This is normal.If there is a problem with ABS, this
warning light stays on. SeeAntilock
Brake System (ABS) Warning Light
on page 5‑28.
If driving safely on a wet road
and it becomes necessary to
slam on the brakes and continue
braking to avoid a sudden obstacle,
a computer senses that the wheels
are slowing down. If one of the
wheels is about to stop rolling,
the computer will separately
work the brakes at each wheel.
ABS can change the brake pressure
to each wheel, as required, faster
than any driver could. This can help
the driver steer around the obstacle
while braking hard. As the brakes are applied, the
computer keeps receiving updates
on wheel speed and controls
braking pressure accordingly.
Remember: ABS does not change
the time needed to get a foot up to
the brake pedal or always decrease
stopping distance. If you get too
close to the vehicle in front of you,
there will not be enough time to
apply the brakes if that vehicle
suddenly slows or stops. Always
leave enough room up ahead to
stop, even with ABS.
Using ABS
Do not pump the brakes. Just hold
the brake pedal down firmly and let
ABS work. You might hear the ABS
pump or motor operating and feel
the brake pedal pulsate, but this is
normal.

Black plate (69,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-69
Braking in Emergencies
ABS allows the driver to steer and
brake at the same time. In many
emergencies, steering can help
more than even the very best
braking.
Parking Brake
Set the parking brake by holding
the regular brake pedal down, then
pushing down the parking brake
pedal.If the ignition is on, the brake
system warning light will come on.
See
Brake System Warning Light on
page 5‑27.
Notice: Driving with the parking
brake on can overheat the brake
system and cause premature
wear or damage to brake system
parts. Make sure that the parking
brake is fully released and the
brake warning light is off before
driving.
To release the parking brake, hold
the regular brake pedal down, then
push down momentarily on the
parking brake pedal until you feel
the pedal release. Slowly pull your
foot up off the parking brake pedal.
If the parking brake is not released
when you begin to drive, the brake
system warning light will flash and a
chime will sound warning you that
the parking brake is still on.
If you are towing a trailer and
are parking on a hill, see Driving
Characteristics and Towing Tips on
page 9‑91.
Brake Assist (Except
With 4.3L V6 Engine)
If this vehicle has StabiliTrak®, it
also has a Brake Assist feature
designed to assist the driver in
stopping or decreasing vehicle
speed in emergency driving
conditions. This feature uses the
stability system hydraulic brake
control module to supplement
the power brake system under
conditions where the driver has
quickly and forcefully applied the
brake pedal in an attempt to quickly
stop or slow down the vehicle.
The stability system hydraulic brake
control module increases brake
pressure at each corner of the
vehicle until the ABS activates.

Black plate (71,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-71
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. SeeCruise Control on
page 9‑73 for more information.
If the system fails to turn on or
activate, the StabiliTrak light
along with one of the following
messages will be displayed
on the Driver Information
Center (DIC): TRACTION CONTROL OFF, SERVICE
TRACTION CONTROL,
STABILITRAK OFF, SERVICE
STABILITRAK. If these DIC
messages appear, make sure the
StabiliTrak system has not been
turned off using the StabiliTrak
on/off button. Then turn the vehicle
off, wait 15 seconds, and turn it
back on again to reset the system.
If any of these messages still
appear on the DIC, the vehicle
should be taken in for service.
For more information on the DIC
messages, see
Ride Control
System Messages on page 5‑47.
The StabiliTrak light will flash on the
instrument panel cluster when the
system is both on and activated. The system may be heard or felt
while it is working; this is normal.
The traction control disable button
is located on the instrument panel
below the climate controls.
The Traction Control System (TCS)
part of StabiliTrak can be turned
off by pressing and releasing the
StabiliTrak button. To disable both
TCS and StabiliTrak, press and
hold
5untilFilluminates and the
appropriate DIC message displays.
TCS and StabiliTrak can be turned
on by pressing and releasing the
StabiliTrak button if they are not
automatically shut off for any other
reason.

Black plate (72,1)GMC Sierra Owner Manual - 2011
9-72 Driving and Operating
When TCS or StabiliTrak 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 traction control system
has been turned off, system noises
may still be heard as a result of the
brake-traction control coming on.
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 9‑23. When the transfer case is in 4LO,
the stability system is automatically
disabled, the StabiliTrak light comes
on, and the STABILITRAK OFF
message will appear on the DIC.
Both traction control and StabiliTrak
are automatically disabled in this
condition.
Traction Control Operation
The traction control system 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 traction control system 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.

Black plate (73,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-73
The traction control system 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. SeeCruise
Control on page 9‑73.
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. 2500 and 3500 series vehicles
with StabiliTrak have a Trailer Sway
Control (TSC) feature. See
Trailer
Sway Control (TSC) on page 9‑124.
2500 and 3500 series vehicles
with StabiliTrak have a Hill Start
Assist (HSA) feature. See Hill Start
Assist (HSA) on page 9‑70.
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).

Black plate (74,1)GMC Sierra Owner Manual - 2011
9-74 Driving and Operating
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
and Cruise Grade Braking
(Allison Transmission) under
Tow/Haul Mode on page 9‑51
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 9‑70.
When road conditions allow the
cruise control to be safely used
again, it can be turned back on.
The cruise control buttons are
located on the left side of the
steering wheel.
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.

Black plate (76,1)GMC Sierra Owner Manual - 2011
9-76 Driving and Operating
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
the
Ibutton or if the ignition is
turned off.
Object Detection
Systems
Ultrasonic Parking Assist
For vehicles with the Ultrasonic
Rear Parking Assist (URPA) system,
it operates at speeds less than
8 km/h (5 mph), and assists the
driver with parking and avoiding
objects while in R (Reverse).
The sensors on the rear bumper
are used to detect the distance to
an object up to 2.5 m (8 ft) behind
the vehicle, and at least 25.4 cm
(10 in) off the ground.
{WARNING
The Ultrasonic Rear Parking
Assist (URPA) system does not
replace driver vision. It cannot
detect:
.Objects that are below the
bumper, underneath the
vehicle, or too close or far
from the vehicle.
.Children, pedestrians,
bicyclists, or pets.
If you do not use proper care
before and while backing, vehicle
damage, injury, or death could
occur. Even with URPA, always
check behind the vehicle before
backing up. While backing, be
sure to look for objects and check
the vehicle's mirrors.

Black plate (77,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-77
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 beeps are
continuous.
To be detected, objects must be at
least 25.4 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.
The system can be disabled by
pressing the rear park aid disable
button located next to the radio.
The indicator light comes on and
PARK ASSIST OFF displays on the
Driver Information Center (DIC) to
indicate that URPA is off; seeObject
Detection System Messages on
page 5‑46.
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 ASSIST OFF: This message
occurs if the driver disables 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 “Washing the
Vehicle” underExterior Care on
page 10‑108.