MANUAL MODE (M): This position lets drivers select
the range of gears appropriate for current driving
conditions. See Driver Shift Control (DSC) later in this
section.
Notice: Spinning the tires or holding the vehicle in
one place on a hill using only the accelerator
pedal may damage the transmission. The repair will
not be covered by your warranty. If you are stuck,
do not spin the tires. When stopping on a hill,
use the brakes to hold the vehicle in place.
Your 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
will be 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 may appear to be
a delayed shift, however the transmission is operating
normally. Your vehicle’s transmission uses adaptive shift controls
that 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
the vehicle is being used, such as with a heavy load or
when temperature changes. During this adaptive
shift controls process, shifting may feel different as the
transmission determines the best settings.
When temperatures are very cold, the Hydra-Matic ®
6L80 automatic transmission’s gear shifting may
be delayed providing more stable shifts until the engine
warms up. Shifts may be more noticeable with a cold
transmission. This difference in shifting is normal.
2-32
Tow/Haul Mode
Your vehicle has a tow/haul mode. The tow/haul mode
adjusts the transmission shift pattern to reduce shift
cycling, providing increased performance, vehicle
control, and transmission cooling when towing or hauling
heavy loads.
Press the button located on the end of the shift lever to
turn the tow/haul on or off. When the tow/haul is on,
a light on the instrument panel cluster will come on.
See Tow/Haul Mode Light on page 3-47 for more
information. Also see “Tow Haul Mode” under Towing a Trailer on
page 4-44 for more information.
The tow/haul mode works with the Autoride ®
feature, if
the vehicle has this, to enhance the ride when
trailering or with a loaded vehicle. See Autoride ®
on
page 4-43 .
Grade Braking Grade Braking assists when driving on a downhill grade.
It maintains the vehicle’s speed by automatically
implementing a shift schedule that uses the engine and
the transmission to slow the vehicle. This reduces
wear on the brakes system and increases control of the
vehicle. The system constantly monitors the vehicle’s
speed, acceleration, throttle position, and whether
the brake pedal is being pressed, and determines when
to keep the current vehicle speed or to slow down.
The system will then automatically command downshifts
that reduces the vehicles speed, until the brake pedal
is no longer being pressed. This indicates the desired
vehicle speed has been reached.
The tow/haul mode and grade braking shift modes can
be activated by pressing the button on the end of
the shift control stalk. While in the DSC mode, grade
braking is deactivated, allowing the driver to select
a gear.
See Automatic Transmission Operation on page 2-30 for
more information.
2-34
When the System Does Not Seem to
Work Properly The driver disables the system.
The parking brake pedal is depressed.
The ultrasonic sensors are not clean. Keep your
vehicle’s rear bumper free of mud, dirt, snow,
ice and slush. For cleaning instructions, see
Washing Your Vehicle on page 5-102 .
A trailer was attached to your vehicle, or a bicycle
or an object was hanging out of your liftgate/liftglass
during your last drive cycle, the red light may
illuminate in the rear display. Once the attached
object is removed, URPA will return to normal
operation.
A tow bar is attached to your vehicle.
The vehicle’s bumper is damaged. Take the vehicle
to your dealer/retailer to repair the system.
Other conditions may affect system performance,
such as vibrations from a jackhammer or the
compression of air brakes on a very large truck.
If the system is still disabled, after driving forward at
least 15 mph (25 km/h), take your vehicle to your
dealer/retailer. OnStar ®
System OnStar uses several innovative technologies and live
advisors to provide you with a wide range of safety,
security, information, and convenience services. If your
airbags deploy, the system is designed to make an
automatic call to OnStar Emergency advisors who can
request emergency services be sent to your location.
If you lock your keys in the vehicle, call OnStar at
1-888-4-ONSTAR and they can send a signal to unlock
your doors. If you need roadside assistance, press
the OnStar button and they can contact Roadside
Service for you.
2-50
Cruise Control
{ CAUTION: Cruise control can be dangerous where you
cannot drive safely at a steady speed. So, do
not use your 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.
With cruise control, you can maintain a speed of about
25 mph (40 km/h) or more without keeping your foot
on the accelerator. This can really help on long
trips. Cruise control does not work at speeds below
about 25 mph (40 km/h).
When you apply your brakes, cruise control is turned off.
If your vehicle has the StabiliTrak ®
system and begins
to limit wheel spin while you are using cruise control, the
cruise control will automatically disengage. See
StabiliTrak ®
System on page 4-6 . When road conditions
allow you to safely use it again, you may turn the
cruise control back on. The cruise control buttons
are located on left side of
the steering wheel.
T (On/Off): This button can both activate and turn
off the system. The indicator light on the button turns on
when cruise control is on and turns off when cruise
control is off.
+ RES (Resume/Accelerate): Press this button to
make the vehicle accelerate or resume to a previously
set speed.
SET − (Set/Coast): Press this button to set the speed
or make the vehicle decelerate.
[ (Cancel): Press this button to cancel cruise control
without erasing the set speed from memory.
3-13
Brake System Warning Light With the ignition on, the brake system warning light will
come on when you set the parking brake. If you try
to drive with the parking brake engaged, a chime will
sound when the vehicle speed is greater than 3 mph
(5 km/h).
Your vehicle’s hydraulic brake system is divided into two
parts. If one part is not working, the other part can
still work and stop you. For good braking, though, you
need both parts working well.
If the warning light comes on and a chime sounds there
could be a brake problem. Have your brake system
inspected right away.
This light may also come on due to low brake uid. See
Brakes on page 5-36 for more information. This light should come on brie y when you turn the
ignition key to RUN. If it does not come on then, have it
xed so it will be ready to warn you if there is a
problem.
If the light comes on while you are driving, pull off the
road and stop carefully. You may notice that the pedal is
harder to push or may go closer to the oor. It may
take longer to stop. If the light is still on, have the vehicle
towed for service. See Towing Your Vehicle on
page 4-41 .
{ CAUTION: Your brake system may not be working
properly if the brake system warning light is
on. Driving with the brake system warning light
on can lead to an accident. If the light is still
on after you have pulled off the road and
stopped carefully, have the vehicle towed for
service.
United States
Canada
3-40