2009 GMC SIERRA 1500 brakes

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 the vehicle 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 Select Mode
(Allison Transmission
®or Hydra-Matic®6-Speed
transmission) later in this section.
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.
2-31

1 (First):For the Hydra-Matic®4-Speed transmission
this position reduces vehicle speed even more than
2 (Second) without using the brakes. You can use it on
very steep hills, or in deep snow or mud. If the shift
lever is put in 1 (First) while the vehicle is moving
forward, the transmission does not shift into rst gear
until the vehicle is going slowly enough.
For an Allison Transmission
®or Hydra-Matic®6-Speed
transmission, this position reduces vehicle speed
without using the brakes. You can use it for
major/severe downgrades and off-road driving where
the vehicle would otherwise accelerate due to steepness
of grade. When you shift to 1 (First) it provides the
lowest gear appropriate to current road speed and
continues to downshift as the vehicle slows, eventually
downshifting to 1 (First) gear.
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 the vehicle warranty. If you
are stuck, do not spin the tires. When stopping on
a hill, use the brakes to hold the vehicle in place.
Range Selection Mode (Allison®or
Hydra-Matic®6-Speed Transmission)
The vehicle may have a Range Selection Mode.
The Range Selection Mode helps control the vehicle’s
transmission and vehicle speed while driving down hill
or towing a trailer by letting you select a desired range
of gears.
2-32

To use this feature, do the following:
1. Move the shift lever to M (Manual Mode).
2. Press the plus/minus buttons, located on the
steering column shift lever, to select the desired
range of gears for current driving conditions.
When M (Manual Mode) is selected a number displays
next to the M, indicating the current gear.
This number is the highest gear that can be used.
However, the vehicle can automatically shift to lower
gears as it adjusts to driving conditions. This means
that all gears below that number are available.
When 5 (Fifth) is selected, 1 (First) through 5 (Fifth)
gears are automatically shifted by the vehicle, but
6 (Sixth) cannot be used until the plus/minus button
located on the steering column lever is used to change
to the gear.
Grade Braking is not available when Range Selection
Mode is active. SeeTow/Haul Mode on page 2-34.While using Range Selection Mode, cruise control and
the Tow/Haul mode can be used.
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 the vehicle warranty. If you
are stuck, do not spin the tires. When stopping on a
hill, use the brakes to hold the vehicle in place.
Low Traction Mode
If your vehicle has the Allison Transmission®,orthe
Hydra-Matic®6-Speed Automatic Transmission,
it has a Low Traction Mode that can assist in vehicle
acceleration when road conditions are slippery, such as
with ice or snow. While the vehicle is at a stop, select
the second gear range using Range Selection Mode.
This will limit torque to the wheels after it detects wheel
slip, preventing the tires from spinning.
2-33

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
If the URPA system will not activate due to a temporary
condition, the message PARK ASSIST OFF will be
displayed on the DIC and a red light will be shown on
the rear URPA display when the shift lever is moved into
R (Reverse). This occurs under the following conditions:
The driver disables the system.
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 Your Vehicle on page 5-118.
A trailer was attached to the vehicle, or a bicycle or
an object was hanging out of the tailgate during the
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 the 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 the vehicle to your
dealer/retailer.
2-63

With cruise control, a speed of about 25 mph (40 km/h)
or more can be maintained without keeping your foot
on the accelerator. Cruise control does not work
at speeds below about 25 mph (40 km/h).
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) underTow/Haul
Mode on page 2-34for 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 4-6. 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 left side of
the steering wheel.
T(On/Off):Turns 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 to make the
vehicle accelerate or resume to a previously set speed.
SET−(Set/Coast):Press to set the speed or make
the vehicle decelerate.
[(Cancel):Press to cancel cruise control without
erasing the set speed from memory.
3-13

Setting Cruise Control
Cruise control will not work if the parking brake is set, or
if the master cylinder brake uid level is low.
The cruise control light on the instrument panel cluster
will come on after the cruise control has been set to
the desired speed.
{CAUTION:
If you leave your cruise control on when you are not
using cruise, you might hit a button and go into
cruise when you do not want to. You could be
startled and even lose control. Keep the cruise
control switch off until you want to use cruise
control.
1. Press
T.
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 brakes are applied while the cruise control is set,
the cruise control is disengaged. But it does not need to
be reset.
Once the vehicle speed reaches about 25 mph (40 km/h)
or more, press the +RES button on the steering wheel.
The vehicle will go back to the previous set speed and
stay there.
Increasing Speed While Using Cruise
Control
To increase the cruise speed while using cruise control:
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 increments,
press the +RES button. Each time this is done,
the vehicle goes about 1 mph (1.6 km/h) faster.
3-14

Reducing Speed While Using Cruise
Control
To reduce the vehicle speed while using cruise control:
Press and hold the SET– button on the steering
wheel until the desired lower speed is reached,
then release it.
To slow down in very small amounts, press the
SET– button on the steering wheel briey. Each
time this is done, the vehicle goes about 1 mph
(1.6 km/h) 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 will work on hills depends
upon the vehicle speed, load, and the steepness of the
hills. While going up steep hills, you might have to step on
the accelerator pedal to maintain the vehicle’s speed.
While going downhill, you might have to brake or shift to a
lower gear to keep the vehicle’s speed down. When the
brakes are applied the cruise control turns off.
Ending Cruise Control
There are three ways to end cruise control:
Step lightly on the brake pedal.
Press[on the steering wheel.
PressTon the steering wheel.
Erasing Speed Memory
The cruise control set speed memory is erased, when
the cruise control or the ignition is turned off.
3-15

Readings outside the normal operating range can also
occur when a large number of electrical accessories are
operating in the vehicle and the engine is left idling for an
extended period. This condition is normal since the
charging system is not able to provide full power at
engine idle. As engine speeds are increased, this
condition should correct itself as higher engine speeds
allow the charging system to create maximum power.
The vehicle can only be driven for a short time with the
readings outside the normal operating range. If the
vehicle must be driven, turn off all accessories, such as
the radio and air conditioner.
Readings outside the normal operating range indicate a
possible problem in the electrical system. Have the
vehicle serviced as soon as possible.Brake System Warning Light
With the ignition on, the brake system warning light
comes on when the parking brake is set. If the vehicle is
driven with the parking brake engaged, a chime sounds
when the vehicle speed is greater than 5 mph (8 km/h).
The vehicle’s hydraulic brake system is divided into two
parts. If one part is not working, the other part can still
work and stop the vehicle. For good braking, both parts
need to be working well.
If the warning light comes on and a chime sounds there
could be a brake problem. Have the brake system
inspected right away.
This light can also come on due to low brake uid. See
Brakes on page 5-41for more information.
United States
Canada
3-42