brake HUMMER H3 2009 Owner's Guide

And, of course, actual stopping
distances vary greatly with the
surface of the road, whether it is
pavement or gravel; the condition of
the road, whether it is wet, dry, or
icy; tire tread; the condition of
the brakes; the weight of the vehicle;
and the amount of brake force
applied.
Avoid needless heavy
braking. Some people drive in
spurts — heavy acceleration
followed by heavy braking — rather
than keeping pace with traffic.
This is a mistake. The brakes might
not have time to cool between
hard stops. The brakes will wear out
much faster with a lot of heavy
braking. Keeping pace with
the traffic and allowing realistic
following distances eliminates a lot
of unnecessary braking. That
means better braking and longer
brake life.
If the vehicle ever loses electrical
power while it is being driven, brake
normally but do not pump the
brakes. If the brakes are pumped,the pedal could get harder to push
down. If the vehicle loses electrical
power, there will still be some
power brake assist but it will be
used when the brake is applied.
Once the power assist is used up, it
can take longer to stop, the brake
pedal will be harder to push,
and you might experience longer
pedal travel.
Adding non-dealer/non-retailer
accessories can affect vehicle
performance. SeeAccessories and
Modifications on page 5-3.
Hill Start Assist
This vehicle has a Hill Start Assist
(HSA) feature, which may be
useful when the vehicle is stopped
on a grade. This feature is
designed to prevent the vehicle from
rolling, either forward or rearward,
during vehicle drive off. After
the vehicle is stopped on an incline,
push the brake pedal completely
to the oor to activate Hill StartAssist. When the system activates,
a chime will sound and the HSA
ON message will be displayed.
Letting off the brake pedal slightly or
applying the accelerator pedal to
disengage Hill Start Assist gives the
driver two seconds to pull forward
or back up before the vehicle
starts to roll. Lightly ease off the
brake pedal to disengage Hill
Start Assist. The brakes will
automatically be held for a maximum
of two seconds while the driver
switches from applying the brakes
to pushing the accelerator pedal.
When Hill Start Assist is active, the
driver might experience a “hard
pedal.” This is normal and does not
affect safe brake operation.
On steeper hills, Hill Start Assist will
only activate if the driver tries to
move the vehicle up the hill. 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).
4-4 Driving Your Vehicle

Antilock Brake
System (ABS)
This vehicle has the Antilock Brake
System (ABS), an advanced
electronic braking system that will
help 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.
This is normal.
If there is a problem with ABS, this
warning light stays on. See
Antilock Brake System (ABS)
Warning Light on page 3-28.Let us say the road is wet and you
are driving safely. Suddenly, an
animal jumps out in front of you. You
slam on the brakes and continue
braking. Here is what happens
with ABS:
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 rmly and
let antilock work. The brakes might
vibrate or some noise might be
heard, but this is normal.
Driving Your Vehicle 4-5

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.
Brake Assist
This vehicle 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. Minor brake pedal
pulsations or pedal movement
during this time is normal and the
driver should continue to applythe brake pedal as the driving
situation dictates The Brake Assist
feature will automatically disengage
when the brake pedal is released
or brake pedal pressure is quickly
decreased.
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.
When the vehicle is started and
begins to move, the system
performs several diagnostic checksto 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.
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 3-9.
If there is a problem detected with
StabiliTrak, a SERVICE STAB
SYS message displays on the Driver
Information Center (DIC). See
DIC Warnings and Messages on
page 3-37for more information.
When this message is displayed, the
system is not working. Adjust your
driving accordingly.
StabiliTrak comes on automatically
whenever the vehicle is started
and resets itself at each ignition
cycle. However, when the transfer
case is placed in Four-Wheel-Low
Lock mode, StabiliTrak is
4-6 Driving Your Vehicle

automatically disabled. See
Full-Time Four-Wheel Drive on
page 2-24for more information. 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 it is
necessary to “rock” the vehicle to
attempt to free it. SeeIf Your
Vehicle is Stuck in Sand, Mud, Ice,
or Snow on page 4-33.
To turn the system off, press and
hold the TCS/StabiliTrak button until
the traction off light comes on.
This light comes on steady when
TCS has been turned off. This light
ashes when StabiliTrak is active.To Turn off TCS and StabiliTrak,
press and hold the TCS/StabiliTrak
button until the STAB SYS OFF
message displays on the DIC. Press
and release the TCS/StabiliTrak
button again to turn StabiliTrak
back on. See “Traction Control
System (TCS)”, following, for more
information on turning TCS off
and on.
Traction Control
System (TCS)
The vehicle has a Traction Control
System (TCS) that limits wheel
spin. This is especially useful
in slippery road conditions. The
system operates only if it senses
that any of the wheels are spinning
or beginning to lose traction.
When this happens, TCS reduces
engine power. 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.TCS can operate on dry roads
under some conditions. When this
happens, the system may be
heard working or a reduction in
acceleration may be noticed. This is
normal and does not mean there
is a problem with the vehicle.
Examples of these conditions
include hard acceleration in a turn,
an abrupt upshift or downshift of
the transmission or driving on rough
roads.
If cruise control is being used when
TCS begins to limit wheel spin,
the cruise control automatically
disengages. The cruise control
can be re-engaged when road
conditions allow. SeeCruise Control
on page 3-9for more information.
TRACTION FAULT appears on
the Driver information Center (DIC)
when a TCS or antilock brake
system problem has been detected
and the vehicle needs service.
When this message is on, the
system will not limit wheel spin.
Driving Your Vehicle 4-7

Steering in Emergencies
There are times when steering can
be more effective than braking.
For example, you come over a hill
and nd a truck stopped in your
lane, or a car suddenly pulls
out from nowhere, or a child darts
out from between parked cars
and stops right in front of you. These
problems can be avoided by
braking — if you can stop in time.
But sometimes you cannot stop
in time because there is no room.
That is the time for evasive
action —steering around the
problem.
The vehicle can perform very well in
emergencies like these. First
apply the brakes. SeeBraking on
page 4-3. It is better to remove
as much speed as possible from a
collision. Then steer around the
problem, to the left or right
depending on the space available.An emergency like this requires
close attention and a quick decision.
If holding the steering wheel at
the recommended 9 and 3 o’clock
positions, it can be turned a full
180 degrees very quickly without
removing either hand. But you have
to act fast, steer quickly, and just
as quickly straighten the wheel once
you have avoided the object.
The fact that such emergency
situations are always possible is a
good reason to practice defensive
driving at all times and wear
safety belts properly.
Off-Road Recovery
The vehicle’s right wheels can drop
off the edge of a road onto the
shoulder while driving.
If the level of the shoulder is only
slightly below the pavement,
recovery should be fairly easy. Ease
off the accelerator and then, if
there is nothing in the way, steer
so that the vehicle straddles
the edge of the pavement.
Driving Your Vehicle 4-11

Turn the steering wheel 3 to
5 inches, 8 to 13 cm, (about
one-eighth turn) until the right front
tire contacts the pavement edge.
Then turn the steering wheel to go
straight down the roadway.
Passing
Passing another vehicle on a
two-lane road can be dangerous. To
reduce the risk of danger while
passing:
Look down the road, to the sides,
and to crossroads for situations
that might affect a successful
pass. If in doubt, wait.
Watch for traffic signs,
pavement markings, and lines
that could indicate a turn or
an intersection. Never cross a
solid or double-solid line on your
side of the lane.
Do not get too close to the
vehicle you want to pass. Doing
so can reduce your visibility.
Wait your turn to pass a slow
vehicle.
When you are being passed,
ease to the right.
Loss of Control
Let us review what driving experts
say about what happens when
the three control systems — brakes,
steering, and acceleration — do
not have enough friction where the
tires meet the road to do what
the driver has asked.
In any emergency, do not give up.
Keep trying to steer and constantly
seek an escape route or area of
less danger.
Skidding
In a skid, a driver can lose control
of the vehicle. Defensive drivers
avoid most skids by taking
reasonable care suited to existing
conditions, and by not overdriving
those conditions. But skids are
always possible.The three types of skids
correspond to the vehicle’s three
control systems. In the braking
skid, the wheels are not rolling. In
the steering or cornering skid,
too much speed or steering in a
curve causes tires to slip and
lose cornering force. And in the
acceleration skid, too much
throttle causes the driving wheels
to spin.
Remember: Any traction control
system helps avoid only the
acceleration skid. If the traction
system is off, then an acceleration
skid is best handled by easing
your foot off the accelerator pedal.
SeeTraction Control System
(TCS) on page 4-7andStabiliTrak
®
System on page 4-6.
If the vehicle starts to slide, ease
your foot off the accelerator
pedal and quickly steer the way you
want the vehicle to go. If you
start steering quickly enough, the
vehicle may straighten out. Always
be ready for a second skid if it
occurs.
4-12 Driving Your Vehicle

Of course, traction is reduced when
water, snow, ice, gravel, or other
material is on the road. For safety,
slow down and adjust your
driving to these conditions. It is
important to slow down on slippery
surfaces because stopping
distance will be longer and vehicle
control more limited.
While driving on a surface with
reduced traction, try your best to
avoid sudden steering, acceleration,
or braking, including reducing
vehicle speed by shifting to a lower
gear. Any sudden changes could
cause the tires to slide. You may not
realize the surface is slippery until
the vehicle is skidding. Learn to
recognize warning clues — such as
enough water, ice, or packed
snow on the road to make a
mirrored surface — and slow down
when you have any doubt.
Remember: Any Antilock Brake
System (ABS) helps avoid only the
braking skid.Off-Road Driving
The airbag system is designed to
work properly under a wide range
of conditions, including off-road
usage. Always wear your safety belt
and observe safe driving speeds,
especially on rough terrain.
Drinking and driving can be very
dangerous on any road and this is
certainly true for off-road driving.
At the very time you need special
alertness and driving skills, your
reexes, perceptions, and judgment
can be affected by even a small
amount of alcohol. You could
have a serious — or even
fatal — accident if you drink and
drive or ride with a driver who has
been drinking.Off-roading can be great fun
but has some denite hazards. The
greatest of these is the terrain
itself. When off-road driving, traffic
lanes are not marked, curves are not
banked, and there are no road
signs. Surfaces can be slippery,
rough, uphill, or downhill.
Avoid sharp turns and abrupt
maneuvers. Failure to operate the
vehicle correctly off-road could result
in loss of vehicle control or vehicle
rollover.
Off-roading involves some new
skills. That is why it is very important
that you read these driving tips
and suggestions to help make
off-road driving safer and more
enjoyable.
Driving Your Vehicle 4-13

The vehicle should be able to
traverse a 40% (22 degrees) side
slope at 6 mph (9.7 km/h) while fully
loaded on high friction surfaces.The vehicle can climb a
16 inch (40.6 cm) vertical step.
Step climbing is best done by
approaching the step at an angle
rather than straight on.
Brake and Accelerator
Operation Techniques for
Off-Road Driving
For logs, walls, rocks, severe
ditches, hills, sand, etc.
1. Bring the vehicle to a complete
stop. Do not rev the engine.
2. Select the proper transmission
and transfer case gear
range; usually 1 (First) gear,
Four-Wheel-Low Lock for such
obstacles.3. If wheel spin is experienced,
maintain steady throttle, with
your foot off the brake pedal, to
allow the Traction Control
System (TCS) to control the
wheel spin. TCS might not
operate if the brakes are applied.
4. If wheel spin cannot be controlled
by the TCS system, fully press
the brake pedal with your left foot
so all wheel spin is stopped.
5. Back away from the obstacle
so that a new approach can
be tried.
6. As the rst wheel crosses the
obstacle, be prepared to
alternate the brake and
accelerator pedal to maintain
control and avoid tire drop-off
from obstacles. Repeat this
process for the other wheels.
Driving Your Vehicle 4-17

For mounds, washouts, loose
up-hill slopes, ditches, etc.
When wheel spin occurs as the
vehicle is moving, the driver may
notice a slight shaking or shuddering
of the vehicle. This should be
stopped as soon as possible to
prevent damage to vehicle
components. This is the indication
that a loss of traction is occurring on
this terrain. The operator should:
1. Reduce speed and apply
the brakes.
2. Assess the terrain properly and
adjust vehicle speed and gear
ranges accordingly: Four-Wheel
High position for higher speeds
and Four-Wheel-Low Lock
for more torque and lower
speeds. Transmission 1 (First)
gear is generally recommended.3. Apply slight pressure to the
brake when the shaking or
shuddering sensation is felt,
keeping the vehicle moving in a
controlled manner.
4. Be prepared to alternate between
braking and accelerating through
the adverse terrain.
Getting Familiar with Off-Road
Driving
It is a good idea to practice in an
area that is safe and close to home
before you go into the wilderness.
Off-roading requires some new
and different skills.
Tune your senses to different
kinds of signals. Your eyes need
to constantly sweep the terrain
for unexpected obstacles. Your ears
need to listen for unusual tire or
engine sounds. Use your arms,
hands, feet, and body to respond to
vibrations and vehicle bounce.Controlling the vehicle is the key to
successful off-road driving. One of
the best ways to control the
vehicle is to control the speed.
At higher speeds:
You approach things faster and
have less time to react.
There is less time to scan the
terrain for obstacles.
The vehicle has more bounce
when driving over obstacles.
More braking distance is needed,
especially on an unpaved surface.
{CAUTION
When you are driving off-road,
bouncing and quick changes in
direction can easily throw you
out of position. This could cause
you to lose control and crash.
So, whether you are driving
on or off the road, you and
your passengers should wear
safety belts.
4-18 Driving Your Vehicle

For very large dips, ditches or
small washes, coast in, using the
engine as a brake (transmission
and transfer case lowest gears).
Then, use the low ranges in
the transmission and transfer case
to power out.
Roll The Tires Over Large Rocks
Do not straddle large rocks; drive
over them, letting the tire cover
the rock. The tread of the tire
is thicker and tougher than the
sidewall of the tire and is more
resilient to impact than underbody
components.Log Crossing
Using the proper technique, the
vehicle will cross logs up to
10 inches (25.4 cm) in diameter.
Approach the log at approximately a
15° angle (A) with the transmission
in 1 (First) and the transfer case
in Four-Wheel-Low Lock and “walk”
the vehicle over, one tire at a
time. It may be necessary to
modulate the brake pedal and
accelerator to avoid spin-out. Ease
the vehicle down from the log
with the brake.Driving on Hills
Off-road driving often takes you up,
down, or across a hill. Driving
safely on hills requires good
judgment and an understanding of
what the vehicle can and cannot do.
There are some hills that simply
cannot be driven, no matter how well
built the vehicle.
{CAUTION
Many hills are simply too steep for
any vehicle. If you drive up them,
you will stall. If you drive down
them, you cannot control your
speed. If you drive across them,
you will roll over. You could be
seriously injured or killed. If you
have any doubt about the
steepness, do not drive the hill.
4-20 Driving Your Vehicle