2008 HUMMER H3 traction control

For persons under 21, it is against the law in every
U.S. state to drink alcohol. There are good medical,
psychological, and developmental reasons for
these laws.
The obvious way to eliminate the leading highway
safety problem is for people never to drink alcohol
and then drive.
Medical research shows that alcohol in a person’s
system can make crash injuries worse, especially
injuries to the brain, spinal cord, or heart. This means
that when anyone who has been drinking — driver
or passenger — is in a crash, that person’s chance
of being killed or permanently disabled is higher than
if the person had not been drinking.
Control of a Vehicle
The following three systems help to control your vehicle
while driving — brakes, steering, and accelerator.
At times, as when driving on snow or ice, it is easy to
ask more of those control systems than the tires and
road can provide. Meaning, you can lose control of your
vehicle. SeeTraction Control System (TCS) on page 4-5.
Adding non-dealer/non-retailer accessories can affect
your vehicle’s performance. SeeAccessories and
Modifications on page 5-3.
Braking
SeeBrake System Warning Light on page 3-33.
Braking action involves perception time and reaction
time. First, you have to decide to push on the brake
pedal. That is perception time. Then you have to bring
up your foot and do it. That is reaction time.
Average reaction time is about three-fourths of a
second. But that is only an average. It might be less
with one driver and as long as two or three seconds or
more with another. Age, physical condition, alertness,
coordination, and eyesight all play a part. So do alcohol,
drugs, and frustration. But even in three-fourths of a
second, a vehicle moving at 60 mph (100 km/h) travels
66 feet (20 m). That could be a lot of distance in an
emergency, so keeping enough space between
your vehicle and others is important.
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.
4-3

ABS can change the brake pressure faster than any
driver could. The computer is programmed to make the
most of available tire and road conditions. This can
help you steer around the obstacle while braking hard.
As you brake, the computer keeps receiving updates
on wheel speed and controls braking pressure
accordingly.
Remember: ABS does not change the time you need to
get your foot up to the brake pedal or always decrease
stopping distance. If you get too close to the vehicle
in front of you, you will not have time to apply the brakes
if that vehicle suddenly slows or stops. Always leave
enough room up ahead to stop, even though you
have ABS.
Using ABS
Do not pump the brakes. Just hold the brake pedal down
rmly and let antilock work for you. You might feel the
brakes vibrate or notice some noise, but this is normal.
Braking in Emergencies
With ABS, you can steer and brake at the same time.
In many emergencies, steering can help you more
than even the very best braking.
Traction Control System (TCS)
Your 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, the system applies the brakes to limit
wheel spin and also reduces engine power. You may feel
or hear the system working, but this is normal.
The Traction Control System may operate on dry roads
under some conditions. When this happens, you may
notice a reduction in acceleration or a pumping sound.
This is normal and doesn’t mean there’s a problem with
your 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 your vehicle is in cruise control when the TCS begins
to limit wheel spin, the cruise control will automatically
disengage. When road conditions allow you to safely
use it again, you may re-engage the cruise control.
SeeCruise Control on page 3-11.
If your vehicle has a Driver information Center (DIC),
a TRACTION FAULT message will appear when a
Traction Control System or Anti-Lock Brake System
problem has been detected and the vehicle needs
service. SeeDIC Warnings and Messages on page 3-43
for more information.
4-5

When this message is on, the system will not limit
wheel spin. Adjust your driving accordingly.
The traction control system automatically comes on
whenever you start your vehicle. To limit wheel
spin, especially in slippery road conditions, you should
always leave the system on. But you can turn the
traction control system off if you ever need to.
To turn the system off,
press and hold the TCS
button for ve seconds.
This light will come
on steady when the
traction control system
has been turned off.
This light ashes when
TCS is active.If you press and hold the TC button for ve seconds,
the traction control system will turn off and a TRAC OFF
message will appear on the DIC. Press the TC button
again to turn the system back on. The TRAC OFF
message will then go off. The traction control system
will reset itself at each ignition cycle.
Adding non-dealer/non-retailer accessories can affect
your vehicle’s performance. SeeAccessories and
Modifications on page 5-3for more information.
Locking Rear Axle
Your vehicle may have this feature. The locking rear axle
can give your vehicle additional traction from the rear
wheels when traveling in off-road situations such as mud,
snow, sand, steep hills and uneven terrain.
The button used to turn
this feature on or off is
located to the right of
the transfer case buttons
on the center of the
instrument panel.
4-6

StabiliTrak®comes on automatically whenever you
start your vehicle. However, when the transfer case is
placed in Four-Wheel-Low Lock mode, StabiliTrak
®
is automatically disabled. SeeFull-Time Four-Wheel
Drive on page 2-27for more information. To help assist
you with directional control of the vehicle, you should
always leave the system on. You can turn StabiliTrak
®
off if you ever need to using the TC (traction control)
on/off button. If you press and hold the TC button for
ve seconds, the StabiliTrak
®system and the traction
control system will turn off. When this is done, the
STAB SYS OFF message will be displayed on the DIC.
Press the TC button again to turn StabiliTrak
®back
on. SeeTraction Control System (TCS) on page 4-5.
If your vehicle is in cruise control when the StabiliTrak
®
activates, the cruise control will automatically
disengage. When road conditions allow you to safely
use it again, you may reengage the cruise control.
SeeCruise Control on page 3-11for more information.
Steering
Power Steering
If you lose power steering assist because the engine
stops or the system is not functioning, you can steer
but it will take much more effort.
Steering Tips
It is important to take curves at a reasonable speed.
A lot of the “driver lost control” accidents mentioned
on the news happen on curves. Here is why:
Experienced driver or beginner, each of us is subject
to the same laws of physics when driving on curves.
The traction of the tires against the road surface makes
it possible for the vehicle to change its path when you
turn the front wheels. If there is no traction, inertia will
keep the vehicle going in the same direction. If you
have ever tried to steer a vehicle on wet ice, you will
understand this.
The traction you can get in a curve depends on the
condition of the tires and the road surface, the angle at
which the curve is banked, and your speed. While you
are in a curve, speed is the one factor you can control.
Suppose you are steering through a sharp curve.
Then you suddenly accelerate. Both control
systems — steering and acceleration — have to do their
work where the tires meet the road. Adding the sudden
acceleration can demand too much of those places.
You can lose control. SeeTraction Control System (TCS)
on page 4-5andStabiliTrak
®System on page 4-7.
What should you do if this ever happens? Ease up on
the accelerator pedal, steer the vehicle the way you
want it to go, and slow down.
4-8

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 your 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.
A cornering skid is best handled by easing your foot
off the accelerator pedal.
Remember: Any traction control system helps avoid
only the acceleration skid. If your traction system is
off, then an acceleration skid is also best handled
by easing your foot off the accelerator pedal.
SeeTraction Control System (TCS) on page 4-5
andStabiliTrak
®System on page 4-7.If your 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,
your vehicle may straighten out. Always be ready
for a second skid if it occurs.
Of course, traction is reduced when water, snow, ice,
gravel, or other material is on the road. For safety,
you will want to 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 your 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.
4-11

Your 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 FIRST (1) 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.
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 FIRST (1) 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-road driving does require some new and different
skills. Here is what we mean.
Tune your senses to different kinds of signals. Your
eyes, for example, need to constantly sweep the terrain
for unexpected obstacles. Your ears need to listen
for unusual tire or engine sounds. With your arms,
hands, feet, and body, you will need to respond to
vibrations and vehicle bounce.
Controlling your vehicle is the key to successful off-road
driving. One of the best ways to control your vehicle
is to control your speed. Here are some things to keep
in mind. At higher speeds:
You approach things faster and you have less time
to scan the terrain for obstacles.
You have less time to react.
You have more vehicle bounce when you drive
over obstacles.
You will need more distance for braking, especially
since you are on an unpaved surface.
4-18

{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.
Scanning the Terrain
Off-road driving can take you over many different kinds
of terrain. You need to be familiar with the terrain
and its many different features. Here are some things
to consider.
Surface Conditions:Off-roading can take you over
hard-packed dirt, gravel, rocks, grass, sand, mud, snow,
or ice. Each of these surfaces affects the steering,
acceleration, and braking of your vehicle in different
ways. Depending upon the kind of surface you are on,
you may experience slipping, sliding, wheel spinning,
delayed acceleration, poor traction, and longer
braking distances.Surface Obstacles:Unseen or hidden obstacles
can be hazardous. A rock, log, hole, rut, or bump can
startle you if you are not prepared for them. Often
these obstacles are hidden by grass, bushes, snow,
or even the rise and fall of the terrain itself.
Here are some things to consider:
Is the path ahead clear?
Will the surface texture change abruptly up ahead?
Does the travel take you uphill or downhill?
There is more discussion of these subjects later.
Will you have to stop suddenly or change
direction quickly?
When you drive over obstacles or rough terrain, keep
a rm grip on the steering wheel. Ruts, troughs, or other
surface features can jerk the wheel out of your hands
if you are not prepared.
When possible, it is a good practice to survey the
landscape ahead on foot prior to driving to observe
hidden obstacles.
When you drive over bumps, rocks, or other obstacles,
the wheels can leave the ground. If this happens,
even with one or two wheels, you cannot control the
vehicle as well or at all.
4-19