2004 HUMMER H2 traction control

Remember: Anti-lock 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
your brakes if that vehicle suddenly slows or stops.
Always leave enough room up ahead to stop, even
though you have anti-lock brakes.
Using Anti-Lock
Do not pump the brakes. Just hold the brake pedal
down rmly and let anti-lock work for you. You may feel
the brakes vibrate, or you may notice some noise,
but this is normal.
Braking in Emergencies
With anti-lock, 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.
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. See
“Cruise Control” underTurn Signal/Multifunction
Lever on page 3-6.
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Another feature of this system is the Traction Control 2
(TC2) mode. TC2 should be selected for improved
traction and system performance when the vehicle is on
loose surfaces such as deep sand or mud.
To enter this mode,
press the TC2 button
located on the instrument
panel to the right of
the steering wheel.
TC2 only operates in the following transfer case modes:
4HI Lock
4LO Lock
4LO Lock and Rear Axle Lock
SeeLocking Rear Axle on page 4-11for more
information on the rear axle lock.It will not operate in 4HI. If the TC2 button is pressed
while in 4HI, the light will ash for about 15 seconds and
then go out. The light should also come on briey
when you turn the ignition key to RUN; if it doesn’t see
your dealer for service.
If you restart your engine, the system reverts to the
standard TCS mode.
The traction off light will
come on when a Traction
Control System or
Anti-Lock Brake System
problem has been detected
and the vehicle needs
service. SeeTraction Off
Light on page 3-35.
When the traction off light is on, adjust your driving
accordingly.
The traction control system, as delivered from the
factory, will automatically come on whenever you start
your vehicle.
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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
Driving on Curves
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 your 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 4-9.
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.
Speed limit signs near curves warn that you should
adjust your speed. Of course, the posted speeds
are based on good weather and road conditions. Under
less favorable conditions you will want to go slower.
If you need to reduce your speed as you approach
a curve, do it before you enter the curve, while your front
wheels are straight ahead.
Try to adjust your speed so you can “drive” through the
curve. Maintain a reasonable, steady speed. Wait to
accelerate until you are out of the curve, and then
accelerate gently into the straightaway.
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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 your vehicle’s
three control systems. In the braking skid, your 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.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 engine braking 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 anti-lock brake system (ABS) helps
avoid only the braking skid.
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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 occuring on this
terrain. The operator should:
1. Reduce throttle, brake wheels.
2. Assess the terrain properly and adjust vehicle
speed and gear ranges accordingly: 4HI position
for higher speeds and 4LO 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 modulate the brake and throttle
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 listenfor 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.
{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’re
driving on or off the road, you and your
passengers should wear safety belts.
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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,
your wheels can leave the ground. If this happens,
even with one or two wheels, you can not control the
vehicle as well or at all.
Because you will be on an unpaved surface, it is
especially important to avoid sudden acceleration,
sudden turns or sudden braking.
In a way, off-road driving requires a different kind of
alertness from driving on paved roads and highways.
There are no road signs, posted speed limits or
signal lights. You have to use your own good judgment
about what is safe and what is not.
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. SeeDrunken Driving on page 4-3.
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Log Crossing.Using the proper technique, the
HUMMER H2 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 FIRST (1) and the transfer
case in 4LO LOCK and “walk” the HUMMER H2 over,
one tire at a time. As with all obstacles, face your tires
perpendicular to the object for best traction and tire life. It
may be necessary to modulate your brake pedal and
accelerator to avoid spin-out. Ease the vehicle down from
the log with your brake.Driving on Off-Road 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 your vehicle can and can
not do. There are some hills that simply can not 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 can not 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.
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Approaching a Hill
When you approach a hill, you need to decide if it is
one of those hills that is just too steep to climb, descend
or cross. Steepness can be hard to judge. On a very
small hill, for example, there may be a smooth, constant
incline with only a small change in elevation where
you can easily see all the way to the top. On a large hill,
the incline may get steeper as you near the top, but
you may not see this because the crest of the hill
is hidden by bushes, grass or shrubs.
Here are some other things to consider as you approach
a hill.
Is there a constant incline, or does the hill get
sharply steeper in places?
Is there good traction on the hillside, or will the
surface cause tire slipping?
Is there a straight path up or down the hill so you
will not have to make turning maneuvers?
Are there obstructions on the hill that can block
your path (boulders, trees, logs or ruts)?
What is beyond the hill? Is there a cliff, an
embankment, a drop-off, a fence? Get out and walk
the hill if you do not know. It is the smart way to
nd out.
Is the hill simply too rough? Steep hills often have
ruts, gullies, troughs and exposed rocks because
they are more susceptible to the effects of erosion.
Driving Uphill
Once you decide you can safely drive up the hill, you
need to take some special steps.
Use transmission and transfer case low gear and
get a rm grip on the steering wheel.
Get a smooth start up the hill and try to maintain
your speed. Do not use more power than you
need, because you do not want your wheels to start
spinning or sliding.
Let the traction system work to control any wheel
slippage. TC2 is designed to allow moderate
wheel spin with some capability to dig in and power
up the hill.
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