2007 HUMMER H3 traction control

Control of a Vehicle
You have three systems that make your
vehicle go where you want it to go. They are
the brakes, the steering, and the accelerator.
All three systems have to do their work at
the places where the tires meet the road.
Sometimes, as when you are driving on snow
or ice, it is easy to ask more of those control
systems than the tires and road can provide.
That means you can lose control of your vehicle.
SeeTraction Control System (TCS) on page 241.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modications on page 314.
Braking
SeeBrake System Warning Light on page 182.
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.
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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 your 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 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 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 159.
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If your vehicle has a Driver information Center
(DIC), a TRACTION FAILED 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 196for more information.
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-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modications on page 314for more information.
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StabiliTrak®System
Your vehicle has a vehicle stability enhancement
system called StabiliTrak®. It is an advanced
computer controlled system that assists you with
directional control of the vehicle in difficult
driving conditions.
StabiliTrak
®activates when the computer senses
a discrepancy between your 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 you rst start your vehicle and begin to drive
away, the system performs several diagnostic
checks to insure there are no problems. You may
hear or feel the system working. This is normal and
does not mean there is a problem with your vehicle.
If there is a problem detected with StabiliTrak
®,
a SERVICE STAB SYS message will be displayed
on the Driver Information Center (DIC). See
DIC Warnings and Messages on page 196for
more information. When this message is displayed,
the system is not operational. Adjust your driving
accordingly.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. See
Full-Time Four-Wheel Drive on page 111for 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 241.
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. See “Cruise Control on
page 159for more information.
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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
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 241
andStabiliTrak
®System on page 244.
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.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modications on page 314.
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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.
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 241
andStabiliTrak
®System on page 244.
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.
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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 will not operate
if the brakes are applied, even slightly.
4. If wheel spin cannot be controlled by the
system, fully press the brake pedal with
your left foot so all wheel spin is halted.
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.
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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.
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