2004 GMC ENVOY XL wheel

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 wheels are slowing down. If one
of the wheels is about to stop rolling, the computer will
separately work the brakes at each front wheel and at
both rear wheels.The anti-lock system 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, your computer keeps receiving updates
on wheel speed and controls braking pressure
accordingly.
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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 Assist System (TAS)
Your two-wheel drive vehicle may have a Traction Assist
System (TAS) that limits wheel spin. This is especially
useful in slippery road conditions. The system operates
only if it senses that one or both of the rear wheels are
spinning or beginning to lose traction. When this
happens, the system reduces engine power to limit
wheel spin.
The low traction symbol next to the button will come on
when the TAS is limiting wheel spin. You may feel or
hear the system working, but this is normal.
The Traction Assist System may operate on dry roads
under some conditions. When this happens, you
may notice a reduction in acceleration. This is normal
and doesn’t mean there’s a problem with your
vehicle. Examples of these conditions include a 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 TAS 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 3-7. When the traction control off symbol
on the button is on, the TAS is off and will not limit
wheel spin. Adjust your driving accordingly.
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The traction control off symbol on the button will come
on under the following conditions:
The Traction Assist System is turned off, either by
pressing the TAS on/off button or by turning off
the automatic engagement feature of the TAS.
The transmission is in FIRST (1) gear; TAS will not
operate in this gear. This is normal.
The vehicle is driven on an extremely rough road.
When the vehicle leaves the rough surface, slows
down or stops, the light will go off and TAS will
be on again. This is normal.
A Traction Assist System, Anti-Lock Brake System
or engine-related problem has been detected and
the vehicle needs service.
The Traction Assist System, as delivered from the
factory, will automatically come 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 TAS off if you ever need to. You
should turn the TAS off if your vehicle ever gets stuck in
sand, mud or snow and rocking the vehicle is required.
To turn the system on or off, press the TAS button
located near the shift lever. If you used the button to turn
the system off, the traction control off symbol on the
button will come on and stay on.You can turn the system back on at any time by pressing
the button again. The traction control off symbol on the
button should go off.
If desired, you can change the TAS automatic
engagement feature so that the system will not come
on automatically when the engine is started. To do so:
1. Turn the ignition to RUN.
2. Move the shift lever to NEUTRAL.
3. Apply the brake pedal and press the accelerator
pedal to the oor.
4. Press and hold the TAS button for at least six
seconds.
5. Release the TAS button and both pedals.
6. Start the engine and wait a few seconds.
The next time you start your vehicle, the TAS will not
automatically come on. You can restore the automatic
feature by using the same procedure. Whether the TAS
is set to come on automatically or not, you can always
turn the system on or off by pressing the TAS button.
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Locking Rear Axle
If your vehicle has this feature, your locking rear axle
can give you additional traction on snow, mud, ice,
sand or gravel. It works like a standard axle most of the
time, but when one of the rear wheels has no traction
and the other does, this feature will allow the wheel with
traction to move the vehicle.
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 whenyou 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 Assist
System (TAS) 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.
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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.
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. You
can avoid these problems by braking — if you can stop
in time. But sometimes you can not; there is not
room. That is the time for evasive action — steering
around the problem.
Your vehicle can perform very well in emergencies like
these. First apply your brakes.
SeeBraking on page 4-6. It is better to remove as much
speed as you can from a possible 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 you are holding the steering wheel at
the recommended 9 and 3 o’clock positions, you
can turn it 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.
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Off-Road Recovery
You may nd that your right wheels have dropped off the
edge of a road onto the shoulder while you are 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 your vehicle straddles the edge of
the pavement. You can turn the steering wheel up to
one-quarter turn until the right front tire contacts
the pavement edge. Then turn your steering wheel
to go straight down the roadway.
Passing
The driver of a vehicle about to pass another on a
two-lane highway waits for just the right moment,
accelerates, moves around the vehicle ahead, then
goes back into the right lane again. A simple maneuver?
Not necessarily! Passing another vehicle on a two-lane
highway is a potentially dangerous move, since the
passing vehicle occupies the same lane as oncoming
traffic for several seconds. A miscalculation, an error in
judgment, or a brief surrender to frustration or anger
can suddenly put the passing driver face to face with the
worst of all traffic accidents — the head-on collision.
So here are some tips for passing:
“Drive ahead.” Look down the road, to the sides
and to crossroads for situations that might affect
your passing patterns. If you have any doubt
whatsoever about making a successful pass,
wait for a better time.
Watch for traffic signs, pavement markings and
lines. If you can see a sign up ahead that might
indicate a turn or an intersection, delay your pass.
A broken center line usually indicates it is all
right to pass (providing the road ahead is clear).
Never cross a solid line on your side of the lane or
a double solid line, even if the road seems empty
of approaching traffic.
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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 you have the Traction Assist System, remember: It
helps avoid only the acceleration skid. If you do not have
this system, or if the system is off, then an acceleration
skid is also 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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Off-Road Driving with Your
Four-Wheel-Drive Vehicle
This off-road guide is for vehicles that have four-wheel
drive. Also, seeBraking on page 4-6. If your vehicle
does not have four-wheel drive, you should not
drive off-road unless you are on a level, solid surface.
Off-road driving can be great fun. But it does have
some denite hazards. The greatest of these is
the terrain itself.
“Off-roading” means you have left the great North
American road system behind. Traffic lanes are not
marked. Curves are not banked. There are no
road signs. Surfaces can be slippery, rough, uphill or
downhill. In short, you have gone right back to nature.
Off-road driving involves some new skills. And that
is why it is very important that you read this guide.
You will nd many driving tips and suggestions.
These will help make your off-road driving safer
and more enjoyable.
Before You Go Off-Roading
There are some things to do before you go out. For
example, be sure to have all necessary maintenance and
service work done. Check to make sure all underbody
shields (if so equipped) are properly attached.
Be sure you read all the information about your
four-wheel-drive vehicle in this manual.
Is there enough fuel? Is the spare tire fully inated?
Are the uid levels up where they should be? What
are the local laws that apply to off-roading where
you will be driving? If you do not know, you should
check with law enforcement people in the area.
Will you be on someone’s private land? If so, be
sure to get the necessary permission.
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