brake GMC ENVOY 1999 Owner's Manual

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This light should come on
briefly when you turn the
ignition key to RUN. If it
doesn't come on then, have
it fixed so it will be ready to
warn you if there's
a problem.
If the light comes on while you are driving, pull off the
road and stop carefully. You may notice that the pedal is
harder to push. Or, the pedal may go closer to the floor.
It may take longer to stop. If the light is still on, have the
vehicle towed for service. (See ªTowing Your Vehicleº
in the Index.)
CAUTION:
Your brake system may not be working properly
if the brake system warning light is on. Driving
with the brake system warning light on can lead
to an accident. If the light is still on after you've
pulled off the road and stopped carefully, have
the vehicle towed for service.
Anti-Lock Brake System Warning Light
With the anti-lock brake
system, this light will come
on when you start your
engine and may stay on for
several seconds.
That's normal.
If the light stays on, or comes on when you're driving,
your vehicle needs service. If the regular brake system
warning light isn't on, you still have brakes, but you
don't have anti
-lock brakes. If the regular brake system
warning light is also on, you don't have anti
-lock brakes
and there's a problem with your regular brakes. See
ªBrake System Warning Lightº earlier in this section.
The anti
-lock brake system warning light should come
on briefly when you turn the ignition key to RUN. If the
light doesn't come on then, have it fixed so it will be
ready to warn you if there is a problem.
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Defensive Driving
The best advice anyone can give about driving is:
Drive defensively.
Please start with a very important safety device in your
vehicle: Buckle up. (See ªSafety Beltsº in the Index.)Defensive driving really means ªbe ready for anything.º
On city streets, rural roads or freeways, it means
ªalways expect the unexpected.º
Assume that pedestrians or other drivers are going to be
careless and make mistakes. Anticipate what they might
do. Be ready for their mistakes.
Rear
-end collisions are about the most preventable of
accidents. Yet they are common. Allow enough
following distance. It's the best defensive driving
maneuver, in both city and rural driving. You never
know when the vehicle in front of you is going to brake
or turn suddenly.
Defensive driving requires that a driver concentrate on
the driving task. Anything that distracts from the
driving task
-- such as concentrating on a cellular
telephone call, reading, or reaching for something on
the floor
-- makes proper defensive driving more
difficult and can even cause a collision, with resulting
injury. Ask a passenger to help do things like this, or
pull off the road in a safe place to do them yourself.
These simple defensive driving techniques could save
your life.
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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're driving on snow or ice, it's
easy to ask more of those control systems than the tires
and road can provide. That means you can lose control
of your vehicle.
Braking
Braking action involves perception time and
reaction time.
First, you have to decide to push on the brake pedal.
That's perception time. Then you have to bring up your
foot and do it. That's reaction time.
Average reaction time is about 3/4 of a second. But
that's 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 3/4 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's pavement or
gravel); the condition of the road (wet, dry, icy); tire
tread; the condition of your brakes; the weight of the
vehicle and the amount of brake force applied.
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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. Your brakes may not have time to cool between
hard stops. Your brakes will wear out much faster if you
do a lot of heavy braking. If you keep pace with the
traffic and allow realistic following distances, you will
eliminate a lot of unnecessary braking. That means
better braking and longer brake life.
If your engine ever stops while you're driving, brake
normally but don't pump your brakes. If you do, the
pedal may get harder to push down. If your engine
stops, you will still have some power brake assist. But
you will use it when you brake. Once the power assist is
used up, it may take longer to stop and the brake pedal
will be harder to push.
Anti-Lock Brakes (ABS)
Your vehicle has anti-lock brakes (ABS). ABS is an
advanced electronic braking system that will help
prevent a braking skid.
When you start your engine and begin to drive away,
your anti
-lock brake system will check itself. You may
hear a momentary motor or clicking noise while this test
is going on. This is normal.
If there's a problem with the
anti
-lock brake system, this
warning light will stay on.
See ªAnti
-Lock Brake
System Warning Lightº in
the Index.
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Here's how anti-lock works. Let's say the road is wet.
You're driving safely. Suddenly an animal jumps out in
front of you.
You slam on the brakes. Here's 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.
You can 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 doesn't 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 won't 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
Don't pump the brakes. Just hold the brake pedal down
firmly and let anti
-lock work for you. You may feel the
brakes vibrate, or you may notice some noise, but this is
normal. Your anti
-lock brakes work at all
times
-- whether you are in two-wheel drive or
four
-wheel drive.
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.
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's important to take curves at a reasonable speed.
A lot of the ªdriver lost controlº accidents mentioned on
the news happen on curves. Here's 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's no traction, inertia will keep
the vehicle going in the same direction. If you've ever
tried to steer a vehicle on wet ice, you'll understand this.
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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're in a curve, speed is the one factor you
can control.
Suppose you're 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.
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'll 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 ªdriveº 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
find 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't; there isn't room. That's
the time for evasive action
-- steering around
the problem.
Your vehicle can perform very well in emergencies like
these. First apply your brakes. (See ªBraking in
Emergenciesº earlier in this section.) 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.
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Check your mirrors, glance over your shoulder and
start your left lane change signal before moving out
of the right lane to pass. When you are far enough
ahead of the passed vehicle to see its front in your
inside mirror, activate your right lane change signal
and move back into the right lane. (Remember that
your right outside mirror is convex. The vehicle you
just passed may seem to be farther away from you
than it really is.)

Try not to pass more than one vehicle at a time
on two
-lane roads. Reconsider before passing the
next vehicle.

Don't overtake a slowly moving vehicle too rapidly.
Even though the brake lamps are not flashing, it may
be slowing down or starting to turn.

If you're being passed, make it easy for the
following driver to get ahead of you. Perhaps you
can ease a little to the right.
Loss of Control
Let's review what driving experts say about what
happens when the three control systems (brakes, steering
and acceleration) don't have enough friction where the
tires meet the road to do what the driver has asked.
In any emergency, don't 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
ªoverdrivingº 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
aren't 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 and an acceleration skid are best
handled by easing your foot off the accelerator pedal.
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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'll
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 ªmirrored surfaceº
-- and slow down
when you have any doubt.
Remember: Any anti
-lock brake system (ABS) helps
avoid only the braking skid.
Driving Guidelines
This multipurpose passenger vehicle is defined as a
utility vehicle in Consumer Information Regulations
issued by the National Highway Traffic Safety
Administration (NHTSA) of the United States
Department of Transportation. Utility vehicles have
higher ground clearance and a narrower track to make
them capable of performing in a wide variety of off
-road
applications. Specific design characteristics give them a
higher center of gravity than ordinary cars. An
advantage of the higher ground clearance is a better
view of the road allowing you to anticipate problems.
They are not designed for cornering at the same speeds
as conventional two
-wheel-drive vehicles any more than
low
-slung sports cars are designed to perform
satisfactorily under off
-road conditions. If at all
possible, avoid sharp turns or abrupt maneuvers. As with
other vehicles of this type, failure to operate this vehicle
correctly may result in loss of control or
vehicle rollover.
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Off-Road Driving with Your
Four
-Wheel-Drive Vehicle
Also, see ªAnti-Lock Brakesº in the Index.
Off
-road driving can be great fun. But it does have some
definite hazards. The greatest of these is the
terrain itself.
ªOff
-roadingº means you've left the great North
American road system behind. Traffic lanes aren't
marked. Curves aren't banked. There are no road signs.
Surfaces can be slippery, rough, uphill or downhill. In
short, you've gone right back to nature.
Off
-road driving involves some new skills. And that's
why it's very important that you read this guide. You'll
find 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 inflated? Are the fluid levels
up where they should be? What are the local laws that
apply to off
-roading where you'll be driving? If you
don't 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.
Loading Your Vehicle for Off-Road Driving
There are some important things to remember about
how to load your vehicle.

The heaviest things should be on the load floor and
forward of your rear axle. Put heavier items as far
forward as you can.

Be sure the load is secured properly, so driving on
the off
-road terrain doesn't toss things around.
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