2007 BUICK RANDEZVOUS brakes

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 310.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modications on page 354.
Braking
SeeBrake System Warning Light on page 219.
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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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. The brakes may not have
time to cool between hard stops. The 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 vehicle’s engine ever stops while you are
driving, brake normally but do not pump the
brakes. If you do, the pedal may get harder to
push down. If the 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.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modications on page 354.Anti-Lock Brake System (ABS)
Your vehicle may have the Anti-Lock Brake
System (ABS), an advanced electronic braking
system that will help prevent a braking skid.
If your vehicle has ABS, this warning light on the
instrument panel will come on briey when you start
your vehicle.
When you start your engine, or when you begin to
drive away, ABS system will check itself. You
may hear a momentary motor or clicking noise
while this test is going on, and you may even
notice that your brake pedal moves or pulses a
little. This is normal.
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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
wheel.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, your computer keeps receiving
updates on wheel speed and controls braking
pressure accordingly.
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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 a slight brake pedal pulsation
or notice some noise, but this is normal.
Braking in Emergencies
At some time, nearly every driver gets into a
situation that requires hard braking.If you have ABS, you can steer and brake at the
same time. However, if you do not have ABS, your
rst reaction — to hit the brake pedal hard and hold
it down — may be the wrong thing to do. Your
wheels can stop rolling. Once they do, the vehicle
cannot respond to your steering. Momentum will
carry it in whatever direction it was headed when
the wheels stopped rolling. That could be off the
road, into the very thing you were trying to avoid, or
into traffic.
If you do not have ABS, use a “squeeze” braking
technique. This will give you maximum braking
while maintaining steering control. You can do this
by pushing on the brake pedal with steadily
increasing pressure.
In an emergency, you will probably want to
squeeze the brakes hard without locking the
wheels. If you hear or feel the wheels sliding, ease
off the brake pedal. This will help you retain
steering control. If you do have ABS, it is different.
SeeAnti-Lock Brake System (ABS) on page 307.
In many emergencies, steering can help you
more than even the very best braking.
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Traction Control System (TCS)
Your vehicle may have a traction control system
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 front wheels are
spinning or beginning to lose traction. When this
happens, the system works the front brakes and
reduces engine power to limit wheel spin.
The TRACTION ACTIVE message will come on
when the traction control system is limiting
wheel spin. SeeTraction Active Message on
page 227. You may feel or hear the system
working, but this is normal.
If your vehicle is in cruise control when the
traction control system begins to limit wheel spin,
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 181.If this message comes on and stays on or comes
on while you are driving, there’s a problem
with your traction control system.
SeeService Traction System Warning Message
on page 226. When this warning message is
on, the TRAC OFF light will come on to remind
you that 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. You should turn the system off if your vehicle
ever gets stuck in sand, mud or snow and rocking
the vehicle is required. SeeIf Your Vehicle is Stuck
in Sand, Mud, Ice, or Snow on page 331.
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Suppose you are steering through a sharp curve.
Then you suddenly apply the brakes. Both
control systems — steering and braking — have
to do their work where the tires meet the road.
Unless you have four-wheel anti-lock brakes,
adding the hard braking can demand too much of
those places. You can lose control.
The same thing can happen if you are steering
through a sharp curve and you suddenly
accelerate. Those two control systems — steering
and acceleration — can overwhelm those places
where the tires meet the road and make you lose
control. SeeTraction Control System (TCS) on
page 310.
What should you do if this ever happens? Ease up
on the brake or 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 354.
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 cannot; 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 306. 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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When it looks like a chance to pass is coming
up, start to accelerate but stay in the right lane
and do not get too close. Time your move so
you will be increasing speed as the time comes
to move into the other lane. If the way is clear to
pass, you will have a running start that more
than makes up for the distance you would lose
by dropping back. And if something happens to
cause you to cancel your pass, you need only
slow down and drop back again and wait for
another opportunity.
If other vehicles are lined up to pass a slow
vehicle, wait your turn. But take care that
someone is not trying to pass you as you pull
out to pass the slow vehicle. Remember to
glance over your shoulder and check the
blind spot.
Check your vehicle’s 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 vehicle’s inside
mirror, activate the right lane change signal and
move back into the right lane. Remember thatyour vehicle’s passenger side 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.
Do not overtake a slowly moving vehicle too
rapidly. Even though the brake lamps are not
ashing, it may be slowing down or starting
to turn.
If you are 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 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.
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If you have the Anti-Lock Brake System (ABS),
remember: It helps avoid only the braking skid. If
you do not have ABS, then in a braking skid,
where the wheels are no longer rolling, release
enough pressure on the brakes to get the wheels
rolling again. This restores steering control.
Push the brake pedal down steadily when you
have to stop suddenly. As long as the wheels are
rolling, you will have steering control.
Driving at Night
Night driving is more dangerous than day driving.
One reason is that some drivers are likely to
be impaired — by alcohol or drugs, with night
vision problems, or by fatigue.
Here are some tips on night driving.
Drive defensively.
Do not drink and drive.
Adjust the inside rearview mirror to reduce the
glare from headlamps behind you.
Since you cannot see as well, you may need
to slow down and keep more space between
you and other vehicles.
Slow down, especially on higher speed roads.
Your vehicle’s headlamps can light up only so
much road ahead.
In remote areas, watch for animals.
If you are tired, pull off the road in a safe
place and rest.
No one can see as well at night as in the daytime.
But as we get older these differences increase.
A 50-year-old driver may require at least twice as
much light to see the same thing at night as a
20-year-old.
What you do in the daytime can also affect your
night vision. For example, if you spend the
day in bright sunshine you are wise to wear
sunglasses. Your eyes will have less trouble
adjusting to night. But if you are driving, do not
wear sunglasses at night. They may cut down on
glare from headlamps, but they also make a
lot of things invisible.
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