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 4-9.
Adding non-GM accessories can affect your vehicle’s
performance. SeeAccessories and Modi cations
on page 5-3.
Braking
SeeBrake System Warning Light on page 3-30.
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.
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 Modi cations
on page 5-3.
4-6
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
cluster will come on brie y
when you start your
vehicle.
When you start your engine, or when you begin to drive
away, ABS 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.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.
4-7
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.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.
4-8
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 4-7.
In many emergencies, steering can help you more than
even the very best braking.
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 reduces
engine power and may also upshift the transaxle and
apply the front brakes to limit wheel spin.
This light will ash when
your traction control system
is limiting wheel spin.
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
re-engage the cruise control. SeeCruise Control
on page 3-10.
4-9
Driving in Rain and on Wet Roads
Rain and wet roads can mean driving trouble. On a wet
road, you cannot stop, accelerate, or turn as well
because your tire-to-road traction is not as good as on
dry roads. And, if your tires do not have much tread
left, you will get even less traction. It is always wise to
go slower and be cautious if rain starts to fall while
you are driving. The surface may get wet suddenly when
your re exes are tuned for driving on dry pavement.The heavier the rain, the harder it is to see. Even if your
windshield wiper blades are in good shape, a heavy
rain can make it harder to see road signs and
traffic signals, pavement markings, the edge of the road,
and even people walking.
It is wise to keep your windshield wiping equipment in
good shape and keep your windshield washer uid
reservoir lled with washer uid. Replace your
windshield wiper inserts when they show signs of
streaking or missing areas on the windshield, or when
strips of rubber start to separate from the inserts.
{CAUTION:
Wet brakes can cause accidents. They may not
work as well in a quick stop and may cause
pulling to one side. You could lose control of
the vehicle.
After driving through a large puddle of water
or a car wash, apply your brake pedal lightly
until your brakes work normally.
Driving too fast through large water puddles or even
going through some car washes can cause problems,
too. The water may affect your brakes. Try to avoid
puddles. But if you cannot, try to slow down before
you hit them.
4-17