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 291.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modi cations on page 333.
Braking
SeeBrake System Warning Light on page 178.
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 hear the anti-lock pump or motor
operate, and feel the brake pedal pulsate, 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 that
limits wheel spin. This is especially useful in
slippery road conditions. The system operates
only if it senses that one or more of the wheels
are spinning or beginning to lose traction.
When this happens, the system works the brakes
and reduces engine power to limit wheel spin.
This light will come
on when your traction
control system is
limiting wheel spin.
You may feel or hear the system working, but this
is normal.
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.
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This light will come
on along with the
ALL WHEEL DRIVE
OFF message when
the rear drive system
is overheating.
This light will turn off when the rear drive system
cools down. If this light stays on, it must be
reset. To reset the light, turn the ignition off
and then back again. If the light stays on, see
your dealer for service.
See “All Wheel Drive Off” underDIC Warnings
and Messages on page 198for more information.Steering
Electric Power Steering
If the engine stalls while you are driving, the
power steering assist system will continue
to operate until you are able to stop your vehicle.
If you lose power steering assist because the
electric power steering system is not functioning,
you can steer, but it will take more effort.
If you turn the steering wheel in either direction
several times until it stops, or hold the steering
wheel in the stopped position for an extended
amount of time, you may notice a reduced amount
of power steering assist. The normal amount of
power steering assist should return shortly after
a few normal steering movements.
The electric power steering system does not
require regular maintenance. If you suspect
steering system problems, such as abnormally
high steering effort for a prolonged period of time,
contact your dealer for service repairs.
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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 291
Traction Control System (TCS) andStabiliTrak
®
System on page 292.
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
Modi cations on page 333.
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