2009 CHEVROLET IMPALA brakes

Antilock Brake System (ABS)
The vehicle might have the Antilock Brake System
(ABS), an advanced electronic braking system that helps
prevent a braking skid.
If the vehicle has ABS,
this warning light on the
instrument panel cluster
comes on briey when the
vehicle is started.
When the engine is started, or when the vehicle begins
to drive away, ABS checks itself. A momentary motor
or clicking noise might be heard while this test is going
on, and it might even be noticed that the 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 the 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.ABS can change the brake pressure to each wheel, as
required, faster than any driver could. This can help
the driver steer around the obstacle while braking hard.
As the brakes are applied, the computer keeps
receiving updates on wheel speed and controls braking
pressure accordingly.
Remember: ABS does not change the time needed to get
a foot up to the brake pedal or always decrease stopping
distance. If you get too close to the vehicle in front of you,
there will not be enough time to apply the brakes if that
vehicle suddenly slows or stops. Always leave enough
room up ahead to stop, even with ABS.
Using ABS
Do not pump the brakes. Just hold the brake pedal
down rmly and let antilock work. A slight brake pedal
pulsation might be felt or some noise might be
heard, but this is normal.
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Braking in Emergencies
At some time, nearly every driver gets into a situation
that requires hard braking.
If the vehicle has ABS, it allows the driver to steer and
brake at the same time. However, if the vehicle does
not have ABS, the rst reaction — to hit the brake pedal
hard and hold it down — might be the wrong thing to
do. The wheels can stop rolling. Once they do, the
vehicle cannot respond to the driver’s 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 the driver was trying
to avoid, or into traffic.
If the vehicle does not have ABS, use a “squeeze”
braking technique. This gives maximum braking while
maintaining steering control. 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 helps retain steering control. With ABS, it is
different. SeeAntilock Brake System (ABS) on page 4-5.
In many emergencies, steering can help more than
even the very best braking.
Electronic Stability Control (ESC)
Your vehicle may have an Electronic Stability Control
(ESC) system which combines antilock brake, traction
and stability control systems and helps the driver
maintain directional control of the vehicle in most driving
conditions.
When you rst start your vehicle and begin to drive
away, the system performs several diagnostic checks to
ensure there are no problems. You may hear or feel
the system working. This is normal and does not mean
there is a problem with your vehicle. The system
should initialize before the vehicle reaches 20 mph
(32 km/h).
If the system fails to turn on or activate, the ESC/TCS
light will be on solid, and the SERVICE STABILITRAK
message will be displayed.
For more information, seeDriver Information Center
(DIC) on page 3-42.
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If the problem does not clear after restarting the vehicle,
you should see your dealer/retailer for service. See
DIC Warnings and Messages on page 3-49for more
information.
Adding non-dealer/non-retailer accessories can affect
your vehicle’s performance. SeeAccessories and
Modifications on page 5-3for more information.
Traction Control System (TCS)
The vehicle may have a Traction Control System (TCS)
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 transmission and apply the front brakes to limit
wheel spin.
This light will ash
when the TCS is limiting
wheel spin.
The system may be heard or felt while it is working, but
this is normal.If cruise control is being used when TCS begins to limit
wheel spin, the cruise control will automatically
disengage. Cruise control may be reengaged when road
conditions allow. SeeCruise Control on page 3-9.
The TCS operates in all transmission shift lever
positions. But the system can upshift the transmission
only as high as the shift lever position chosen, so
use the lower gears only when necessary. See
Automatic Transmission Operation on page 2-24.
When the system is on,
this warning light comes
on and stays on if there is
a problem.
A SERVICE TRACTION CONTROL message also
appears on the DIC. When this warning light is on, the
system will not limit wheel spin. Adjust your driving
accordingly. SeeDIC Warnings and Messages
on page 3-49for more information.
To limit wheel spin, especially in slippery road
conditions, TCS should always be left on. But the
system can be turned off if needed.
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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. These
problems can be avoided by braking — if you can stop
in time. But sometimes you cannot stop in time
because there is no room. That is the time for evasive
action — steering around the problem.
The vehicle can perform very well in emergencies like
these. First apply the brakes — but, unless the
vehicle has antilock brakes, not enough to lock the
wheels. SeeBraking on page 4-4. It is better to remove
as much speed as possible from a 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 holding the steering wheel at the
recommended 9 and 3 o’clock positions, it can be turned
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
The vehicle’s right wheels can drop off the edge of a
road onto the shoulder while 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 the vehicle straddles the edge of the
pavement. Turn the steering wheel 3 to 5 inches, 8 to
13 cm, (about one-eighth turn) until the right front
tire contacts the pavement edge. Then turn the steering
wheel to go straight down the roadway.
Passing
Passing another vehicle on a two-lane road can be
dangerous. To reduce the risk of danger while passing:
Look down the road, to the sides, and to crossroads
for situations that might affect a successful pass. If
in doubt, wait.
Watch for traffic signs, pavement markings, and
lines that could indicate a turn or an intersection.
Never cross a solid or double-solid line on your side
of the lane.
Do not get too close to the vehicle you want to
pass. Doing so can reduce your visibility.
Wait your turn to pass a slow vehicle.
When you are being passed, ease 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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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 the vehicle’s three
control systems. In the braking skid, the 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.
If the 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,
the 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, 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 reducing vehicle speed by shifting to a lower
gear. Any sudden changes could cause the tires to
slide. You may not realize the surface is slippery until
the 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.
If the vehicle has the Antilock Brake System (ABS),
remember: It helps avoid only the braking skid. If
the vehicle does 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.
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Driving in Rain and on Wet Roads
Rain and wet roads can reduce vehicle traction
and affect your ability to stop and accelerate. Always
drive slower in these types of driving conditions
and avoid driving through large puddles and
deep-standing or owing water.
{CAUTION:
Wet brakes can cause crashes. They might not
work as well in a quick stop and could cause
pulling to one side. You could lose control of the
vehicle.
After driving through a large puddle of water or a
car/vehicle wash, lightly apply the brake pedal until
the brakes work normally.
Flowing or rushing water creates strong forces.
Driving through owing water could cause your
vehicle to be carried away. If this happens, you
and other vehicle occupants could drown. Do not
ignore police warnings and be very cautious about
trying to drive through owing water.
Hydroplaning
Hydroplaning is dangerous. Water can build up under
your vehicle’s tires so they actually ride on the
water. This can happen if the road is wet enough and
you are going fast enough. When your vehicle is
hydroplaning, it has little or no contact with the road.
There is no hard and fast rule about hydroplaning. The
best advice is to slow down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet weather driving tips
include:
Allow extra following distance.
Pass with caution.
Keep windshield wiping equipment in good shape.
Keep the windshield washer uid reservoir lled.
Have good tires with proper tread depth. SeeTires
on page 5-53.
Turn off cruise control.
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Hill and Mountain Roads
Driving on steep hills or through mountains is different
than driving on at or rolling terrain. Tips for driving
in these conditions include:
Keep the vehicle serviced and in good shape.
Check all uid levels and brakes, tires, cooling
system, and transmission.
Going down steep or long hills, shift to a
lower gear.
{CAUTION:
If you do not shift down, the brakes could get so
hot that they would not work well. You would then
have poor braking or even none going down a hill.
You could crash. Shift down to let the engine
assist the brakes on a steep downhill slope.
{CAUTION:
Coasting downhill in N (Neutral) or with the ignition
off is dangerous. The brakes will have to do all the
work of slowing down and they could get so hot
that they would not work well. You would then
have poor braking or even none going down a hill.
You could crash. Always have the engine running
and the vehicle in gear when going downhill.
Stay in your own lane. Do not swing wide or cut
across the center of the road. Drive at speeds
that let you stay in your own lane.
Top of hills: Be alert — something could be in your
lane (stalled car, accident).
Pay attention to special road signs (falling rocks
area, winding roads, long grades, passing or
no-passing zones) and take appropriate action.
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