2007 CHEVROLET TAHOE 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. See
StabiliTrak
®System on page 363.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modications on page 444.
Braking
SeeBrake System Warning Light on page 249.
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.
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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 444.
Anti-Lock Brake System (ABS)
Your vehicle has the Anti-Lock Brake System
(ABS), an advanced electronic braking system that
will help prevent a braking skid.
When you start your engine and begin to drive
away, ABS will check itself. You may hear a
momentary motor or clicking noise while this test
is going on. This is normal.If there is a problem
with ABS, this warning
light will stay on.
SeeAnti-Lock Brake
System Warning
Light on page 251.
Along with ABS, your vehicle has a Dynamic Rear
Proportioning (DRP) system. If there is a DRP
problem, both the brake and ABS warning lights
will come on accompanied by a 10-second
chime. The lights and chime will come on each
time the ignition is turned on until the problem is
repaired. See your dealer for service.
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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
front wheel and at both rear wheels.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 the brakes vibrate, or you may notice
some noise, 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.
Locking Rear Axle
If your vehicle has this feature, your locking rear
axle can give you additional traction on snow, mud,
ice, sand or gravel. It works like a standard axle
most of the time, but when one of the rear wheels
has no traction and the other does, this feature will
allow the wheel with traction to move the vehicle.
StabiliTrak®System
Your vehicle may be equipped with the
StabiliTrak®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). In some cases, it may
take approximately two miles of driving before the
system initializes.
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Traction Control Operation
The traction control system is part of the
StabiliTrak®system. Traction control limits wheel
spin by reducing engine power to the wheels
(engine speed management) and by applying
brakes to each individual wheel (brake-traction
control) as necessary.
The traction control system is enabled
automatically when you start your vehicle. It will
activate and the StabiliTrak
®light will ash if
it senses that any of the wheels are spinning or
beginning to lose traction while driving. If you turn
off traction control, only the brake-traction
control portion of traction control will work. The
engine speed management will be disabled. In this
mode, engine power is not reduced automatically
and the driven wheels can spin more freely.
This can cause the brake-traction control to
activate constantly.Notice:If you allow the wheel(s) of one axle to
spin excessively while the StabiliTrak
®, ABS
and brake warning lights and the SERVICE
STABILITRAK message are displayed, you
could damage the transfer case. The repairs
would not be covered by your warranty. Reduce
engine power and do not spin the wheel(s)
excessively while these lights and this message
are displayed.
The traction control system may activate on
dry or rough roads or under conditions such as
heavy acceleration while turning or abrupt upshifts/
downshifts of the transmission. When this happens,
you may notice a reduction in acceleration, or may
hear a noise or vibration. This is normal.
If your vehicle is in cruise control when the system
activates, the StabiliTrak
®light will ash and the
cruise control will automatically disengage. When
road conditions allow you to use cruise again, you
may re-engage the cruise control. SeeCruise
Control on page 211.
StabiliTrak
®may also turn off automatically if it
determines that a problem exists with the system. If
the problem does not clear itself after restarting the
vehicle, you should see your dealer for service.
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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 444.
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 the brakes. SeeBraking
on page 360. 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.An emergency like this requires close attention
and a quick decision. If you are holding the
steering wheel at the recommended 9 and
3 o’clock positions, you can turn it 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.
368

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 that,
if your 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.
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 your
vehicle’s three control systems. In the braking skid,
your 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.
371

Q:Suppose, after stalling, I try to back down
the hill and decide I just cannot do it. What
should I do?
A:Set the parking brake, put your transmission
in PARK (P) and turn off the engine. Leave
the vehicle and go get some help. Exit on the
uphill side and stay clear of the path the
vehicle would take if it rolled downhill. Do not
shift the transfer case to NEUTRAL when
you leave the vehicle. Leave it in some gear.
Driving Downhill
When off-roading takes you downhill, you will want
to consider a number of things:
How steep is the downhill? Will I be able to
maintain vehicle control?
What is the surface like? Smooth? Rough?
Slippery? Hard-packed dirt? Gravel?
Are there hidden surface obstacles? Ruts?
Logs? Boulders?
What is at the bottom of the hill? Is there a
hidden creek bank or even a river bottom
with large rocks?
If you decide you can go down a hill safely, then
try to keep your vehicle headed straight down, and
use a low gear. This way, engine drag can help
your brakes and they will not have to do all
the work. Descend slowly, keeping your vehicle
under control at all times.
{CAUTION:
Heavy braking when going down a hill can
cause your brakes to overheat and fade.
This could cause loss of control and a
serious accident. Apply the brakes lightly
when descending a hill and use a low
gear to keep vehicle speed under control.
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