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.
SeeStabiliTrak
®System on page 384.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modi cations on page 488.
Braking
SeeBrake System Warning Light on page 258.
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
Modi cations on page 488.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 259.
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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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.
If the system fails to turn on or activate, the
StabiliTrak
®light along with one of the following
messages will be displayed on the Driver
Information Center (DIC): TRACTION CONTROL
OFF, SERVICE TRACTION CONTROL,
STABILITRAK OFF, SERVICE STABILITRAK.If these DIC messages appear, make sure the
StabiliTrak
®system has not been turned off using
the StabiliTrak®on/off button. Then turn the
steering wheel clockwise from the nine o’clock
position to the three o’clock position. If this clears
the message(s), your vehicle does not need
servicing. If this does not clear the message(s),
then turn the vehicle off, wait 15 seconds, and then
turn it back on again to reset the system. If any
of these messages still appear on the Driver
Information Center (DIC), your vehicle should be
taken in for service. For more information on
the DIC messages, seeDriver Information
Center (DIC) on page 269.
The StabiliTrak
®light
will ash on the
instrument panel cluster
when the system is
both on and activated.
You may also feel or hear the system working;
this is normal.
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The traction control
disable button is located
on the instrument
panel below the climate
controls.
The traction control part of StabiliTrak
®can be
turned off by pressing and releasing the
StabiliTrak
®button if both systems (traction control
and StabiliTrak®) were previously on. To disable
both traction control and StabiliTrak®, press
and hold the button for ve seconds.
Traction control and StabiliTrak
®can be turned on
by pressing and releasing the StabiliTrak®button if
not automatically shut off for any other reason.
When the TCS or StabiliTrak
®system is turned off,
the StabiliTrak®light and the appropriate TCS
off or StabiliTrak®off message will be displayed on
the DIC to warn the driver. Your vehicle will still
have brake-traction control when traction control is
off, but will not be able to use the engine speed
management system. See “Traction Control
Operation” next for more information.When the traction control system has been turned
off, you may still hear system noises as a result
of the brake-traction control coming on.
It is recommended to leave the system on for
normal driving conditions, but it may be necessary
to turn the system off if your vehicle is stuck in
sand, mud, ice or snow, and you want to
“rock” your vehicle to attempt to free it. It may also
be necessary to turn off the system when driving
in extreme off-road conditions where high
wheel spin is required. SeeIf Your Vehicle is
Stuck in Sand, Mud, Ice, or Snow on page 424.
When the transfer case is in 4LO, the stability
system is automatically disabled, the StabiliTrak
®
light will come on and the STABILITRAK OFF
message will appear on the DIC. Both traction
control and StabiliTrak
®are automatically disabled
in this condition.
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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 220.
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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