traction control CHEVROLET EXPRESS 2004 Owners Manual

Windshield Washer
L(Washer Fluid):There is a paddle marked with the
windshield washer symbol at the top of the multifunction
lever. To spray washer uid on the windshield, push
the paddle. The wipers will clear the window and then
either stop or return to your preset speed.
{CAUTION:
In freezing weather, do not use your washer
until the windshield is warmed. Otherwise the
washer uid can form ice on the windshield,
blocking your vision.
Cruise Control
If your vehicle has cruise control, you can maintain a
speed of about 25 mph (40 km/h) or more without
keeping your foot on the accelerator. This can really
help on long trips. Cruise control does not work at
speeds below about 25 mph (40 km/h).
If you apply your brakes, the cruise control will
disengage.
{CAUTION:
Cruise control can be dangerous where you
cannot drive safely at a steady speed. So, do
not use your cruise control on winding roads
or in heavy traffic.
Cruise control can be dangerous on slippery
roads. On such roads, fast changes in tire
traction can cause needless wheel spinning,
and you could lose control. Do not use cruise
control on slippery roads.
3-10

The anti-lock system 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: Anti-lock 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 anti-lock brakes.
Using Anti-Lock
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 anti-lock, 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.
4-7

StabiliTrak®System
If your vehicle has StabiliTrak®, it combines anti-lock
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 that it is working properly. You may hear orfeel 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
2 miles (3.2 km) of driving before the system initializes.
The following chart describes the StabiliTrak
®not
ready light and the StabiliTrak®indicator light.
StabiliTrak®Not Ready Light StabiliTrak®Indicator Light Meaning
Off OffStabiliTrak®is enabled, but not active.
The traction control is not active.
Off FlashingStabiliTrak
®is active, or the traction control
is active.
Off OnStabiliTrak
®is disabled due to system fault.
When on after restarting, the vehicle needs
to be serviced.
On OffStabiliTrak
®is disabled due to system
initialization or the driver has disabled with
switch.
On FlashingStabiliTrak
®is not initialized and not
disabled.
The traction control is active.
For more information, seeStabiliTrak Not Ready Light on page 3-30andStabiliTrak Indicator Light on page 3-31.
4-8

Pressing and holding the
StabiliTrak®button located
on the instrument panel
for more than ve seconds
can turn off StabiliTrak
®
and part of the traction
control system.
For your safety, the system can only be disabled when
the vehicle speed is less than 20 mph (32 km/h).
You will hear three chimes and the StabiliTrak
®not
ready light will come on.
To turn on the StabiliTrak
®system, press the
StabiliTrak®button again. StabiliTrak®will automatically
turn back on when the vehicle speed exceeds 20 mph
(32 km/h). You will hear one chime and the StabiliTrak
®
not ready light will turn off.
When the StabiliTrak
®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. SeeIf You Are Stuck: In Sand, Mud,
Ice or Snow on page 4-28.
StabiliTrak®System Operation
The StabiliTrak®system is normally on, except when
the system is initializing or has been disabled with
the StabiliTrak
®button. The StabiliTrak®system will
automatically activate to assist the driver in maintaining
vehicle directional control in most driving conditions.
When activated, the StabiliTrak
®system may reduce
engine power to the wheels and apply braking to
individual wheels as necessary to assist the driver with
vehicle directional control. If your vehicle is in cruise
control when the system activates, the StabiliTrak
®
indicator light on the instrument panel will ash, and the
cruise control will automatically disengage. When the
StabiliTrak
®system is no longer active, you may
re-engage the cruise control. SeeCruise Control on
page 3-10.
The StabiliTrak
®system 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.
4-9

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.
If the brake-traction control system activates constantly
or if the brakes have heated up due to high speed
braking, the brake-traction control will be automatically
disabled. The system will come back on after the
brakes have cooled. This can take up to two minutes or
longer depending on brake usage.
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.
Steering
Power Steering
If you lose power steering assist because the engine
stops or the system is not functioning, you can steer but
it will take much more effort.
Steering Tips
Driving on Curves
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.
What should you do if this ever happens? Ease up on
the accelerator pedal, steer the vehicle the way you
want it to go, and slow down.
4-10

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.
A cornering skid is best handled by easing your foot off
the accelerator pedal.If your 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,
your 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, you
will want to 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 engine braking by shifting to a
lower gear. Any sudden changes could cause the tires
to slide. You may not realize the surface is slippery
until your 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.
Remember: Any anti-lock brake system (ABS) helps
avoid only the braking skid.
4-14

{CAUTION:
Mixing tires could cause you to lose control
while driving. If you mix tires of different sizes
or types (radial and bias-belted tires) the
vehicle may not handle properly, and you
could have a crash. Using tires of different
sizes may also cause damage to your vehicle.
Be sure to use the same size and type tires on
all wheels.
{CAUTION:
If you use bias-ply tires on your vehicle, the
wheel rim anges could develop cracks after
many miles of driving. A tire and/or wheel
could fail suddenly, causing a crash. Use only
radial-ply tires with the wheels on your vehicle.
Uniform Tire Quality Grading
Quality grades can be found where applicable on the
tire sidewall between tread shoulder and maximum
section width. For example:
Treadwear 200 Traction AA Temperature A
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration, which grades tires by
treadwear, traction and temperature performance. (This
applies only to vehicles sold in the United States.)
The grades are molded on the sidewalls of most
passenger car tires. The Uniform Tire Quality Grading
system does not apply to deep tread, winter-type
snow tires, space-saver or temporary use spare tires,
tires with nominal rim diameters of 10 to 12 inches
(25 to 30 cm), or to some limited-production tires.
While the tires available on General Motors passenger
cars and light trucks may vary with respect to these
grades, they must also conform to federal safety
requirements and additional General Motors Tire
Performance Criteria (TPC) standards.
5-63

Treadwear
The treadwear grade is a comparative rating based on
the wear rate of the tire when tested under controlled
conditions on a specied government test course.
For example, a tire graded 150 would wear one and
a half (1.5) times as well on the government course as
a tire graded 100. The relative performance of tires
depends upon the actual conditions of their use,
however, and may depart signicantly from the norm
due to variations in driving habits, service practices and
differences in road characteristics and climate.
Traction – AA, A, B, C
The traction grades, from highest to lowest, are AA, A,
B, and C. Those grades represent the tire’s ability
to stop on wet pavement as measured under controlled
conditions on specied government test surfaces of
asphalt and concrete. A tire marked C may have poor
traction performance. Warning: The traction grade
assigned to this tire is based on straight-ahead braking
traction tests, and does not include acceleration,
cornering, hydroplaning, or peak traction characteristics.
Temperature – A, B, C
The temperature grades are A (the highest), B, and C,
representing the tire’s resistance to the generation
of heat and its ability to dissipate heat when tested
under controlled conditions on a specied indoorlaboratory test wheel. Sustained high temperature can
cause the material of the tire to degenerate and
reduce tire life, and excessive temperature can lead to
sudden tire failure. The grade C corresponds to a
level of performance which all passenger car tires must
meet under the Federal Motor Vehicle Safety Standard
No. 109. Grades B and A represent higher levels of
performance on the laboratory test wheel than the
minimum required by law.
Warning: The temperature grade for this tire is
established for a tire that is properly inated and not
overloaded. Excessive speed, underination, or
excessive loading, either separately or in combination,
can cause heat buildup and possible tire failure.
Wheel Alignment and Tire Balance
The wheels on your vehicle were aligned and balanced
carefully at the factory to give you the longest tire life
and best overall performance.
If you notice unusual tire wear or your vehicle pulling
one way or the other, the alignment may need to
be reset. If you notice your vehicle vibrating when
driving on a smooth road, your wheels may need to
be rebalanced.
5-64

Used Replacement Wheels
{CAUTION:
Putting a used wheel on your vehicle is
dangerous. You can’t know how it’s been used
or how far it’s been driven. It could fail
suddenly and cause a crash. If you have to
replace a wheel, use a new GM original
equipment wheel.
Tire Chains
{CAUTION:
If your vehicle has dual wheels or P235/75R16
or LT245/75R16 size tires, do not use tire
chains. They can damage your vehicle because
there’s not enough clearance. Tire chains used
CAUTION: (Continued)
CAUTION: (Continued)
on a vehicle without the proper amount of
clearance can cause damage to the brakes,
suspension or other vehicle parts. The area
damaged by the tire chains could cause you to
lose control of your vehicle and you or others
may be injured in a crash.
Use another type of traction device only if its
manufacturer recommends it for use on your
vehicle and tire size combination and road
conditions. Follow that manufacturer’s
instructions. To help avoid damage to your
vehicle, drive slowly, readjust or remove the
device if it’s contacting your vehicle, and don’t
spin your wheels.
If you do nd traction devices that will t,
install them on the rear tires.
5-66

Traction
Stabilitrak®System........................................ 4-8
Transmission
Fluid, Automatic...........................................5-19
Transmission Operation, Automatic....................2-22
Trip Odometer................................................3-24
Turn and Lane-Change Signals.......................... 3-8
Turn Signal/Multifunction Lever........................... 3-7
U
Understanding Radio Reception........................3-72
Uniform Tire Quality Grading............................5-63
V
Vehicle
Control........................................................ 4-5
Damage Warnings........................................... iv
Symbols......................................................... iv
Vehicle Data Collection and Event Data
Recorders.................................................... 7-9
Vehicle Identication
Number (VIN).............................................5-91
Service Parts Identication Label...................5-91
Ventilation Adjustment......................................3-20
Visors...........................................................2-17
Voltmeter Gage..............................................3-28
W
Warning Lights, Gages and Indicators................3-22
Warnings
Hazard Warning Flashers............................... 3-6
Other Warning Devices.................................. 3-6
Safety and Symbols......................................... iii
Vehicle Damage.............................................. iv
Wheels
Alignment and Tire Balance..........................5-64
Replacement...............................................5-65
Where to Put the Restraint...............................1-42
Windows.......................................................2-15
Manual......................................................2-15
Power........................................................2-16
Swing-Out Windows.....................................2-17
Windshield
Wiper Blades, Cleaning................................5-87
Windshield Washer.........................................3-10
Fluid..........................................................5-33
Windshield Wiper
Blade Replacement......................................5-51
Fuses........................................................5-92
Windshield Wipers......................................... 3-9
Winter Driving................................................4-24
Y
Your Vehicle and the Environment....................... 6-2
12