2004 CHEVROLET AVALANCHE engine

STABILITY SYS ACTIVE
You may see the STABILITY SYS ACTIVE message on
the DIC. It means that an advanced computer-controlled
system has come on to help your vehicle continue to
go in the direction in which you’re steering.
For more information on the Stabilitrak
®system, see
Stabilitrak®System on page 4-11.
SERVICE STABILITY
If you ever see the SERVICE STABILITY message, it
means there may be a problem with your
Stabilitrak
®system. If you see this message try to reset
the system (stop; turn off the engine; then start the
engine again). If the SERVICE STABILITY message still
comes on, it means there is a problem. You should
see your dealer for service. The vehicle is safe to drive,
however, you do not have the benet of Stabilitrak
®,
so reduce your speed and drive accordingly.
For more information on the Stabilitrak
®system, see
Stabilitrak®System on page 4-11.
STABILITY SYS DISABLED
The STABILITY SYS DISABLED message will turn on
when you press the Stabilitrak®button, or when the
stability control has been automatically disabled. There
are four conditions that can cause this message to
appear. One condition is overheating, which could occur
if Stabilitrak
®activates continuously for an extended
period of time. The message will also be displayed if the
brake system warning light is on. SeeBrake System
Warning Light on page 3-42Brake System Warning
Light. The message could be displayed if the stability
system takes longer than usual to complete its
diagnostic checks due to driving conditions. Also, if an
engine or vehicle related problem has been detected,
and the vehicle needs service, the message will appear.
The message will turn off as soon as the conditions
that caused the message to be displayed are no longer
present.
For more information on the Stabilitrak
®system, see
Stabilitrak®System on page 4-11.
3-71

CHECK TIRE PRESSURE
If a low tire pressure is detected in any of the vehicle’s
tires, this message will appear on the DIC. Press
the select button or trip stem to acknowledge the
message and clear it from the DIC display.
SeeTires on page 5-68for more information on tires
and the correct ination pressures.
This message will appear at each ignition cycle until the
tires are inated to the correct ination pressure.
SERVICE TIRE MONITOR
This message will be displayed if any of the tire monitor
sensors have malfunctioned, or if the tire monitor
sensors have not been programmed correctly. For more
information on programming the tire pressure monitor
system seeTire Pressure Monitor System on page 5-77.
Press the select button to acknowledge the message
and clear it from the DIC display.
This message will appear at each ignition cycle until the
tire pressure monitor system has been serviced.
Audio System(s)
Notice:Before adding any sound equipment to your
vehicle, like a tape player, CB radio, mobile
telephone, or two-way radio, make sure that it can be
added by checking with your dealer. Also, check
federal rules covering mobile radio and telephone
units. If sound equipment can be added, it is very
important to do it properly. Added sound equipment
may interfere with the operation of your vehicle’s
engine, radio, or other systems, and even damage
them. Your vehicle’s systems may interfere with the
operation of sound equipment that has been added
improperly.
Figure out which audio system is in your vehicle, nd
out what your audio system can do, and how to operate
all of its controls.
Your vehicle may have a feature called Retained
Accessory Power (RAP). With RAP, the audio system
can be played even after the ignition is turned off.
See “Retained Accessory Power (RAP)” underIgnition
Positions on page 2-31.
3-72

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. Your brakes may not have time to cool between
hard stops. Your 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 engine ever stops while you are driving, brake
normally but do not pump your brakes. If you do,
the pedal may get harder to push down. If your 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.Anti-lock Brake System
Your vehicle has anti-lock brakes. ABS is an advanced
electronic braking system that will help prevent a
braking skid.
When you start your engine and begin to drive away,
your anti-lock brake system 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
the anti-lock brake system,
this warning light will
stay on. SeeAnti-Lock
Brake System Warning
Light on page 3-43.
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.
4-7

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.
Traction Assist System (TAS)
Your vehicle may have a Traction Assist System (TAS)
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 rear wheels are
spinning or beginning to lose traction. When this
happens, the system reduces engine power to limit
wheel spin.The TRACTION ACTIVE message will come on in the
DIC when the TAS is limiting wheel spin. SeeDIC
Warnings and Messages on page 3-65.
You may hear or feel the system working or notice a
lack of accelerator response, but this is normal.
The Traction Assist System may operate on dry roads
under some conditions. When this happens, you
may notice a reduction in acceleration. This is normal
and doesn’t mean there’s a problem with your vehicle.
Examples of these conditions include a hard
acceleration in a turn, an abrupt upshift or downshift of
the transmission or driving on rough roads.
If your vehicle is in cruise control when the TAS begins
to limit wheel spin, the cruise control will automatically
disengage. When road conditions allow you to safely
use it again, you may re-engage the cruise control. See
Cruise ControlunderTurn Signal/Multifunction Lever
on page 3-8.
4-9

When the traction off light
is on, the TAS is off and
will not limit wheel
spin. Adjust your driving
accordingly.
The traction off light will come on under the following
conditions:
The Traction Assist System is turned off, either by
pressing the TAS on/off button or turning off the
automatic engagement feature of the TAS.
The transmission is in FIRST (1); TAS will not
operate in this gear. This is normal.
The vehicle is driven on an extremely rough road.
When the vehicle leaves the rough surface, slows
down or stops, the light will go off and TAS will
be on again. This is normal.
A Traction Assist System, Anti-Lock Brake System
or engine-related problem has been detected and
the vehicle needs service.
SeeTraction Off Light on page 3-44.
The Traction Assist System, as delivered from the
factory, will automatically come 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 TAS off if you ever need
to. You should turn the TAS off if your vehicle ever
gets stuck in sand, mud or snow and rocking the vehicle
is required. SeeIf You Are Stuck: In Sand, Mud, Ice
or Snow on page 4-49.
To turn the system on or
off press the TAS on/off
button located on the
instrument panel.
If you used the button to turn the system off, the traction
off light will come on and stay on. You can turn the
system back on at any time by pressing the button
again. The traction off light should go off.
4-10

If desired, you can change the TAS automatic
engagement feature so that the system will not come on
automatically when the engine is started. To do so:
1. Park the vehicle with the ignition off and the
transmission in PARK (P).
2. Turn the ignition to RUN; do not start the engine.
3. Apply the brake pedal, shift into NEUTRAL (N),
press the accelerator pedal to the oor and then
press the TAS on/off button and hold it down for at
least six seconds.
4. Release the TAS button and both pedals.
5. Turn off the ignition and wait a few seconds.
The next time you start your vehicle, the TAS will not
automatically come on. You can restore the automatic
feature by using the same procedure. Whether the TAS is
set to come on automatically or not, you can always turn
the system on or off by pressing the TAS on/off button.
Locking Rear Axle
If your vehicle has this feature, it 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 Stabilitrak®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
insure 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 STABILITY
SYS DISABLED or SERVICE STABILITY message
will be displayed. If the vehicle has gone through heavy
acceleration or braking or multiple turns during the
rst two miles of driving after starting your vehicle, the
STABILITY SYS DISABLED message may appear.
If this is the case, your vehicle does not need servicing.
You will need to turn the vehicle off and then restart
it to initialize Stabilitrak
®. If either message appears on
the Driver Information Center (DIC), and your vehicle
hasn’t gone through hard acceleration, braking or
multiple turns in the rst two miles of driving, your
vehicle should be taken in for service.
4-11

The STABILITY SYS ACTIVE message will appear on
the Driver Information Center (DIC) only when the
system is both on and activated. It means that an
advanced computer-controlled system has come on to
help your vehicle continue to go in the direction in which
you’re steering. Stabilitrak
®activates when the
computer senses that your vehicle is just starting to
spin, as it might if you hit a patch of ice or other slippery
spot on the road. When the system activates, you
may hear a noise or feel a vibration in the brake pedal.
This is normal. When the STABILITY SYS ACTIVE
message is on, you should continue to steer in
the direction you want to go. The system is designed to
help you in bad weather or other difficult driving
situations by making the most of whatever road
conditions will permit. For more information on the
stability messages, seeDriver Information Center (DIC)
on page 3-53.Stabilitrak
®and part of the
traction control system can
be turned off or back on
by pressing the
Stabilitrak
®button on the
instrument panel.
When the system is turned off, the traction off light will
illuminate, and the STABILITY SYS DISABLED
message will appear on the DIC to warn the driver that
both the stability system and part of the traction
control system are disabled. Your vehicle will still have
brake-traction control when Stabilitrak
®is off, but
will not be able to use the engine speed management
system. See “Traction Control Operation” next for
more information.
4-12

When the Stabilitrak®system has been turned off you
may still hear system noises as a result of the
brake-traction control coming on.
To limit wheel spin and realize the full benets of the
stability enhancement system, you should normally
leave Stabilitrak
®on, 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 You Are Stuck: In
Sand, Mud, Ice or Snow on page 4-49.
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, and it will activate and
display the TRACTION ACTIVE message in the Driver
Information Center (DIC) if it senses that any of the
wheels are spinning or beginning to lose traction while
driving. If you turn off Stabilitrak
®, only the brake-traction
control portion of traction control will work. The engine
speed management will be disabled. In this state, engine
power is not reduced automatically and the driven wheels
can spin more freely. This can cause the brake-traction
control to activate constantly. For more information on the
traction active message, seeDriver Information Center
(DIC) on page 3-53.
Notice:If the traction off light comes on due to
heavy braking and/or because the traction control
system has been continuously active, do not
allow the wheel(s) of one axle to spin excessively. If
you do, you may be causing damage to the
transfer case. This could lead to costly repairs not
covered by your warranty.
4-13