CHEVROLET AVALANCHE 2004 1.G Repair Manual

The right front passenger’s frontal air bag is in the
instrument panel on the passenger’s side.If your vehicle has one, the driver’s side impact air bag is
in the side of the driver’s seatback closest to the door.
1-55

If your vehicle has one, the right front passenger’s side
impact air bag is in the side of the passenger’s
seatback closest to the door.
{CAUTION:
If something is between an occupant and an
air bag, the bag might not inate properly or it
might force the object into that person causing
severe injury or even death. The path of an
inating air bag must be kept clear. Do not put
anything between an occupant and an air bag,
and do not attach or put anything on the
steering wheel hub or on or near any other air
bag covering. Do not let seat covers block the
ination path of a side impact air bag.
1-56

When Should an Air Bag Inate?
Frontal Air Bags
The driver’s and right front passenger’s frontal air bags
are designed to inate in moderate to severe frontal or
near-frontal crashes. But they are designed to inate only
if the impact speed is above the system’s designed
“threshold level.”
In addition, your vehicle has “dual stage” frontal air
bags, which adjust the amount of restraint according to
crash severity. For moderate frontal impacts, these
air bags inate at a level less than full deployment.
For more severe frontal impacts, full deployment occurs.
If the front of your vehicle goes straight into a wall
that doesn’t move or deform, the threshold level for
the reduced deployment is about 10 to 16 mph
(16 to 25 km/h), and the threshold level for a full
deployment is about 20 to 25 mph (32 to 40 km/h).
The threshold level can vary, however, with specic
vehicle design, so that it can be somewhat above
or below this range.If your vehicle strikes something that will move or
deform, such as a parked car, the threshold level will be
higher. The driver’s and right front passenger’s frontal
air bags are not designed to inate in rollovers, rear
impacts, or in many side impacts because ination
would not help the occupant.
Seat Position Sensors
Vehicles with dual stage air bags are also equipped
with special sensors which enable the sensing system
to monitor the position of both the driver and passenger
front seats. The seat position sensor provides
information which is used to determine if the air bags
should deploy at a reduced level or at full deployment.
1-57

Side Impact Air Bags
Your vehicle may or may not have a side impact air
bag. SeeAir Bag Systems on page 1-51. Side impact
air bags are designed to inate in moderate to severe
side crashes. A side impact air bag will inate if the
crash severity is above the system’s designed “threshold
level.” The threshold level can vary with specic
vehicle design. Side impact air bags are not designed to
inate in frontal or near-frontal impacts, rollovers or
rear impacts, because ination would not help the
occupant. A side impact air bag will only deploy on the
side of the vehicle that is struck.
Air Bag Systems
In any particular crash, no one can say whether an air
bag should have inated simply because of the damage
to a vehicle or because of what the repair costs were.
For frontal air bags, ination is determined by the angle
of the impact and how quickly the vehicle slows down
in frontal and near-frontal impacts. For side impact
air bags, ination is determined by the location
and severity of the impact.
The air bag system is designed to work properly under
a wide range of conditions, including off-road usage.
Observe safe driving speeds, especially on rough
terrain. As always, wear your safety belt. See Off-Road
Driving with Your Four-Wheel Drive Vehicle in the
Index for tips on off-road driving.
1-58

What Makes an Air Bag Inate?
In an impact of sufficient severity, the air bag sensing
system detects that the vehicle is in a crash. For
both frontal and side impact air bags, the sensing
system triggers a release of gas from the inator, which
inates the air bag. The inator, the air bag and
related hardware are all part of the air bag modules.
Frontal air bag modules are located inside the steering
wheel and instrument panel. For vehicles with side
impact air bags, the air bag modules are located in the
seatback closest to the driver’s and/or right front
passenger’s door.
How Does an Air Bag Restrain?
In moderate to severe frontal or near frontal collisions,
even belted occupants can contact the steering wheel
or the instrument panel. In moderate to severe side
collisions, even belted occupants can contact the inside
of the vehicle. The air bag supplements the protection
provided by safety belts. Air bags distribute the force of
the impact more evenly over the occupant’s upper
body, stopping the occupant more gradually. But the
frontal air bags would not help you in many types
of collisions, including rollovers, rear impacts, and many
side impacts, primarily because an occupant’s motion
is not toward the air bag. Side impact air bags would not
help you in many types of collisions, including frontal
or near frontal collisions, rollovers, and rear impacts,
primarily because an occupant’s motion is not toward
those air bags. Air bags should never be regarded
as anything more than a supplement to safety belts, and
then only in moderate to severe frontal or near-frontal
collisions for the driver’s and right front passenger’s
frontal air bags, and only in moderate to severe
side collisions for vehicles with a driver’s and right front
passenger’s side impact air bag.
1-59

What Will You See After an
Air Bag Inates?
After the air bag inates, it quickly deates, so quickly
that some people may not even realize the air bag
inated. Some components of the air bag module will be
hot for a short time. These components include the
steering wheel hub for the driver’s frontal air bag and the
instrument panel for the right front passenger’s frontal
air bag. For vehicles with side impact air bags, the side
of the seatback closest to the driver’s and/or right
front passenger’s door will be hot. The parts of the bag
that come into contact with you may be warm, but
not too hot to touch. There will be some smoke and dust
coming from the vents in the deated air bags. Air bag
ination doesn’t prevent the driver from seeing or
being able to steer the vehicle, nor does it stop people
from leaving the vehicle.
{CAUTION:
When an air bag inates, there is dust in the air.
This dust could cause breathing problems for
people with a history of asthma or other
breathing trouble. To avoid this, everyone in the
vehicle should get out as soon as it is safe to do
so. If you have breathing problems but can not
get out of the vehicle after an air bag inates,
then get fresh air by opening a window or a
door. If you experience breathing problems
following an air bag deployment, you should
seek medical attention.
1-60

In many crashes severe enough to inate an air bag,
windshields are broken by vehicle deformation.
Additional windshield breakage may also occur from the
right front passenger air bag.
Air bags are designed to inate only once. After an
air bag inates, you’ll need some new parts for your
air bag system. If you don’t get them, the air bag
system won’t be there to help protect you in another
crash. A new system will include air bag modules
and possibly other parts. The service manual for your
vehicle covers the need to replace other parts.
Your vehicle is equipped with electronic frontal
sensors which help the sensing system distinguish
between a moderate and a more severe frontal
impact. Your vehicle is also equipped with a crash
sensing and diagnostic module, which records
information about the frontal air bag system.
The module records information about the readiness
of the system and when the system commands air
bag ination. It records the status of the driver’s
safety belt usage in a crash in which the air bag
deploys or a crash in which the air bag nearly
deploys. The module also records speed, engine
rpm, brake and throttle data.
Let only qualied technicians work on your air bag
systems. Improper service can mean that an air bag
system won’t work properly. See your dealer for
service.
Notice:If you damage the covering for the driver’s
or the right front passenger’s air bag, or the air
bag covering on the driver’s and right front
passenger’s seatback, the air bag may not work
properly. You may have to replace the air bag
module in the steering wheel, both the air bag
module and the instrument panel for the right front
passenger’s air bag, or both the air bag module
and seatback for the driver’s and right front
passenger’s side impact air bag. Do not open or
break the air bag coverings.
1-61

Passenger Sensing System
If your rearview mirror has one of the indicators pictured
in the following illustrations, your vehicle has a
passenger sensing system. The indicator will be visible
when you turn your ignition key to START or RUN.
The words ON and OFF or the symbol for on and off,
will be visible on the rearview mirror during the system
check. When the system check is complete, either
the word ON or the word OFF, or the symbol for on or
the symbol for off will be visible. SeePassenger Air
Bag Status Indicator on page 3-38. If your rearview
mirror does not have either of the indicators pictured,
then your vehicle does not have the passenger
sensing system.The passenger sensing system will turn off the right
front passenger’s frontal air bag under certain
conditions. The driver’s air bag and the side air bags
are not part of the passenger sensing system.
The passenger sensing system works with sensors that
are part of the right front passenger’s seat and safety
belt. The sensors are designed to detect the presence
of a properly-seated occupant and determine if the
passenger’s frontal air bag should be enabled
(may inate) or not.
Accident statistics show that children are safer if they
are restrained in the rear rather than the front seat.
General Motors recommends that child restraints
be secured in a rear seat, including an infant riding in a
rear-facing infant seat, a child riding in a forward-facing
child seat and an older child riding in a booster seat.
Your vehicle has a rear seat that will accommodate
a rear-facing child restraint. A label on your sun visor
says, “Never put a rear-facing child seat in the
front.” This is because the risk to the rear-facing child is
so great, if the air bag deploys. Passenger Air Bag Status Indicator – United States
Passenger
Air Bag Status
Indicator – Canada
1-62

{CAUTION:
A child in a rear-facing child restraint can be
seriously injured or killed if the right front
passenger’s air bag inates. This is because
the back of the rear-facing child restraint
would be very close to the inating air bag.
Even though the passenger sensing system is
designed to turn off the passenger’s frontal air
bag if the system detects a rear-facing child
restraint, no system is fail-safe, and no one
can guarantee that an air bag will not deploy
under some unusual circumstance, even
though it is turned off. General Motors
recommends that rear-facing child restraints
be secured in the rear seat, even if the air bag
is off.The passenger sensing system is designed to turn off
the right front passenger’s frontal air bag if:
the right front passenger seat is unoccupied
the system determines that an infant is present in a
rear-facing infant seat
the system determines that a small child is present
in a forward-facing child restraint
the system determines that a small child is present
in a booster seat
a right front passenger takes his/her weight off of
the seat for a period of time
the right front passenger seat is occupied by a
smaller person, such as a child who has outgrown
child restraints
or if there is a critical problem with the air bag
system or the passenger sensing system.
When the passenger sensing system has turned off the
passenger’s frontal air bag, the off indicator will light
and stay lit to remind you that the air bag is off.
If a child restraint has been installed and the on indicator
is lit, turn the vehicle off. Remove the child restraint from
the vehicle and reinstall the child restraint following the
child restraint manufacturer’s directions and refer to
Securing a Child Restraint in the Right Front Seat
Position on page 1-47.
1-63

If after reinstalling the child restraint and restarting the
vehicle, the on indicator is still lit, check to make
sure that the vehicle’s seatback is not pressing the child
restraint into the seat cushion. If this happens, slightly
recline the vehicle’s seatback and adjust the seat
cushion if possible. Also make sure the child restraint is
not trapped under the vehicle head restraint. If this
happens, adjust the head restraint.
If the on indicator is still lit, secure the child in the child
restraint in a rear seat position in the vehicle and
check with your dealer.
The passenger sensing system is designed to enable
(may inate) the right front passenger’s frontal air
bag anytime the system senses that a person of adult
size is sitting properly in the right front passenger’s seat.
When the passenger sensing system has allowed the
air bag to be enabled, the on indicator will light and stay
lit to remind you that the air bag is active.
For some children who have outgrown child restraints
and for very small adults, the passenger sensing system
may or may not turn off the right front passenger’s
frontal air bag, depending upon the person’s seating
posture and body build. Everyone in your vehicle
who has outgrown child restraints should wear a safety
belt properly — whether or not there is an air bag
for that person.If a person of adult-size is sitting in the right front
passenger’s seat, but the off indicator is lit, it could be
because that person is not sitting properly in the seat. If
this happens, turn the vehicle off and ask the person to
place the seatback in the fully upright position, then sit
upright in the seat, centered on the seat cushion, with the
person’s legs comfortably extended. Restart the vehicle
and have the person remain in this position for about two
minutes. This will allow the system to detect that person
and then enable the passenger’s air bag.
1-64