2004 CHEVROLET AVALANCHE ECU

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

Servicing Your Air Bag-Equipped
Vehicle
Air bags affect how your vehicle should be serviced.
There air bag system parts in several places around
your vehicle. You don’t want the system to inate while
someone is working on your vehicle. Your dealer
and the service manual have information about servicing
your vehicle and the air bag system. To purchase a
service manual, seeService Publications Ordering
Information on page 7-13.
{CAUTION:
For up to 10 seconds after the ignition key is
turned off and the battery is disconnected,
an air bag can still inate during improper
service. You can be injured if you are close
to an air bag when it inates. Avoid yellow
connectors. They are probably part of the air
bag system. Be sure to follow proper service
procedures, and make sure the person
performing work for you is qualied to do so.
Air bag systems do not need regular maintenance.
Adding Equipment to Your
Air Bag-Equipped Vehicle
Q:Is there anything I might add to the front or
sides of the vehicle that could keep the air
bags from working properly?
A:Yes. If you add things that change your vehicle’s
frame, bumper system, front end or side sheet
metal or height, they may keep the air bag system
from working properly. Also, the air bag system
may not work properly if you relocate any of the air
bag sensors. If you have any questions about
this, you should contact Customer Assistance
before you modify your vehicle. The phone numbers
and addresses for Customer Assistance are in
Step Two of the Customer Satisfaction Procedure
in this manual. SeeCustomer Satisfaction
Procedure on page 7-2.
1-66

Q:Because I have a disability, I have to get my
vehicle modied. How can I nd out whether
this will affect my advanced air bag system?
A:Changing or moving any parts of the front seats,
safety belts, the air bag sensing and diagnostic
module (located under the driver’s seat), or
the inside rearview mirror can affect the operation
of the advanced air bag system. If you have
questions, call Customer Assistance. The phone
numbers and addresses for Customer Assistance
are in Step Two of the Customer Satisfaction
Procedure in this manual. SeeCustomer
Satisfaction Procedure on page 7-2.
Restraint System Check
Checking Your Restraint Systems
Now and then, make sure the safety belt reminder light
and all your belts, buckles, latch plates, retractors
and anchorages are working properly. Look for any other
loose or damaged safety belt system parts. If you see
anything that might keep a safety belt system from doing
its job, have it repaired.
Torn or frayed safety belts may not protect you in a
crash. They can rip apart under impact forces. If a belt
is torn or frayed, get a new one right away.
Also look for any opened or broken air bag covers, and
have them repaired or replaced. (The air bag system
does not need regular maintenance.)
1-67

Keys...............................................................2-3
Remote Keyless Entry System.........................2-4
Remote Keyless Entry System Operation...........2-5
Doors and Locks.............................................2-8
Door Locks....................................................2-8
Power Door Locks..........................................2-9
Delayed Locking...........................................2-10
Programmable Automatic Door Locks..............2-10
Rear Door Security Locks..............................2-13
Lockout Protection........................................2-13
Midgate.......................................................2-14
Tailgate.......................................................2-23
Windows........................................................2-25
Power Windows............................................2-26
Sun Visors...................................................2-26
Theft-Deterrent Systems..................................2-27
Content Theft-Deterrent.................................2-27
Passlock
®....................................................2-29
Starting and Operating Your Vehicle................2-30
New Vehicle Break-In....................................2-30
Ignition Positions..........................................2-31
Starting Your Engine.....................................2-32Adjustable Throttle and Brake Pedal................2-33
Engine Coolant Heater..................................2-33
Automatic Transmission Operation...................2-34
Four-Wheel Drive..........................................2-38
Parking Brake..............................................2-42
Shifting Into Park (P).....................................2-43
Shifting Out of Park (P).................................2-46
Parking Over Things That Burn.......................2-46
Engine Exhaust............................................2-47
Running Your Engine While You Are Parked. . . .2-48
Mirrors...........................................................2-49
Automatic Dimming Rearview Mirror with
OnStar
®, Compass and Temperature
Display....................................................2-49
Automatic Dimming Rearview Mirror with
Compass and Temperature Display..............2-52
Outside Camper-Type Mirrors.........................2-56
Outside Power Mirrors...................................2-56
Outside Convex Mirror...................................2-57
Outside Heated Mirrors..................................2-58
Outside Automatic Dimming Mirror with Curb
View Assist..............................................2-58
OnStar
®System.............................................2-59
Section 2 Features and Controls
2-1

Resynchronization
Resynchronization may be necessary due to the
security method used by this system. The transmitter
does not send the same signal twice to the receiver. The
receiver will not respond to a signal that has been
sent previously. This prevents anyone from recording
and playing back the signal from the transmitter.
To resynchronize your transmitter, stand close to your
vehicle and press and hold the lock and unlock
buttons on the transmitter at the same time for
15 seconds. The door locks should cycle to conrm
synchronization. If the locks do not cycle, see your
dealer for service.
Doors and Locks
Door Locks
{CAUTION:
Unlocked doors can be dangerous.
Passengers — especially children — can
easily open the doors and fall out of a
moving vehicle. When a door is locked, the
handle will not open it. You increase the
chance of being thrown out of the vehicle
in a crash if the doors are not locked. So,
wear safety belts properly and lock the
doors whenever you drive.
Young children who get into unlocked
vehicles may be unable to get out. A child
can be overcome by extreme heat and can
suffer permanent injuries or even death
from heat stroke. Always lock your vehicle
whenever you leave it.
Outsiders can easily enter through an
unlocked door when you slow down or
stop your vehicle. Locking your doors can
help prevent this from happening.
2-8

Rear Door Security Locks
With this feature, you can lock the rear doors so they
can’t be opened from the inside by passengers.
This feature is located on
the inside edge of the rear
doors.
To use the locks, do the following:
1. Open one of the rear doors.
2. Move the lever forward to engage the rear door
security lock.
3. Close the door.
4. Do the same thing to the other rear door.The rear doors cannot be opened from the inside when
this feature is in use. If you want to open the rear
door while the security lock is engaged, unlock the door
and open the door from the outside. Move the lever
rearward to disengage the child security lock feature.
Lockout Protection
This feature protects you from locking your key in the
vehicle when the key is in the ignition and a door
is open.
If the power lock switch is pressed when a door is open
and the key is in the ignition, all of the doors will lock
and then the driver’s door will unlock.
2-13