2004 GMC SIERRA ECU

The passenger sensing system will turn off the right
front passenger's frontal air bag under certain
conditions. The driver's air bag is not part of the
passenger sensing system. In addition to the passenger
sensing system, your vehicle also has an air bag off
switch located on the instrument panel.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
in¯ate) 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.
Never put a child in a rear-facing child restraint in
the right front passenger seat unless the passenger air
bag status indicator shows off. Never put a rear-facing
child restraint in the right front passenger seat unless the
air bag is off. Passenger Air Bag Status Indicator ± United States
Passenger Air Bag
Status Indicator
-Canada
1-82

{CAUTION:
A child in a rear-facing child restraint can be
seriously injured or killed if the right front
passenger's air bag in¯ates. This is because the
back of the rear-facing child restraint would be
very close to the in¯ating air bag. Be sure the air
bag is off before using a rear-facing child
restraint in the right front seat position.
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 a rear
seat whenever possible, 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
·the air bag off switch is in the off position
·or if there is a critical problem with the air bag
system or the passenger sensing system
When the passenger's frontal air bag has been turned
off either by the passenger sensing system or by the air
bag off switch, the off indicator will light and stay lit to
remind you that the air bag is off.
1-83

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 (Regular and Extended Cab) on
page 1-64
orSecuring a Child Restraint Designed for
the LATCH System (Front) on page 1-51.
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, use the air bag off switch to
turn off the air bag or secure the child in the child
restraint in a rear seat position in the vehicle if one is
available and check with your dealer. See
Air Bag
Off Switch on page 1-76for more on this, including
important safety information.
The passenger sensing system is designed to enable
(may in¯ate) 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 Ð 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 or
the air bag off switch is in the off position. If this
happens and the switch is in the proper position, 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.
1-84

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
(Crew Cab)..............................................2-12
Lockout Protection........................................2-13
Rear Doors..................................................2-13
Tailgate.......................................................2-14
Windows........................................................2-16
Manual Windows..........................................2-16
Power Windows............................................2-17
Swing-Out Windows......................................2-18
Sun Visors...................................................2-18
Theft-Deterrent Systems..................................2-19
Content Theft-Deterrent.................................2-19
Passlock
ž....................................................2-21Starting and Operating Your Vehicle................2-21
New Vehicle Break-In....................................2-21
Ignition Positions..........................................2-22
Starting Your Engine.....................................2-23
Engine Coolant Heater..................................2-25
Automatic Transmission Operation...................2-26
Manual Transmission Operation......................2-30
Four-Wheel Drive..........................................2-35
Parking Brake..............................................2-48
Shifting Into Park (P).....................................2-49
Shifting Out of Park (P).................................2-51
Parking Your Vehicle.....................................2-52
Parking Over Things That Burn.......................2-52
Engine Exhaust............................................2-53
Running Your Engine While You Are Parked. . . .2-53
Mirrors...........................................................2-54
Manual Rearview Mirror.................................2-54
Automatic Dimming Rearview Mirror with
OnStar
ž, Compass and Temperature
Display....................................................2-55
Section 2 Features and Controls
2-1

To replace the battery in the keyless entry transmitter
do the following:
1. Insert a dime, or similar object, in the slot between
the covers of the transmitter housing near the key
ring hole. Remove the bottom by twisting the dime.
2. Remove and replace the battery with a three-volt
CR2032 or equivalent battery, positive (+) side up.
3. Align the covers and snap them together.
4. Resynchronize the transmitter.
5. Check the operation of the transmitter.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 con®rm
synchronization. If the locks do not cycle, see your
dealer for service.
2-7

The following instructions tell you how to change the
automatic door unlock mode. Choose one of the
four programming options listed above before entering
the program mode. To enter the program mode, do
the following:
1. Begin with the ignition off. Then pull the turn
signal/multifunction lever toward you and hold
it there while you perform the next step.
2. Turn the key to RUN and LOCK twice. Then, with
the key in LOCK, release the turn
signal/multifunction lever. Once you do this, the
doors will lock and unlock, the horn will chirp twice,
and a 30-second timer will begin. You are now
ready to program the automatic door unlock feature.
3. Press the door unlock switch once. You will hear
one, two, three, or four chimes. The number of
chimes tells you which unlock mode is currently
selected. Continue to press the door unlock switch
until the number of chimes that you hear matches the
number of the mode that you want. If you take longer
than 30 seconds, the locks will automatically lock and
unlock and the horn will chirp twice to indicate that
you have left the program mode. If this occurs, you
can repeat the procedure beginning with Step 1 to
re-enter the programming mode.
You can exit the program mode any time by turning the
ignition to RUN. The doors will automatically lock
and unlock and the horn will chirp twice to indicate thatyou are leaving the program mode. If the lock/unlock
switches are not pressed while in the programming
mode, the current automatic settings will not be
modi®ed.
See your dealer for more information.
Rear Door Security Locks
(Crew Cab)
With this feature, you can lock the rear side doors so
that they cannot be opened from the inside by
passengers.
2-12

This feature is located on the inside edge of the rear
doors.
1. To use one of the locks do the following:
2. Open one of the rear doors.
3. To engage the rear door security lock, move the
lever forward.
4. To disengage the lock, move the lever rearward.
5. Close the door.
6. Do the same thing to the other rear door.
The rear doors of your vehicle 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.
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.
Rear Doors
Your vehicle may be equipped with a rear access
door(s) that allows easier access to the rear area of the
extended cab.
To open a rear access
door from the outside, ®rst
open the front door.
Then, use the handle
located on the front edge
of the rear access door
to open it.
You must fully close a rear access door before you can
close the front door.
2-13

To open a rear access
door from the inside, the
front door must be opened
®rst. Then, use the
handle located on the
inside of the rear access
door to open it.
If your vehicle is a Crew Cab
ž, you can open your
doors from the inside or outside. Your vehicle may also
have a feature which prevents children from opening
the rear doors. See
Rear Door Security Locks
(Crew Cab) on page 2-12for more information.
Tailgate
You can open the tailgate by lifting up on its handle
while pulling the tailgate toward you.
To shut the tailgate, ®rmly push it upward until it
latches.
After you put the tailgate back up, pull it back towards
you to be sure it latches securely.
Tailgate Removal
The tailgate on your vehicle can be removed to allow for
different loading situations. Although the tailgate can
be removed without assistance, you may want someone
to assist you with the removal to avoid possible
damage to the vehicle.
2-14