2004 GMC YUKON DENALI ECU

Your vehicle has a rear seat that will accommodate a
rear-facing child restraint. A label on your sun visor says,
ªNever put a rear-facing child seat in the front.º This
is because the risk to the rear-facing child is so great, if
the air bag deploys.
{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.
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.
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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 1-68.
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 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. 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.
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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.............................................2-9
Programmable Automatic Door Locks..............2-10
Rear Door Security Locks..............................2-12
Lockout Protection........................................2-13
Liftgate/Liftglass............................................2-13
Windows........................................................2-14
Power Windows............................................2-15
Sun Visors...................................................2-16
Theft-Deterrent Systems..................................2-16
Content Theft-Deterrent.................................2-16
Passlock
ž....................................................2-18
Starting and Operating Your Vehicle................2-18
New Vehicle Break-In....................................2-18
Ignition Positions..........................................2-19Starting Your Engine.....................................2-19
Adjustable Throttle and Brake Pedal................2-21
Engine Coolant Heater..................................2-21
Automatic Transmission Operation...................2-22
All-Wheel Drive............................................2-25
Parking Brake..............................................2-26
Shifting Into Park (P).....................................2-27
Shifting Out of Park (P).................................2-29
Parking Over Things That Burn.......................2-30
Engine Exhaust............................................2-30
Running Your Engine While You Are Parked. . . .2-31
Mirrors...........................................................2-32
Automatic Dimming Rearview Mirror
with OnStar
ž, Compass and
Temperature Display..................................2-32
Outside Power Mirrors...................................2-35
Outside Convex Mirror...................................2-36
Outside Heated Mirrors..................................2-36
Outside Automatic Dimming Mirror with
Curb View Assist.......................................2-37
Section 2 Features and Controls
2-1

To replace the battery in the keyless entry transmitter,
do the following:
1. Insert a thin object, such as a coin, in the slot
between the covers of the transmitter housing
near the key ring hole. Remove the bottom
by twisting the coin.
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. See
ªResynchronizationº next.
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

Rear Door Security Locks
If your vehicle is equipped with this feature, you can
lock the rear side doors so they cannot be opened from
the inside by passengers.
This feature is located on
the inside edge of the
rear doors.To use one of the locks do the following:
1. Open one of the rear doors.
2. To engage the rear door security locks, move the
lever forward.
3. To disengage the lock, move the lever rearward.
4. Close the door.
5. 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.
2-12

Sun Visors
To block out glare, you can swing down the visors.
You can also swing them out to help block glare at the
front and side windows.
Illuminated Visor Vanity Mirrors
Pull the sunvisor down and lift the mirror cover to turn
on the lamps.
Theft-Deterrent Systems
Vehicle theft is big business, especially in some cities.
Although your vehicle has a number of theft-deterrent
features, we know that nothing we put on it can make it
impossible to steal.
Content Theft-Deterrent
Your vehicle is equipped with a content theft-deterrent
alarm system.
With this system, the
security light in the
instrument panel cluster will
¯ash as you open the door
if your ignition is off.
This light reminds you to activate the theft-deterrent
system. Here's how to do it:
1. Open the door.
2. Lock the door with the power door lock switch or
the remote keyless entry transmitter. The security
light should come on and stay on.
3. Close all doors. The security light should go off
after about 30 seconds. The alarm is not armed
until the security light goes off.
If a locked door is opened without the key or the remote
keyless entry transmitter, the alarm will go off. The
headlamps and parking lamps will ¯ash for two minutes,
and the horn will sound for 30 seconds, then will turn
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off to save the battery power. You can choose different
feedback options for the alarm. SeeDriver Information
Center (DIC) on page 3-46.
Remember, the theft-deterrent system won't activate if
you lock the doors with a key or use the manual
door lock. It activates only if you use a power door lock
switch with the door open, or with the remote keyless
entry transmitter. You should also remember that
you can start your vehicle with the correct ignition key if
the alarm has been set off.
Here's how to avoid setting off the alarm by accident:
·If you don't want to activate the theft-deterrent
system, the vehicle should be locked with the door
key
afterthe doors are closed.
·Always unlock a door with a key, or use the remote
keyless entry transmitter. Unlocking a door any
other way will set off the alarm.
If you set off the alarm by accident, unlock any door with
the key. You can also turn off the alarm by pressing
unlock on the remote keyless entry transmitter. The alarm
won't stop if you try to unlock a door any other way.
Testing the Alarm
The alarm can be tested by following these steps:
1. From inside the vehicle, lower the driver's window
and open the driver's door.
2. Activate the system by locking the doors with the
power door lock switch while the door is open, or
with the remote keyless entry transmitter.
3. Get out of the vehicle, close the door and wait for
the security light to go out.
4. Then reach in through the window, unlock the door
with the manual door lock and open the door. This
should set off the alarm.
While the alarm is set, the power door unlock switch is
not operational.
If the alarm does not sound when it should but the
headlamps ¯ash, check to see if the horn works. The
horn fuse may be blown. To replace the fuse, see
Fuses
and Circuit Breakers on page 5-103.
If the alarm does not sound or the headlamps do not
¯ash, the vehicle should be serviced by your dealer.
2-17

Passlockž
Your vehicle is equipped with the Passlockž
theft-deterrent system.
Passlockžis a passive theft-deterrent system. Passlockž
enables fuel if the ignition lock cylinder is turned with
a valid key. If a correct key is not used or the ignition
lock cylinder is tampered with, the fuel system is
disabled and the vehicle will not start.
During normal operation, the security light will turn off
approximately ®ve seconds after the key is turned
to RUN.
If the engine stalls and the security light ¯ashes, wait
about 10 minutes until the light stops ¯ashing before
trying to restart the engine. Remember to release
the key from START as soon as the engine starts.
If the engine does not start after three tries, the vehicle
needs service.
If the engine is running and the security light comes on,
you will be able to restart the engine if you turn the
engine off. However, your Passlock
žsystem is
not working properly and must be serviced by your
dealer. Your vehicle is not protected by Passlock
žat this
time. You may also want to check the fuse. See
Fuses and Circuit Breakers on page 5-103. See your
dealer for service.
In an emergency, call the Roadside Assistance Center.
See
Roadside Assistance Program on page 7-5.
Starting and Operating Your
Vehicle
New Vehicle Break-In
Notice:Your vehicle does not need an elaborate
ªbreak-in.º But it will perform better in the long run
if you follow these guidelines:
·Keep your speed at 55 mph (88 km/h) or less for
the ®rst 500 miles (805 km).
·Do not drive at any one speed Ð fast or
slow Ð for the ®rst 500 miles (805 km). Do not
make full-throttle starts.
·Avoid making hard stops for the ®rst 200 miles
(322 km) or so. During this time your new
brake linings are not yet broken in. Hard stops
with new linings can mean premature wear
and earlier replacement. Follow this breaking-in
guideline every time you get new brake
linings.
·Do not tow a trailer during break-in. SeeTowing
a Trailer on page 4-51
for more information.
2-18