1999 GMC YUKON ECU

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2-60
NOTICE:
Loading cargo that weighs more than 200 lbs.
(90.6 kg) on the luggage carrier may damage
your vehicle. When you carry large things, never
let them hang over the rear or the sides of your
vehicle. Load your cargo so that it rests on the
slats and does not scratch or damage the vehicle.
Put the cargo against the side rails and fasten it
securely to the luggage carrier.
Don't exceed the maximum vehicle capacity when
loading your vehicle. For more information on vehicle
capacity and loading, see ªLoading Your Vehicleº in
the Index.
To prevent damage or loss of cargo as you're driving,
check now and then to make sure the luggage carrier and
cargo are still securely fastened.
Be sure the cargo is properly loaded.
If small heavy objects are placed on the roof, place
the load in the area over the rear wheels. If you need
to, cut a piece of 3/8 inch plywood to fit inside the
crossrails and side rails to spread the load.

Tie the load to the crossrails or the side rail supports.
Use the crossrails only to keep the load from sliding.

If you need to carry long items, move the crossrails
as far apart as they will go. Tie the load to the
crossrails and tie loops. Also tie the load to the
bumpers. Do not tie the load so tightly that the
crossrails or side rails are damaged.

For the purpose of wind noise reduction, locate
the front crossrail approximately 18 to 24 inches
(46 cm to 58 cm) rearward of the front supports.

After moving the crossrails, be sure to tighten all the
slider screws.
Your vehicle has a Center High
-Mounted Stoplamp
(CHMSL) located above the tailgate glass or above the
rear load doors.
If items are loaded on the roof of the vehicle, care should
be taken not to block or damage the CHMSL unit.

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2-63
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.
Your visors have a strap to hold small items, such
as maps.
The visors have an extender on the inside edge. When
the visor is down, pull the extender out for extra glare
coverage at the front or side.
The visors also have mirrors with lights. The lights will
come on when you lift the mirror cover.
Universal Transmitter
This transmitter allows you to consolidate the functions
of up to three individual hand
-held transmitters. It will
operate garage doors and gates, or with the accessory
package, other devices controlled by radio frequency
such as home/office lighting and security systems.

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2-66 Training a Garage Door Opener with a
ªRolling Codeº Feature
If you programmed the universal transmitter, but the
garage door will not open, and if your garage door
opener was manufactured after 1995, your garage door
may have a security feature that changes the ªcodeº of
your garage door opener every time it is opened
or closed.
To determine if your garage door opener has this
ªrolling codeº feature, press the appropriate button on
the universal transmitter that was programmed. If the
red light flashes rapidly for one to two seconds, then
turns solid, your garage door opener has this feature.
To program a garage door opener with the rolling code
feature, do the following:
1. Program your hand
-held transmitter to the universal
transmitter by following the steps provided under
ªProgramming the Transmitterº earlier in
this section.2. Remove the cover panel from the garage door
opener receiver. It is located near the garage door
opener motor.
3. Locate the training button on the garage door opener
receiver. The exact location and color will vary
among brands.
4. Press the training button on the garage door opener
receiver for one to two seconds.
5. Return to your vehicle and press the programmed
button on the universal transmitter until the red light
flashes rapidly (about two seconds).
6. Release the button, then press it again to confirm
that it was programmed to the garage door
opener receiver.
You may now use either the universal transmitter or the
hand-held transmitter to open your garage door. If you
still have difficulty in programming and require
assistance, please call 1
-800-355-3515.

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2-80 Security Light
This light will come on
briefly when you turn the
key to START.
The light will stay on until the engine starts. If the light
flashes, the Passlock

System has entered a tamper
mode. If the vehicle fails to start, see ªPasslockº in
the Index.
If the light comes on continuously while driving and
stays on, there may be a problem with the Passlock
System. Your vehicle will not be protected by Passlock,
and you should see your GM dealer.
Service Four-Wheel Drive Warning Light
Your vehicle is equipped with an Automatic
Four
-Wheel-Drive Transfer Case. It has a computer
which controls the four
-wheel-drive system.
This light should come on
briefly when you turn on the
ignition, as a check to show
you it is working.
If the SERVICE 4WD light comes on, there may be a
problem with the Automatic Four
-Wheel-Drive system
and service is required. Malfunctions can be indicated
by the system before any problem is apparent, which
may prevent serious damage to the vehicle. This system
is also designed to assist your service technician in
correctly diagnosing a malfunction.

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3-15
A disc that has been ejected but is still sitting in the
remote CD player will be pulled back into the player
after approximately 30 seconds. This protects the disc
and player from damage. The disc will not start playing.
To remove the disc, press the EJECT button and remove
the disc from the player.
All of the compact disc functions are controlled by the
radio buttons except for EJECT. When a disc is in the
player, a CD symbol will appear on the display. When a
disc is playing, the letters CD will appear next to the CD
symbol in the bottom left corner. The track number will
also be displayed.
If the disc comes back out and ERR appears on the
display, it could be that:

The disc is upside down.

It is dirty, scratched or wet.

There's too much moisture in the air. (Wait about an
hour and try again.)

You are driving on a very rough road.
Please contact your dealership if any error recurs or
cannot be corrected.PREV (1): Press this button to go back to the start of
the current track if more than eight seconds have played.
Press PREV again to go to the previous track on the
disc.
NEXT (3): Press this button to advance to the next track
on the disc.
REV (4): Press and hold this button to quickly reverse
within a track. As the CD reverses, elapsed time will be
displayed to help you find the correct passage.
FWD (6): Press and hold this button to quickly advance
within a track. As the CD advances, elapsed time will be
displayed to help you find the correct passage.
SEEK: Press the left arrow while playing a CD to go
back to the start of the current track. It will go back to
the current track if more than eight seconds have played.
Press the left arrow again to go to previous tracks. Press
the right arrow to go to the next higher track on the disc.
RANDOM: Press P.SCAN to enter the random play
mode. RANDOM will appear on the display. While in
this mode, the tracks on the discs will be played in
random order. If you press SEEK, PREV or NEXT
while in the random mode, the previous or next track
will be scanned randomly. Press P.SCAN again to turn
off RANDOM and return to normal operation.

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3-20
1. Write down any three or four-digit number from
000 to 1999 and keep it in a safe place separate from
the vehicle.
2. Turn the ignition to ACCESSORY or RUN.
3. Turn the radio off.
4. Press the 1 and 4 buttons together. Hold them down
until
--- shows on the display. Next you will use the
secret code number which you have written down.
5. Press MN and 000 will appear on the display.
6. Press MN again to make the last two digits agree
with your code.
7. Press HR to make the first one or two digits agree
with your code.
8. Press AM
-FM after you have confirmed that the
code matches the secret code you have written down.
The display will show REP to let you know that you
need to repeat Steps 5 through 7 to confirm your
secret code.
9. Press AM
-FM and this time the display will show
SEC to let you know that your radio is secure. The
LED indicator by the volume control will begin
flashing when the ignition is turned off.Unlocking the Theft
-Deterrent Feature After a
Power Loss
Enter your secret code as follows; pause no more than
15 seconds between steps:
1. Turn the ignition on. LOC will appear on the display.
2. Press MN and 000 will appear on the display.
3. Press MN again to make the last two digits agree
with your code.
4. Press HR to make the first one or two digits agree
with your code.
5. Press AM
-FM after you have confirmed that the
code matches the secret code you have written down.
The display will show SEC, indicating the radio is
now operable and secure.
If you enter the wrong code eight times, INOP will
appear on the display. You will have to wait an hour
with the ignition on before you can try again. When you
try again, you will only have three chances to enter the
correct code before INOP appears.
If you lose or forget your code, contact your dealer.

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3-21
Disabling the Theft-Deterrent Feature
Enter your secret code as follows; pause no more than
15 seconds between steps:
1. Turn the ignition to ACCESSORY or RUN.
2. Turn the radio off.
3. Press the 1 and 4 buttons together. Hold them down
until SEC shows on the display.
4. Press MN and 000 will appear on the display.
5. Press MN again to make the last two digits agree
with your code.
6. Press HR to make the first one or two digits agree
with your code.
7. Press AM
-FM after you have confirmed that the
code matches the secret code you have written down.
The display will show
---, indicating that the radio is
no longer secured.
If the code entered is incorrect, SEC will appear on the
display. The radio will remain secured until the correct
code is entered.
When battery power is removed and later applied to a
secured radio, the radio won't turn on and LOC will
appear on the display.To unlock a secured radio, see ªUnlocking the
Theft
-Deterrent Feature After a Power Lossº earlier in
this section.
Understanding Radio Reception
AM
The range for most AM stations is greater than for FM,
especially at night. The longer range, however, can
cause stations to interfere with each other. AM can pick
up noise from things like storms and power lines. Try
reducing the treble to reduce this noise if you ever get it.
FM Stereo
FM stereo will give you the best sound, but FM signals
will reach only about 10 to 40 miles (16 to 65 km). Tall
buildings or hills can interfere with FM signals, causing
the sound to come and go.
Tips About Your Audio System
Hearing damage from loud noise is almost undetectable
until it is too late. Your hearing can adapt to higher
volumes of sound. Sound that seems normal can be loud
and harmful to your hearing. Take precautions by
adjusting the volume control on your radio to a safe
sound level before your hearing adapts to it.

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4-15 Before You Go Off-Roading
There are some things to do before you go out. For
example, be sure to have all necessary maintenance and
service work done. Check to make sure all underbody
shields (if so equipped) are properly attached. Be sure
you read all the information about your
four
-wheel-drive vehicle in this manual. Is there enough
fuel? Is the spare tire fully inflated? Are the fluid levels
up where they should be? What are the local laws that
apply to off
-roading where you'll be driving? If you
don't know, you should check with law enforcement
people in the area. Will you be on someone's private
land? If so, be sure to get the necessary permission.
Loading Your Vehicle for Off-Road Driving
There are some important things to remember about
how to load your vehicle.

The heaviest things should be on the load floor and
forward of your rear axle. Put heavier items as far
forward as you can.

Be sure the load is secured properly, so driving on
the off
-road terrain doesn't toss things around.
CAUTION:

Cargo on the load floor piled higher than
the seatbacks can be thrown forward
during a sudden stop. You or your
passengers could be injured. Keep cargo
below the top of the seatbacks.

Unsecured cargo on the load floor can be
tossed about when driving over rough
terrain. You or your passengers can be
struck by flying objects. Secure the
cargo properly.

Heavy loads on the roof raise the vehicle's
center of gravity, making it more likely to
roll over. You can be seriously or fatally
injured if the vehicle rolls over. Put heavy
loads inside the cargo area, not on the roof.
Keep cargo in the cargo area as far forward
and low as possible.
You'll find other important information in this manual.
See ªVehicle Loading,º ªLuggage Carrierº and ªTiresº
in the Index.