2001 GMC YUKON service

2-11
To replace the battery in the keyless entry transmitter:
1. Insert a dime 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 seven seconds. The door locks should cycle to
confirm synchronization. If the locks do not cycle,
see your dealer for service.

2-15 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 message 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.
If the alarm does not sound when it should but the
vehicle's headlamps flash, check to see if the horn
works. The horn fuse may be blown. To replace the fuse,
see ªFuses and Circuit Breakersº in the Index.
If the alarm does not sound or the vehicle's headlamps
do not flash, the vehicle should be serviced by an
authorized service center.
Passlock

Your vehicle is equipped with the Passlock
theft
-deterrent system.
Passlock is a passive theft
-deterrent system. Passlock
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, fuel is disabled.
If the engine stalls and the SECURITY message flashes,
wait until the light stops flashing before trying to restart
the engine. Remember to release the key from START
as soon as the engine starts.
If the engine is running and the SECURITY message
comes on, you will be able to restart the engine if you turn
the engine off. However, your Passlock system is not
working properly and must be serviced by your dealer.
Your vehicle is not protected by Passlock at this time. You
may also want to check the fuse (see ªFuses and Circuit
Breakersº in the Index). See your dealer for service.
In an emergency, call the GM Roadside Assistance
Center. See ªRoadside Assistanceº in the Index.

2-17
NOTICE:
If your key seems stuck in LOCK and you can't
turn it, be sure you are using the correct key; if
so, is it all the way in? Turn the key only with
your hand. Using a tool to force it could break
the key or the ignition switch. If none of this
works, then your vehicle needs service.
OFF (C): This position lets you turn off the engine.
Use OFF if you must have your vehicle in motion while
the engine is off (for example, if your vehicle is
being pushed).
RUN (D): This is the position for driving.
START (E): This position starts your engine.
Retained Accessory Power (RAP)
(If Equipped)
Your vehicle may be equipped with a Retained
Accessory Power (RAP) feature which will allow
certain features on your vehicle to continue to work up
to 20 minutes after the ignition key is turned to OFF.Your radio, power windows, sunroof (if equipped), and
OnStar

System (if equipped) will work when the
ignition key is in RUN or ACCESSORY. Once the key
is turned from RUN to OFF, these features will continue
to work for up to 20 minutes or until a door is opened.
Starting Your Engine
Move your shift lever to PARK (P) or NEUTRAL (N).
Your engine won't start in any other position
-- that's a
safety feature. To restart when you're already moving,
use NEUTRAL (N) only.
NOTICE:
Don't try to shift to PARK (P) if your vehicle is
moving. If you do, you could damage the
transmission. Shift to PARK (P) only when your
vehicle is stopped.
1. With your foot off the accelerator pedal, turn the
ignition key to START. When the engine starts, let
go of the key. The idle speed will go down as your
engine gets warm.

2-26
4HI: Use 4HI when you need extra traction, such as on
snowy or icy roads or in most off
-road situations. This
setting also engages your front axle to help drive your
vehicle. This is the best setting to use when plowing snow.
4LO: This setting also engages your front axle and
delivers extra torque. You may never need 4LO. It sends
maximum power to all four wheels. You might choose
4LO if you are driving off
-road in deep sand, deep mud,
deep snow and climbing or descending steep hills.
CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the transmission
is in PARK (P). You or someone else could be
seriously injured. Be sure to set the parking
brake before placing the transfer case in
NEUTRAL. See ªParking Brakeº in the Index.
NEUTRAL: Shift the vehicle's transfer case to
NEUTRAL only when towing your vehicle. See
ªRecreational Vehicle Towingº or ªTowing Your
Vehicleº in the Index for more information.Indicator lights in the switches show which setting you
are in. The indicator lights will come on briefly when
you turn on the ignition and one will stay on. If the
lights do not come on, you should take your vehicle to
your dealer for service. An indicator light will flash
while shifting the transfer case. It will remain
illuminated when the shift is complete. If for some
reason the transfer case cannot make a requested shift, it
will return to the last chosen setting.
If the SERVICE 4WD light stays on, you should take
your vehicle to your dealer for service. See ªService
4WDº in the Index for further information.
Shifting to 4HI or AUTO 4WD
Press and release the 4HI or AUTO 4WD switch. This
can be done at any speed (except when shifting from
4LO), and the indicator light will flash while shifting.
It will remain illuminated when the shift is completed.
Shifting to 2HI
Press and release the 2HI switch. This can be done at
any speed (except when shifting from 4LO).

2-46 Fog Lamps (If Equipped)
If you have fog lamps, use them for better vision in foggy
or misty conditions. Your parking lamps and/or low
-beam
headlamps must be on for your fog lamps to work.
The fog lamp button is
located on the left side of
the instrument panel.
Press the button to turn the fog lamps on. Press the
button again to turn them off. An indicator light will
glow in the button when the fog lamps are on.
Remember, fog lamps alone will not give off as much
light as your headlamps. Never use your fog lamps in
the dark without turning on your headlamps.
The fog lamps will go off whenever your high
-beam
headlamps come on. When the high beams go off,
the fog lamps will come on again.The fog lamps will be cancelled after the ignition is
turned off. If you still want to use the fog lamps after
you restart the vehicle, you will need to press the fog
lamp button again.
Auxiliary Roof Mounted Lamp Switch
(If Equipped)
This switch includes wiring
provisions for a dealer or a
qualified service center to
install an auxiliary roof
lamp. This switch is
located on the center of
the instrument panel near
the comfort controls.
When the switch wiring is connected to an auxiliary roof
mounted lamp, pressing the button will activate the lamp
and illuminate an indicator light near the button. Pressing
the button again will turn off the roof mounted lamp.
If your vehicle has this switch, your vehicle may have
the Snow Plow Prep Package. For further information
see ªSnow Plow Prep Packageº in the Index.

2-61
Changes and modifications to this system by other than
an authorized service facility could void authorization to
use this equipment.
Programming the Transmitter
Do not use the HomeLink
Transmitter with any garage
door opener that does not have the ªstop and reverseº
feature. This includes any garage door opener model
manufactured before April 1, 1982.
Be sure that people and objects are clear of the garage
door you are programming.
Your vehicle's engine should be turned off while
programming the transmitter. Follow these steps to
program up to three channels:
1. If you have previously programmed a transmitter
channel, proceed to Step 2. Otherwise, hold down
the two outside buttons on the HomeLink
Transmitter until the indicator light begins to flash
rapidly (after 20 seconds). Then release the buttons.
This procedure initializes the memory and erases any
previous settings for all three channels.
2. Decide which one of the three channels you want to
program. Hold the end of the hand
-held transmitter
about 2 to 5 inches (5 to 13 cm) away from the
surface of the HomeLink Transmitter so that you
can still see the indicator light.3. Using both hands, press the hand
-held transmitter
button and the desired button on the HomeLink
Transmitter. Continue to press both buttons
through Step 4.
4. Hold down both buttons until you see the light on
the HomeLink Transmitter flash rapidly. The rapid
flashing indicates that the HomeLink Transmitter has
been programmed. Release both buttons once the
light starts to flash rapidly.
If you have trouble programming the HomeLink
Transmitter, make sure that you have followed the
directions exactly as described and that the battery in the
hand
-held transmitter is not dead. If you still cannot
program it, turn the hand
-held transmitter end over end
and try again. The HomeLink Transmitter may not work
with older garage door openers that do not meet current
Federal Consumer Safety Standards. If you cannot
program the transmitter after repeated attempts, refer to
ªTraining a Garage Door Opener with Rolling Codesº
later in this section or contact the manufacturer of the
unit at 1
-800-355-3515.
Be sure to keep the original hand
-held transmitter
in case you need to erase and reprogram the
HomeLink Transmitter.

2-63
3. Return to the HomeLink Transmitter in your vehicle
and firmly press and release the HomeLink Transmitter
button you have already programmed for two to three
seconds. Press and release the button again (you may
need to do this step up to three times) to make sure
that the HomeLink Transmitter has been trained to the
garage door opener motor head unit. Check that the
training was successful. The motor head unit indicator
light should no longer be flashing.
The garage door opener should now recognize the
HomeLink Transmitter. You may either use the
HomeLink Transmitter or the hand
-held transmitter to
open the garage door.
If after following these instructions, you still have
problems training the garage door opener, call the
manufacturer of the unit at 1
-800-355-3515.
Erasing Channels
To erase all three programmed channels, hold down the
two outside buttons until the indicator light begins to
flash (after 20 seconds). Release both buttons.
Accessories
Accessories for the HomeLink
Transmitter are
available from the manufacturer of the unit.
If you would like additional information, please
call 1
-800-355-3515.
OnStar
System (If Equipped)
OnStar is a vehicle communications system that
offers a variety of services and provides a hands
-free
communication link between you and the OnStar Center.
A service subscription agreement and fee are required in
order to receive OnStar service. Services are available
24 hours a day, 7 days a week. For more information,
call 1
-888-ONSTAR-7 (1-888-667-8277).
OnStar Services Button: Press this button once
to contact an advisor who will be able to assist you with
these services. If you are not quickly connected, the
system will automatically reset and redial. This ensures
connection to the center; there is no additional action
required. Press the Call Answer/End button to cancel the
automatic redial.
Emergency Button: In an emergency situation,
press the emergency service button. Upon receiving the
call, an advisor at the center will locate your vehicle and
assess the situation. If necessary, the advisor will alert
the nearest emergency service provider.

2-64
Call ANSWER/END Button: Use this button
to answer a call. (If you are receiving a call, the audio
system will mute, and the ring will be heard). Press this
button at the end of a call to disconnect and return the
audio system to its previous settings. This button will
also cancel a call if one of the buttons is accidentally
pressed or if the automatic redial function is activated.
Volume Control: You can control the volume of the
OnStar System using either the volume control knob on
the radio or using the steering wheel controls, if equipped.
Telltale Light: This light will indicate the status of
the system. A solid green light will come on when you
start the vehicle to let you know that the system is on
and is ready to make or receive calls.
If the light blinks green it means that an incoming
or outgoing call is in progress. Press the Call
ANSWER/END button if you notice the light blinking
and you are not on a call.
The light will be red in the event of an OnStar system
malfunction. If this occurs press the OnStar button to
attempt to contact an advisor. If the connection is made,
the advisor will assist you with steps to take to make
sure that the system is functioning properly. If you
cannot contact the advisor, take your vehicle to your
dealership as soon as possible for assistance.
Safety and Security Services

Automatic Notification of Air Bag
Deployment
-- If an air bag deploys, a priority
emergency signal is sent automatically to the center.
An advisor will locate your vehicle's position, try to
contact you and assist you in the situation. If the
center is unable to contact you, an emergency service
provider will be contacted.

Stolen Vehicle Tracking
-- Call the center at
1
-888-4-ONSTAR (1-888-466-7827) to report your
vehicle stolen. The system can then locate and track
your vehicle and the advisor will be able to notify
the proper authorities.

Roadside Assistance with Location
-- For vehicle
breakdowns, press the OnStar button. An advisor
will contact the appropriate help.

Remote Diagnostics
-- If an instrument panel light
comes on, the center can perform a check of the
engine on
-board computer. An advisor can then
recommend what action needs to be taken.

OnStar MED
-NET -- Med-Net can store your
personal medical history and provide it to emergency
personnel if necessary.

Accident Assist
-- An advisor can provide
step
-by-step guidance following an accident.