GMC 2004 Yukon XL Owner's Manual page 112

This message 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 flash. If using the
remote keyless entry transmitter, the door
does not need to be open.
If the delayed locking feature is active, the alarm
will not be activated until all doors are closed
and the security light goes off.
3. Close all doors. The security light will stop flashing
and stay solid. The light should go off after
approximately 30 seconds. The alarm is not
armed until the security light goes off.
If a door is opened without the key or the remote
keyless entry transmitter, the alarm will go off. Your
vehicle's headlamps will flash and the horn will sound
for about two minutes, then will turn off to save the
battery power.
2-18
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 after the 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 the system
has been armed.
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 or by
placing the key in the ignition and turning it to START.