GMC Yukon 2021 Owner's Manual page 27

26 Keys, Doors, and Windows
key a second time will bypass the
30-second delay and immediately arm
the alarm system.
The vehicle alarm system will not arm if the
doors are locked with the mechanical key.
If the driver door is opened without first
unlocking with the remote key, the horn will
chirp and the lights will flash to indicate
pre-alarm. If the vehicle is not started,
or the door is not unlocked by pressing
on the remote key during the 10-second
pre-alarm, the alarm will be activated.
The alarm will also be activated if a
passenger door, the liftgate, or the hood is
opened without first disarming the system.
When the alarm is activated, the turn
signals flash and the horn sounds for about
30 seconds. The alarm system will then
re-arm to monitor for the next unauthorized
event.
Disarming the Alarm System
To disarm the alarm system or turn off the
alarm if it has been activated:
Press on the remote key.
Unlock the vehicle using the Keyless
Access system.
Start the vehicle.
To avoid setting off the alarm by accident:
Lock the vehicle after all occupants have
exited.
Always unlock a door with the remote
key, or use the Keyless Access system.
Unlocking the driver door with the
mechanical key will not disarm the
system or turn off the alarm.
How to Detect a Tamper Condition
If is pressed on the remote key and the
horn chirps three times, an alarm occurred
previously while the alarm system was
armed.
If the alarm has been activated, a message
will appear on the DIC.
Power Sounder, Inclination Sensor, and
Intrusion Sensor
In addition to the standard theft-deterrent
system features, this system may also have
a power sounder, inclination sensor, and
intrusion sensor.
The power sounder provides an audible
alarm which is distinct from the vehicle s
horn. It has its own power source, and can
sound an alarm if the vehicle s battery is
compromised.
The inclination sensor can set off the alarm
if it senses movement of the vehicle, such
as a change in vehicle orientation.
The intrusion sensor monitors the vehicle
interior, and can activate the alarm if it
senses unauthorized entry into the vehicle s
interior. Do not allow passengers or pets to
remain in the vehicle when the intrusion
sensor is activated.
Before arming the theft-deterrent system
and activating the intrusion sensor:
Make sure all doors and windows are
completely closed.
Secure any loose items such as a
sunshades.
Make sure there are no obstructions
blocking the sensors in the front overhead
console.
Close DVD screens before leaving the
vehicle.