Operation CHARM: Car repair manuals for everyone.

Principles of Operation (How Does It Work?)

Perimeter Alarm Protection Feature
The following events occur when the perimeter alarm system is armed:
^ If the doors are locked with the keyless entry keypad or a keyless entry remote transmitters the Driver Door Module (DDM) communicates with the Lighting Control Module (LCM) through the SCP network to arm the perimeter alarm and interior scanning intrusion sensor system.
^ If the doors are locked with the driver door lock cylinder switch (inputs to the LCM), the LCM arms the perimeter alarm, but does not arm the intrusion sensing system. The LCM then transmits a SCP message to the DDM to lock all doors (referred to as central locking).
^ If the doors are locked using the driver or passenger power door lock switch, the DDM communicates with the LCM through the SCP network requesting perimeter alarm activation once all doors are closed.
^ 20 seconds after the last door is closed the arming sequence will be complete.
^ If a door, the hood, or luggage compartment lid is opened during the 20 second pre-arming period entry will not be armed. Once the door hood or luggage compartment lid is closed, the associated timer is reset and a new 20 second time-out will occur. Each closure (or entry point) has its own independent timer.
^ The interior scanning system is not armed until all doors and the luggage compartment are closed.

When armed, opening the doors, opening the hood, interior movement (if the intrusion sensor is armed), or turning the ignition switch from OFF to RUN with an unprogrammed key will activate the alarm.

Arming of the system can be cancelled by:
^ unlocking a door using one of the front door unlock switches before 20 seconds have elapsed since the lock command was received.
^ using the keyless entry keypad code.
^ using a keyless entry remote transmitter.
^ unlocking the driver door with a key.
^ turning the ignition switch to RUN with a valid programmed key.

The luggage compartment key cylinder will not disarm the perimeter alarm (driver, passenger doors or hood). The luggage compartment alarm and interior scanning system can be temporarily inhibited by using the keyless entry remote transmitter luggage compartment release button or keyless entry keypad to open the luggage compartment or luggage compartment key cylinder to open the luggage compartment. Once the luggage compartment closes, the perimeter alarm systems will immediately start monitoring the luggage compartment and the interior scanning system will be armed.

The alarm system will activate if any of the doors, the hood, or the luggage compartment are opened, or air movement is detected in the interior of the vehicle.

Any of the following procedures will disarm a triggered system:
^ unlocking the driver door with the key.
^ unlocking the driver door using the keyless entry keypad code.
^ unlocking the driver door by pressing the UNLOCK button of the keyless entry remote transmitter.
^ turning the ignition switch to RUN with a valid programmed key.

Panic Alarm
The personal security alarm is operated from the keyless entry remote transmitter. Pressing the button marked PANIC on the keyless entry remote transmitter will cause the horns to sound and the high beam headlamps, parking lamps and courtesy lamps to flash for 2.75 minutes. The panic alarm can be activated when the perimeter alarm system is armed or disarmed with the ignition in the OFF position. The system is only disabled when the ignition switch is in the RUN, ACC or START positions. Deactivating a triggered personal security alarm is done by pressing the PANIC button again.