Alarm system and horn (Description): Description and operation

Description

General

The anti-theft system deters the theft of the vehicle with both active and passive systems. The active systems monitor the vehicle perimeter and, in some markets the vehicle interior, for intrusion. If the system detects intrusion, an alarm sounds. The passive systems include a vehicle immobiliser as well as protection against intrusion through super locking the doors. The vehicle is immobilised whenever the ignition key is removed from the ignition switch. Super locking prevents the interior door handles from opening the doors. In addition, there are many features and functions that enhance system operation.

It is possible to perform the various functions associated with the anti-theft system remotely. To accomplish this, the handset generates a radio frequency when the lock button or unlock button is depressed. This signal is transmitted to the Body Control Unit (BCU) via a receiver located in front of rear sunroof beneath the headlining. Precise alignment of the handset to the receiver is not necessary. The approximate operating range between the handset and the receiver is 10 metres (33 feet).

It is important to understand the configuration of the system on each particular vehicle. There are many different combinations of features with dedicated operating modes. System configuration for each vehicle can be determined using TestBook.

The anti-theft system is controlled centrally by the BCU, which is located below and behind the passenger glovebox. A serial communication link communicates between the Intelligent Driver Module (IDM) located within the fusebox, the BCU and the LED located in the instrument panel.

The state of the alarm is stored in the BCU. If the battery is disconnected while the alarm is armed, the alarm will be triggered when the battery is reconnected.

NOTE: Disconnecting the battery while the alarm is armed triggers the alarm. Always disarm the alarm system before disconnecting the battery.

The BCU also receives inputs from the following components: l Ignition key in sensor. l Ignition switch. l Fuel cut off switch. l Fuel flap release switch.

The BCU also interacts with the following components: l Starter relay. l Vehicle horns. l Direction indicators. l Fuel flap release actuator. l Courtesy lamps.