The alarm system offers volumetric and perimeter protection against intrusion into the vehicle.A special control unit (integrated in the body computer) checks:
the state of the doors and lids, via switches in the handles (perimeter control)
the presence of a moving object inside the passenger compartment, by means of volumetric sensor (volumetric control)
an attempt to lift the vehicle or steal part of it (e.g. the wheels) through a tilt sensor
the condition of the system supply leads
the operation of the keyless-go knob
The control unit is equipped with an autodiagnostic function which detects and memorizes faults and problems in the actual control and the system components; in addition, it checks the condition of the connecting cables and memorizes the number of activations and times the alarm has been operated.The control unit operating logic can be modified in order to satisfy the legal requirements which govern the use of alarm systems in the various markets.The alarm siren is located at the front, under a liner on the left of the engine compartment. The vehicle is equipped with a recognition device for the system with passive entry: in this case the recognition of the transponder (CID) is requested at the passive entry control unit.This standard procedure is repeated each time the body computer has to ask the passive entry control unit for actions checking whether or not there is one or more enabled CIDs (equivalent to the reading of a transponder key) (near the vehicle or in the passenger compartment).The volumetric sensors check that there are no intrustions in the vehicle.They are located in the roof control unit: they consist of a transmitter and a receiver. A variation in the volume identified by the waves inside the passenger compartment produces an alarm situation which is immediately signalled to the Body Computer control unit.The tilt sensor checks the position along the two axes, starts the check on the angular position of the vehicle which ends after 30 secs and is designed to produce a reference position. The alarm should be produced before an angle of 3° in relation to the initial position is reached. The roof control unit sends the (volumetric) EXCLUS and (tilt) EXCLAINC message to the body computer via the A-BUS.During the rest state, with the alarm system switched off and the ignition switched off, the volumetric and tilt protection systems can be manually excluded using special buttons so that the relevant sensors are not engaged.all Passive Entry versions