Vehicle Theft Security System - Operation

OPERATION

The Vehicle Theft Security System (VTSS) is divided into two basic subsystems: a standard equipment vehicle immobilizer system (also known as the Drive Authorization System/DAS) and an optional Vehicle Theft Alarm (VTA) (also known as the Anti-Theft Alarm/ATA system or EDW). Following are paragraphs that briefly describe the operation of each of these two subsystems.

VEHICLE IMMOBILIZER SYSTEM

The vehicle immobilizer system is designed to provide passive protection against unauthorized vehicle use by disabling the engine after about two seconds of running, whenever any method other than a valid transmitter key is used to start the vehicle. The immobilizer also controls an electronic shaft lock module on the steering column that locks the steering shaft from rotation unless a valid transmitter key is detected in the Electronic Ignition Switch (EIS) (also known as the Electronic Ignition Switch/Central GateWay/EIS/CGW or EZS). The immobilizer is considered a passive protection system because it is always active and does not require any customer intervention.

The EIS uses InfraRed (IR) communication to obtain confirmation that the transmitter key is a valid key for operating the vehicle. The microprocessor-based EIS uses electronic messages to communicate with other electronic modules in the vehicle over the Controller Area Network (CAN) data bus. Communication - Operation. Pre-programmed transmitter keys are provided with the vehicle from the factory. If the customer would like additional keys other than those provided with the vehicle, they may be purchased from any authorized dealer and must be activated by the dealer using a diagnostic scan tool in order for the system to recognize them as valid keys.

The EIS performs a self-test of the immobilizer system and the shaft lock module each time the ignition switch is turned to the 2 (ON) position, and will store fault information in the form of a Diagnostic Trouble Code (DTC) if a system malfunction is detected. The EIS will also send an electronic message to the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN or KOMBI) if a fault is detected, and the EMIC displays a textual message in the multi-function display of the cluster as appropriate.

The hard wired circuits between components related to the immobilizer may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds.

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the immobilizer system or the electronic controls or communication between other modules and devices that provide some features of the immobilizer system. The most reliable, efficient, and accurate means to diagnose the immobilizer system or the electronic controls and communication related to immobilizer operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

VEHICLE THEFT ALARM

The Roof Control Module (RCM) (also known as the Overhead Control Panel/OCP control unit or DBE) is used on this vehicle to control and integrate many of the functions and features included in the Vehicle Theft Alarm (VTA) (also known as the Anti-Theft Alarm/ATA system or EDW). In the VTA system, the RCM receives inputs indicating the status of the door cylinder lock switches, the ignition switch, the heated rear window grids (if equipped), the hood ajar switch and the Central Locking (CL) switch in the instrument panel switch pod (also known as the center console switch unit, Switch Bank Module/SBM, Upper Control Panel/UCP or OBF). In vehicles built with the optional motion detection and tow-away protection features the intrusion sensors, inclination sensor and the switches in the OCP to activate or deactivate these features also provide inputs to the RCM.

Some of these RCM inputs are direct, while others are electronic message inputs received over the Controller Area Network (CAN) data bus. The RCM processes the information from all of these inputs, internally then provides both direct and electronic message outputs to the appropriate components or modules to provide the programmed VTA features.

The hard wired circuits between components related to the VTA system may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds.

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the VTA system or the electronic controls or communication between modules and devices that provide some features of the VTA system. The most reliable, efficient, and accurate means to diagnose the VTA system or the electronic controls and communication related to VTA system operation requires the use of a diagnostic scan tool. See the Vehicle Theft Security System menu item on the scan tool and refer to the appropriate diagnostic information.

Following are paragraphs that briefly describe the operation of each of the VTA features. See the owner's manual in the vehicle glove box for more information on the features, use and operation of the VTA.

ARMING

Arming of the VTA occurs when the LOCK button on the transmitter key is depressed to lock the vehicle. For arming to occur, the doors and the hood must be closed and the ignition switch must be in the OFF position when the transmitter key LOCK button is depressed. Once the VTA begins the arming sequence, the indicator in the CL switch in the instrument panel switch pod will flash. The alarm will be triggered if the vehicle is locked with the transmitter key, then is unlocked from the inside.

DISARMING

Disarming of the VTA occurs when the UNLOCK button of the transmitter key is depressed to unlock the vehicle. Once the VTA is disarmed, the indicator in the CL switch in the instrument panel switch pod will stop flashing. Once the alarm has been activated, either depressing the transmitter key UNLOCK button or inserting a valid key into the ignition switch lock will deactivate the alarm. If the vehicle is unlocked using the transmitter key, it will automatically lock again if a door is not opened within about 40 seconds.

ALARM

The VTA alarm output varies by the version of the VTA with which the vehicle is equipped. In all cases, the alarm provides both visual and audible outputs. The visual output will always be a flashing ON and OFF of the exterior lamps. However, for vehicles not equipped with the optional battery-powered siren, the audible output will be a pulsing of the horn; while, for vehicles with the battery-powered siren, the audible output will be a cycling of the siren. The inputs that will trigger the alarm include the door cylinder lock switches and the hood ajar switch; or on vehicles so equipped, the intrusion sensor or the inclination sensor.

INTRUSION ALARM

On vehicles equipped with the optional intrusion alarm, when the VTA is armed, the interior motion sensors are activated after about 40 seconds. If a side or rear window is broken and someone reaches inside, or if anything within the vehicle moves, the alarm is triggered. The motion sensors are automatically deactivated when the VTA is disarmed.

If people or animals will remain in the locked vehicle, the motion detect feature of the intrusion alarm can be disabled by turning the ignition switch to the 1 (UNLOCK or ACCESSORY) position and depressing the Motion Sensor OFF switch button on the RCM. The indicator in the Motion Sensor OFF switch button will illuminate for about 5 seconds after the button is released. The interior motion sensors will remain inactive until the next time the vehicle is locked using the transmitter key LOCK button.

TOW-AWAY PROTECTION

On vehicles equipped with the optional intrusion alarm, when the VTA is armed, the inclination sensor integral to the front interior motion sensor is activated after about 20 seconds. If the inclination of the vehicle changes, the alarm is triggered. The inclination sensor is automatically deactivated when the VTA is disarmed.

If the vehicle is to be loaded or transported on another vehicle, the inclination sensor for the tow-away protection feature can be disabled by turning the ignition switch to the 1 (UNLOCK or ACCESSORY) position and depressing the Inclination Sensor OFF switch button on the RCM. The indicator in the Inclination Sensor OFF switch button will illuminate for about 5 seconds after the button is released. The inclination sensor will remain inactive until the next time the vehicle is locked using the transmitter key LOCK button.