Antitheft and Alarm Systems: Description and Operation
VEHICLE THEFT SECURITYDESCRIPTION
The Vehicle Theft Security System (VTSS) is an available factory-installed option on this vehicle. The VTSS is comprised of two primary subsystems: Vehicle Theft Alarm (VTA) and Sentry Key Immobilizer System (SKIS).
The VTA is an active system that provides visual and audible responses as deterrents to and warnings of unauthorized vehicle tampering. The SKIS is a passive system that effectively immobilizes the vehicle against unauthorized operation. Following are paragraphs which describe the various components that are included in each of these subsystems of the VTSS.
Except for the Sentry Key transponders, which rely upon Radio Frequency (RF) communication, hard wired circuitry connects the VTA and SKIS components to the electrical system of the vehicle. These hard wired circuits are integral to several wire harnesses, which are routed throughout the vehicle and retained by many different methods. These circuits may be connected to each other, to the vehicle electrical system and to the SKIS components through the use of a combination of soldered splices, splice block connectors, and many different types of wire harness terminal connectors and insulators. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.
VEHICLE THEFT ALARM
The VTA is available in two different configurations for this vehicle: One configuration is designed for vehicles manufactured for sale in North America; while, the other configuration is designed for vehicles manufactured for sale in markets outside of North America, also referred to as Rest-Of-World (ROW) or export. In addition, the VTA for export is available in two versions: base and premium. All vehicles equipped with VTA are also equipped with the Remote Keyless Entry (RKE) system and the Sentry Key Immobilizer System (SKIS), regardless of their market destination.
The North American and export base version of the VTA provides perimeter vehicle protection by monitoring the vehicle doors, the tailgate, the rear flip-up glass and, for vehicles built for certain markets where it is required equipment, the hood. If unauthorized vehicle use or tampering is detected, these systems respond by pulsing the horn and flashing certain exterior lamps.
The export premium version of the VTA is only available in vehicles manufactured for sale in certain markets where it is required equipment. The export premium version of the VTA provides the same perimeter protection features as the base version, but adds interior vehicle intrusion protection. The export premium VTA also replaces the pulsing horn feature of the base version with an alarm siren as the audible deterrent, while retaining the flashing exterior lamps visual deterrent.
The VTA includes the following major components, which are described in further detail.
- Body Control Module (3) - The Body Control Module (BCM) is located on the Junction Block (JB) behind the driver side end of the instrument panel.
- Combination Flasher - An electronic combination flasher is integral to the hazard switch located in the center of the instrument panel above the radio.
- Door Ajar Switches - A door ajar switch is integral to the latch of each door in the vehicle.
- Flip-Up Glass Ajar Switch - A flip-up glass ajar switch is integral to the rear flip-up glass latch, located on the top of the tailgate near the center.
- Hood Ajar Switch (2) - A hood ajar switch is located on the right inner fender side shield of Export vehicles built for sale in markets where it is required equipment.
- Horn Relay - The horn relay is located on the Junction Block (JB) behind the driver side end of the instrument panel.
- Intrusion Transceiver Module (5) - An Intrusion Transceiver Module (ITM) is located near the center of the headliner in the passenger compartment of Export vehicles built for sale in markets where it is required equipment.
- Security Indicator - A security indicator is integral to the ElectroMechanical Instrument Cluster (EMIC).
- Siren (1) - An alarm siren is located on the front of the right front wheel house panel in the engine compartment of Export vehicles built for sale in markets where it is required equipment.
- Tailgate Ajar Switch - A tailgate ajar switch is integral to the latch for the tailgate in the vehicle.
SENTRY KEY IMMOBILIZER SYSTEM
The Sentry Key Immobilizer System (SKIS) is available as a factory-installed option on this vehicle. Vehicles equipped with the Vehicle Theft Alarm (VTA) are also equipped with SKIS. The SKIS provides passive vehicle protection by preventing the engine from operating unless a valid electronically encoded key is detected in the ignition lock cylinder.
The SKIS includes the following major components, which are described in further detail elsewhere in this service information:
- Powertrain Control Module - The Powertrain Control Module (PCM) is located on the left inner fender shield in the engine compartment.
- Sentry Key Remote Entry Module (4) - The Sentry Key REmote Entry Module (SKREEM) is sometimes referred to as the Wireless Control Module (WCM). The SKREEM is located on the right side of the steering column near the ignition lock cylinder housing and an integral molded plastic antenna ring circles the ignition lock cylinder like a halo. The SKREEM and its antenna are concealed beneath the steering column shrouds.
- Sentry Key Transponder - The Sentry Key transponder is contained within the Remote Keyless Entry (RKE) transmitter on the ignition key.
- Security Indicator - A security indicator is integral to the ElectroMechanical Instrument Cluster (EMIC).
OPERATION
The Vehicle Theft Security System (VTSS) is divided into two basic subsystems: Vehicle Theft Alarm (VTA) and Sentry Key Immobilizer System (SKIS). Following are paragraphs that briefly describe the operation of each of these two subsystems.
VEHICLE THEFT ALARM
The Body Control Module (BCM) is used on this vehicle to control and integrate many of the electronic functions and features included in the Vehicle Theft Alarm (VTA). In the VTA system, the BCM receives inputs indicating the status of the door ajar switches, the ignition switch, the tailgate ajar switch, the flip-up glass ajar switch, the power lock switches and, in vehicles built for certain markets where it is required, the hood ajar switch.
The BCM will process the information from all of these inputs and send control outputs to energize or de-energize the combination flasher, the horn relay (except vehicles with the export premium version of the VTA), and the security indicator as appropriate. In addition, in vehicles built for certain markets where the export premium version of the VTA is required, the BCM also exchanges electronic messages with the Intrusion Transceiver Module (ITM) over the Programmable Communications Interface (PCI) data bus to provide the features found in this version of the VTA.
The hard wired circuits and components of the VTA may be diagnosed and tested using conventional diagnostic tools and procedures. However, conventional diagnostic methods may not prove conclusive in the diagnosis of the BCM, the EMIC, the ITM, the PCI data bus or the electronic message inputs used to provide the electronic features of the VTA. The most reliable, efficient, and accurate means to diagnose the BCM, the EMIC, the ITM, the PCI data bus, and the electronic message inputs for the VTA requires the use of a diagnostic scan tool. See the Vehicle Theft Security System menu item on the scan tool.
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 the features, use and operation of the VTA.
ENABLING
The BCM must have the VTA function electronically enabled in order for the VTA to perform as designed. The logic in the BCM keeps its VTA function dormant until it is enabled using a diagnostic scan tool. The VTA function of the BCM is enabled on vehicles equipped with the VTA option at the factory, but a service replacement BCM must be VTA-enabled by the dealer using a diagnostic scan tool.
PRE-ARMING
The VTA has a pre-arming sequence. Pre-arming is initiated when a door, the tailgate, or the flip-up glass is open when the vehicle is locked using a power door lock switch, or when the Remote Keyless Entry (RKE) transmitter Lock button is depressed. Pre-arming will not occur if the key is in the ignition switch or the headlamps are turned on with the driver side front door open. When the VTA is pre-armed, the arming sequence is delayed until all of the doors, the tailgate and the flip-up glass have been closed. The VTA will remain in Pre-Armed mode for up to sixteen seconds after all doors, the tailgate and the flip-up glass have been closed.
ARMING
Passive arming of the VTA occurs when the vehicle is exited with the key removed from the ignition switch, the headlamps are turned off, and the doors are locked while they are open using the power lock switch. Active arming occurs when the LOCK button on the RKE transmitter is depressed to lock the vehicle after all of the doors, the tailgate and the flip-up glass are closed. For active arming to occur, the doors, the tailgate and the flip-up glass must be closed and the ignition switch must be in the OFF position when the RKE transmitter LOCK button is depressed. The power lock switch will not function if the key is in the ignition switch or the headlamps are turned on with the driver side front door open.
Once the VTA begins the passive or active arming sequence, the security indicator in the instrument cluster will flash rapidly for about sixteen seconds. This indicates that VTA arming is in progress. If the ignition switch is turned to the ON position, if a door or the tailgate is unlocked and opened by any means, or the RKE PANIC button (if equipped) is depressed during the sixteen second arming process, the security indicator will stop flashing and the arming process will abort.
On vehicles equipped with the hood ajar switch, the VTA arming sequence will occur regardless of whether the hood is open or closed, but the underhood area will not be protected unless the hood is closed when the VTA arming sequence begins. Also, if the status of the hood ajar switch changes from open to closed during the sixteen second arming process, the security indicator will stop flashing and the VTA arming sequence will abort. Once the sixteen second arming process is successfully completed, the security indicator will flash at a slower rate, indicating that the VTA is armed.
DISARMING
For vehicles built for the North American market, passive disarming of the VTA occurs by turning the ignition switch to the ON position using a valid Sentry Key Immobilizer System (SKIS) key. Active disarming of the VTA for any market occurs when the vehicle is unlocked by depressing the UNLOCK button of the RKE transmitter. Once the alarm has been activated, either disarming method will also deactivate the alarm. Depressing the PANIC button (if equipped) on the RKE transmitter will not disarm the VTA.
POWER-UP MODE
When the armed VTA senses that the battery has been disconnected and reconnected, it enters its power-up mode. In the power-up mode the alarm system remains armed following a battery failure or disconnect. If the VTA was armed prior to a battery disconnect or failure, the technician or vehicle operator will have to actively or passively disarm the alarm system after the battery is reconnected. The power-up mode will also apply if the battery goes dead while the system is armed, and battery jump-starting is attempted. The VTA will be armed until the technician or vehicle operator has actively or passively disarmed the alarm system. If the VTA is in the disarmed mode prior to a battery disconnect or failure, it will remain disarmed after the battery is reconnected or replaced, or if jump-starting is attempted.
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; however, the time intervals of these outputs vary by the requirements of the market for which the vehicle is manufactured. In all cases, the visual output will be a flashing on and off of the exterior lamps. For vehicles equipped with the North American or the export base version of the VTA, the audible output will be a pulsing of the horn. For vehicles with the export premium version of the VTA, the audible output will be a cycling of the alarm siren. the owner's manual in the glove box for details of the alarm output requirements of the specific market for which the vehicle was manufactured. The inputs that will trigger the alarm include the door ajar switches, the tailgate ajar switch, the flip-up glass ajar switch, and in vehicles built for certain markets where they are required, the hood ajar switch and the Intrusion Transceiver Module (ITM).
TAMPER ALERT
The VTA tamper alert feature will pulse the horn (or the alarm siren for the export premium version of the VTA) three times upon VTA disarming, if the alarm was triggered and has since timed-out, or if the battery has been disconnected and reconnected. This feature alerts the vehicle operator that the VTA alarm was activated while the vehicle was unattended.
INTRUSION ALARM
The intrusion alarm is an exclusive feature of the export premium version of the VTA, which is only available in certain markets where it is required. When the VTA is armed, a motion sensor in the Intrusion Transceiver Module (ITM) monitors the interior of the vehicle for movement. If motion is detected, the ITM sends an electronic message to the BCM over the PCI data bus to invoke the visual alarm feature, and sends an electronic message to the alarm siren in the engine compartment over a dedicated serial bus to invoke the audible alarm feature. The motion detect feature of the ITM can be disabled by depressing the Lock button on the RKE transmitter three times within fifteen seconds during VTA arming, while the security indicator is still flashing rapidly. The VTA provides a single short siren "chirp" as an audible confirmation that the motion detect disable request has been received.
The ITM must be electronically enabled in order for the intrusion alarm to perform as designed. The logic in the ITM keeps its intrusion alarm function dormant until it is enabled using a diagnostic scan tool. The intrusion alarm function of the ITM is enabled on vehicles equipped with this option at the factory, but a service replacement ITM must be configured and enabled by the dealer using a diagnostic scan tool.
SENTRY KEY IMMOBILIZER SYSTEM
The Sentry Key Immobilizer System (SKIS) 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 Sentry Key is used to start the vehicle. The SKIS is considered a passive protection system because it is always active when the ignition system is energized and does not require any customer intervention. The SKIS uses Radio Frequency (RF) communication to obtain confirmation that the key in the ignition switch is a valid key for operating the vehicle. The microprocessor-based SKIS hardware and software also uses electronic messages to communicate with other electronic modules in the vehicle over the Programmable Communications Interface (PCI) data bus.
Pre-programmed Sentry Key transponders are provided with the vehicle from the factory. Each Sentry REmote Entry Module (SKREEM) will recognize a maximum of eight Sentry Keys. If the customer would like additional keys other than those provided with the vehicle, they may be purchased from any authorized dealer. These additional keys must be programmed to the SKREEM in the vehicle in order for the system to recognize them as valid keys. This can be done by the dealer using a diagnostic scan tool or, if Customer Learn programming is an available SKIS feature in the market where the vehicle was purchased, the customer can program the additional keys, as long as at least two valid Sentry Keys are already available.
The SKREEM performs a self-test of the SKIS each time the ignition switch is turned to the ON position, and will store fault information in the form of a Diagnostic Trouble Code (DTC) if a system malfunction is detected. The SKIS can be diagnosed, and any stored DTC can be retrieved using a diagnostic scan tool.