SIREN
DESCRIPTION
An alarm siren module is part of the premium version of the Vehicle Theft Alarm (VTA) in the Vehicle Theft Security System (VTSS). The premium version of the VTA is only available in vehicles built for certain markets, where the additional features offered by this system are required. This unit is designed to provide the audible alert requirements for the premium VTA.
The alarm siren module consists of microprocessor-based electronic control circuitry, the siren, and a nickel metal hydride backup battery. All of the alarm module components are protected and sealed within a molded plastic housing. An integral connector receptacle (3) extends from the housing and connects the unit to the vehicle electrical system through a dedicated take out and connector of the engine compartment wire harness. The housing also has a threaded insert within a mounting hole through which a screw (2) secures it to a bell shaped stamped metal mounting bracket (1). The siren and bracket unit are located on the outboard side of the right front fender load path beam where it is concealed by the right front fender above the wheel house splash shield. Two screws and U-nuts secure the mounting bracket to the vehicle.
The alarm siren module cannot be repaired or adjusted and, if ineffective or damaged, it must be replaced.
OPERATION
The microprocessor within the alarm siren module provides the siren unit features and functions based upon internal programming and electronic arm and disarm messages received from the Intrusion Transceiver Module (ITM) over a dedicated serial bus communication circuit. The siren module receives battery voltage on a fused B(+) circuit through a fuse in the Totally Integrated Power Module (TIPM), and receives a path to ground through a ground circuit in the engine compartment wire harness. These connections allow the siren to remain operational, regardless of the ignition switch position.
When the premium version of the Vehicle Theft Alarm (VTA) is armed, the siren module continuously monitors electronic message inputs from the ITM to sound its internal siren. While armed, the siren also enters its auto-detect mode. While in the auto-detect mode, if the siren module detects that its power supply or communication circuits are being tampered with or have been sabotaged, it will sound an audible alarm and continue to operate through an on-board backup battery. If the siren module is in its disarmed mode when its power supply or communication circuits are interrupted, the siren will not sound.
The state of charge of the siren module backup battery is automatically maintained. The battery is trickle charged approximately 2 minutes during every hour of operation through the battery voltage and ground circuits to the siren module.
The siren will self-detect problems with its internal and external power supply and communication circuits, then send electronic messages indicating the problem to the ITM upon receiving an arm or disarm request message. The ITM will store a Diagnostic Trouble Code (DTC) for any detected alarm siren module fault. The DTC can then be retrieved with a diagnostic scan tool through the 16-way Data Link Connector (DLC) located under the driver side lower edge of the instrument panel over the Controller Area Network (CAN) data bus.
The hard wired inputs and outputs for the alarm siren module may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the alarm siren module or the electronic controls or communication between other modules and devices that provide some features of the VTA system. The most reliable, efficient, and accurate means to diagnose the alarm siren module or the electronic controls and communication related to alarm siren module operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.
REMOVAL
1. Disconnect and isolate the battery negative cable.
2. Remove the splash shield from the right front wheel house. (Refer to 23 - BODY/EXTERIOR/SPLASH SHIELD - FRONT WHEELHOUSE - REMOVAL).
3. Locate the alarm siren module (1) on the outboard side of the right front fender load path beam (4).
4. Disconnect the engine compartment wire harness connector (5) from the connector receptacle near the back of the siren.
5. Remove the two screws (2) that secure the siren mounting bracket to the load path beam.
6. Remove the siren and mounting bracket from the load path beam as a unit.
INSTALLATION
1. Check to be certain that the two U-nuts (3) are in good condition and properly installed in the outboard side of the right front fender load path beam.
2. Position the alarm siren module (1) to the load path beam as a unit.
3. Install and tighten the two screws (2) that secure the siren mounting bracket to the two U-nuts in the load path beam. Tighten the screws to 5 N·m (40 in. lbs.).
4. Reconnect the engine compartment wire harness connector (5) to the connector receptacle near the back of the siren.
5. Reinstall the splash shield into the right front wheel house. (Refer to 23 - BODY/EXTERIOR/SPLASH SHIELDS - FRONT WHEELHOUSE - INSTALLATION).
6. Reconnect the battery negative cable.
NOTE: If the alarm siren module has been replaced with a new unit, a diagnostic scan tool MUST be used to initialize and configure the new unit in the Intrusion Transceiver Module (ITM) before the Vehicle Theft Security System (VTSS) can operate as designed. Follow the programming steps outlined in the diagnostic scan tool for INITIALIZE SIREN under MISCELLANEOUS FUNCTIONS for the INTRUSION TRANSCEIVER MODULE/ITM menu item as appropriate.