Vehicle Theft Alarm: Notes

The ElectroMechanical Instrument Cluster (EMIC) is used on this vehicle to control and integrate many of the functions and features included in the Vehicle Theft Alarm (VTA). The EMIC is also sometimes referred to as the Cab Compartment Node (CCN). In the VTA system, the EMIC/CCN receives inputs indicating the status of the door ajar switches, the ignition switch, the liftgate ajar switch, the flip-up glass ajar switch, and the power lock switches. In vehicles built for certain export markets where it is required, the hood ajar switch provides a hard wired input to the Front Control Module (FCM) and both the FCM and the intrusion module provide electronic message inputs to the EMIC over the Controller Area Network (CAN) data bus. The EMIC processes the information from all of these inputs, internally controls the security indicator as appropriate, and sends electronic messages to the FCM over the CAN data bus. The FCM internally controls the output to the hazard warning lamps and sends a control output to energize or de-energize the horn relay as appropriate. On vehicles with an intrusion module, the horn output of the FCM is replaced by an output of the siren module that is controlled by the intrusion module.

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 EMIC/CCN, the FCM, the intrusion module, the CAN data bus or the electronic message inputs and outputs used to provide the electronic features of the VTA. The most reliable, efficient, and accurate means to diagnose the EMIC/CCN, the FCM, the intrusion module, the CAN 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. 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.