Operation

OPERATION

The security indicator gives an indication to the vehicle operator when the Vehicle Theft Alarm (VTA) is arming or is armed. This indicator is controlled on the instrument cluster circuit board by a hard wired input to the cluster from the Body Control Module (BCM) on the VTSS indicator driver circuit.

On vehicles equipped with the Sentry Key Immobilizer System (SKIS), the security indicator also gives an indication to the vehicle operator of the status of the SKIS. The SKIS function of this indicator is controlled by the BCM based upon BCM programming and electronic messages received by the BCM from the Sentry Key REmote Entry Module (SKREEM) (also known as the Wireless Control Module/WCM) over the Programmable Communications Interface (PCI) data bus.

The security indicator Light Emitting Diode (LED) receives battery current on the instrument cluster electronic circuit board through a fused B(+) circuit at all times. Therefore, the LED can be illuminated regardless of the ignition switch position. The LED only illuminates when it is provided a path to ground by the BCM. The BCM will turn ON the security indicator for the following reasons:

- Bulb Test - Only on vehicles equipped with the SKIS, each time the ignition switch is turned to the ON position the SKREEM sends an electronic message to the BCM to illuminate the security indicator for about three seconds as a bulb test. The entire bulb test is a function of the SKREEM.
- VTA Indication - During the 16 second VTA pre-arming function, the BCM will flash the security indicator ON and OFF repeatedly at a steady, fast rate to indicate that the VTA is in the process of arming. Following successful VTA arming, the BCM flashes the security indicator ON and OFF continuously at a slower rate to indicate that the VTA is armed. The security indicator continues flashing at the slower rate until the VTA is disarmed.
- SKIS Indicator Lamp-On Message - Each time the BCM receives an electronic SKIS indicator lamp-ON message from the SKREEM, the security indicator will be illuminated. The indicator can be flashed ON and OFF, or illuminated solid, as dictated by the SKREEM message. The indicator remains illuminated solid or continues to flash until the BCM receives a lamp-OFF message from the SKREEM, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Communication Error - Only on vehicles equipped with the SKIS, if the BCM receives no lamp-ON or lamp-OFF messages from the SKREEM for 20 consecutive seconds, the security indicator is illuminated by the BCM. The indicator remains controlled and illuminated by the BCM until a valid lamp-ON or lamp-OFF message is received from the SKREEM.
- Actuator Test - Only on vehicles equipped with the SKIS, each time the instrument cluster is put through the actuator test, the security indicator will be turned ON, then OFF again during the bulb check portion of the test to confirm the functionality of the LED and the indicator control circuitry.

The BCM circuitry controls the security indicator through the VTSS indicator driver circuit whenever the ignition switch is in the OFF position and the VTA is arming, armed, or triggered. On vehicles equipped with the SKIS, the SKREEM performs a self-test each time the ignition switch is turned to the ON position to decide whether the SKIS is in good operating condition and whether a valid key is present in the ignition lock cylinder. The SKREEM then sends the proper lamp-ON or lamp-OFF message to the BCM. If the BCM flashes the security indicator upon ignition ON, or turns ON the security indicator solid after the bulb test, it indicates that a SKIS malfunction has occurred or that the SKIS is ineffective.

The hard wired VTSS indicator driver circuit between the BCM and the ElectroMechanical Instrument Cluster (EMIC) may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, for proper diagnosis of the VTA, the SKIS, the SKREEM, the BCM, the EMIC, the PCI data bus or the electronic communication related to security indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.