Body Control Module (BCM)

The CTD system is an internal function of the Body Control Module (BCM) which utilizes class 2 serial data and various switch input information to perform CTD functions. When the BCM detects an unauthorized entry, the BCM applies ground to activate the horns and exterior lamps. The BCM has five basic modes:, disarmed, standby, delayed, armed, and alarm for operating the CTD system. The different modes are described below.
1. The BCM has the CTD system in a disarmed mode until the following conditions are detected:
^ Ignition key turned to the OFF position
^ Any door open
^ Doors locked by either the power door lock switch or the LOCK button on the transmitter
2. The BCM enters the standby mode when the above conditions are detected. In standby mode the BCM commands the instrument cluster to illuminate the SECURITY indicator via the class 2 serial data circuit. If all the doors are closed and the LOCK button on the transmitter is used, the BCM enters the delayed mode.
3. When the last door is closed, the BCM enters the delayed mode for 30 seconds. In delayed mode the BCM commands the instrument cluster to illuminate the SECURITY indicator on steady via the class 2 serial data circuit.
4. After 30 seconds, the BCM enters the armed mode. In armed mode the BCM commands the instrument cluster to turn off the SECURITY indicator via the class 2 serial data circuit. Any forced entry activates the alarm mode.
5. When the BCM detects a forced entry, the BCM enters the alarm mode. The BCM applies ground to activate the horn and exterior lamps for 30 seconds, via a class 2 message. This is followed by a three minute time-out with the horn no longer active. If no new intrusions are detected after the time-out, the horn is not active. The system must be disarmed or the intrusion condition removed after the time-out for the system to exit alarm mode.