Sensor, Intrusion Module: Operation

The intrusion module sensors are both completely controlled by the microcontroller of the Intrusion Transceiver Module (ITM). While the Vehicle Theft Alarm (VTA) is armed, the ITM generates ultra high frequency sound bursts into the vehicle interior through the ultrasonic transmit transducer and monitors the return signal input through an ultrasonic receive transducer of each of the intrusion module sensors. The ITM logic uses an algorithm to detect movement in the vehicle interior through modulation of the ultrasonic echo that occurs due to the Doppler effect.

The ITM also monitors the current draw of the sensor circuits to detect problems with the sensors or the sensor circuits and will store a Diagnostic Trouble Code (DTC) for any fault that is detected.

The hardwired circuits of the intrusion module sensors 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 sensors or the electronic controls and communication between modules and other devices that provide some features of the VTA. The most reliable, efficient and accurate means to diagnose the intrusion module sensors or the electronic controls and communication related to sensor operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.