Ultrasonic Sensor

The ultrasonic sensor is located adjacent to the left hand "B/C" post on the interior headlining and is used to detect movement within the vehicle when the volumetric function of the alarm system is active.

SELF CHECK: Each time the ignition is switched off, the BECM initiates the ultrasonic sensor to perform a self check procedure to ensure correct operation. When the ignition is switched off the sensor is activated for a period of 60 seconds or until the driver's door has been opened and closed or the vehicle has been locked using the key or the remote handset.

During the self check, the sensor expects to detect the driver leaving the vehicle. If the sensor detects no movement but a driver's door open and close sequence has occurred, the BECM logs this as a sensor failure. If five consecutive failures are logged, the BECM will log a sensor failure and "ALARM FAULT" will be displayed on the message center when an attempt to superlock the vehicle is made or the ignition key is inserted in the ignition switch.

When a valid self check sequence occurs, the BECM will set the log counter back to zero. If no movement is detected during a self check and a driver's door open and close sequence has not occurred, the BECM will not count this as a failure or a valid self check.

NUISANCE TRIGGERING: When a valid superlock request is received and all windows are closed and set, the BECM will wait 5 seconds before activating the ultrasonic sensor to allow the air in the vehicle to settle. After the 5 second period, the BECM monitors, via the sensor, for movement within the vehicle.

If movement is detected in this 10 second period the alarm will be triggered and superlocking will be prevented. If no movement is detected, the vehicle will superlock and volumetric sensing will be active to monitor the vehicle interior.