With Code 882a

Interior Motion Sensor Protection Scope:

The infrared interior motion sensor is a supplement to the ATA system providing additional protection against forced entry through the side windows.

In comparison to models 202 and 140 the following modifications are present:
- No separate control module for interior motion sensor
- Optical system as well as evaluation in each sensor
- Sensor signals tripping via ground signal to pneumatic system equipment (PSE), into which ATA is integrated
- Deactivation for one locking operation via voltage coded switch in center console
- When alarm is tripped the interior lighting is switched on when the door contact switch in the dome lamp is switched to "ON".

Function
The left and right infrared transmitter and receiver units (IR) (A26/4, A26/5) transmit infrared light along the side windows into the interior of the vehicle from infrared transmitter diodes through a lens system.
The infrared light is reflected from the interior and converted into an electrical voltage by the receiver diodes. When an attempt is made to enter the vehicle, e.g. by breaking a side window, the reflection of the IR light changes.

This feature becomes active approx. 60s after locking the vehicle.

These changes in the reflecting are analyzed and evaluated by the control modules integrated into the transmitter and receiver units for the interior motion sensor (A26/4, A26/5). If the evaluation coincides with one of the stored break-in patterns, a signal is sent to the ATA control module integrated into the pneumatic system equipment PSE (A37). This signal then trips the optical and acoustic ATA alarms.


In many cases the electronic circuitry is capable of differentiating whether or not an attempt at forced entry is present. For example a jacket swinging on a clothes hook does not trip the alarm.


NOTE: However, things (e.g. insects), which move directly in front of or on the lens can trip the alarm.







Switching off interior motion sensor
The infrared interior motion sensor can be switched off in cases such as when people or animals are to remain in the locked vehicle. This can be accomplished with the resistance coded infrared (IR)/anti-towing sensor/ATA status indicator switch (S85/2) installed in the center console.
For this purpose remove the key from the steering lock and press switch (S85/2) down. The status indicator in the switch (S85/2) flickers for approx. 2s as an acknowledgment signal. The infrared interior motion sensor is automatically reactivated during the next locking operation when switch (S85/2) is not pressed previously.

Location Of Components: