The interior protection system is based on a movement detector (ultrasound) that detects movements in the vehicle interior and sends corresponding signals to the general module 5.
The interior protection is fitted in the headlining.
A transmitting aerial is integrated in the interior protection system control unit for the purpose of generating an electromagnetic field in the vehicle. The reflections are received by the receiving aerial in the control unit and transferred to the integrated electronic circuitry for evaluation.
Movements in the vehicle cause a change in the reflections and trigger an alarm via the general module 5.
For insurance reasons (depending on national legislation), all side windows must be closed at all times. This requirement also reduces the risk of a false alarm, e.g. by persons leaning on the car.
Large metal objects (e.g. metal case) shield the electromagnetic waves so that in certain areas no alarm can be recognized due to shadow effects.
When the side windows are open, an alarm may be triggered in the following instances:
The alarm triggering is stored in the alarm menu of the body electronics control module.
When the antitheft alarm system is armed, the interior monitoring facility is activated by the general module 5 via the STDWA line and deactivated when the system is disarmed (the same line also activates and deactivates the tilt alarm sensor and siren).
Interior monitoring begins 30 seconds after activating the antitheft alarm system. The interior is not monitored when a vehicle door or the boot (trunk) lid is open. Opening the luggage compartment lid or convenience closing of the windows interrupts the interior protection function.
If the interior protection system control unit detects a triggered alarm, this status is signalled to the general module via the INRS line.
In order to avoid false alarms being triggered under unfavourable ambient conditions, the interior protection function can be switched off with the antitheft alarm system activated as follows:
After the anti-theft alarm system has been activated, the interior protection system control unit runs a self test. If a fault occurs, it is signalled via the INRS line (interior protection system control unit 1). A fault code for defective interior protection is stored in the general module (display: interior protection 1).
A faulty module is not activated in order to avoid false alarms being triggered.