The interior protection system is based on a movement detector (microwaves) that detects movements in the vehicle interior and sends corresponding signals to the BC1 (general module).
A transmitter aerial is integrated MuW (Multiplex Microwave Sensor) 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.
There are a total of four sensors fitted at each seat position in the vehicle interior. These include a master controller MuW as the control element and as interface to the Body Controller (BC1) and three slave MuWs.
Movements in the vehicle cause a change in the reflections and trigger an alarm via the BC1.
For insurance reasons (depending on national legislation), all windows must be closed at all times also when the convertible top is open.
NB - new: The convertible top must always be closed to guarantee adequate protection of the inside of vehicle!
Large metal objects (e.g. metal case) shield the electromagnetic waves so that in certain areas no alarm can be recognised due to shadow effects.
When the convertible top is 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.
The interior monitoring is activated or deactivated by the body controller BC1 by switching on/switching off the 12-Volt power supply for the MuW. The STDWA line activates and deactivates the tilt alarm sensor and the siren.
Interior monitoring begins 30 seconds after activating the antitheft alarm system. The interior is not monitored when a vehicle door or the luggage compartment lid/engine bonnet is open. Opening the boot (trunk) lid or convenience closing of the windows interrupts the interior protection function.
If the MuW assembly detects a triggered alarm, this status is signalled to the BC1 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 activating the anti-theft alarm system, the interior protection system control unit master MuW and the three slave MuWs run a self-test. If a fault occurs here or everything is OK, this is reported across the INRS line to the BC1. The BC1 stores a fault entry for a defective interior motion sensor (e.g.: Microwave sensor driver's door).
The self-test can also be initiated manually.
To do so, run the test module at Body -> Locking and security functions -> Anti-theft alarm system -> Self-test of microwave sensors
A faulty module is not activated in order to avoid false alarms being triggered.
Definition of the slave sensors (defining which sensor is slave 1 or 2 or 3) is by means of external wiring at pin 2.
Passenger's door sensor (slave 1): pin 2 to +12 V (terminal 30)
Rear right sensor (slave 2): pin 2 to earth (terminal 31L)
Rear left sensor (slave 3): pin 2 not wired