Function

The infrared remote control can only be used in combination with the vehicle to which it belongs, because the remote control and control module installed in the vehicle are matched to one another.

The remote control transmits the signal to the receiver in the form of an infrared light beam. The receiver picks up this light beam, filters out extraneous light, amplifies the signal and transfers it to the control module via a control line.

The transmitted signal consists of a fixed code, which is encrypted additionally by a computer. This additional encryption changes each time it is used. This makes it impossible to decode the signal.

The control module decodes the signal and actuates the central locking, interior central locking and ATA when the fixed code is correct. Simultaneously the control module is reset to the next signal to be transmitted inhibiting the previous signal.

If the remote control is actuated outside of the reception range, the current signal changes in the remote control, however, not in the control module in the vehicle. When the remote control is used again within the reception range, the signal from the remote control does not coincide with that expected by the control module in the vehicle. However, since the control module can extrapolate 250 switching operations, it adjusts itself to the current signal from the remote control.
If the remote control is actuated more than 250 times outside of the reception range, it is necessary to resynchronize the remote control. Service and Repair

Desynchronization
If a remote control key is lost the alternating code component of the signal can be desynchronized on vehicles as of 12/93 using the hand-held tester. This means that is only necessary to replace the mechanical locks. when a remote control key is lost. All remote control keys for this locking system must then be resynchronized. Service and Repair