The radio remote control system consists of a key transmitter and a receiver module installed in the vehicle.
The radio signals emitted by the key transmitter are received via an antenna installed in the rear window shelf.
All radio telegrams are coded and feature a constantly changing code so as to prevent manipulation and thus unauthorized opening of the vehicle.
Due to the different approval regulations for radio equipment in various countries, there are two different versions of the overall system (key, receiver module and antenna).
Key transmitter ECE version, 433 MHz
Key transmitter US version, 315 MHz
The key transmitter is powered by two commercially available lithium batteries. The three buttons on the key transmitter trigger, depending on how long they are pressed, various actions in the vehicle.
All radio remote instructions are encoded by means of a constantly changing code in order to prevent tampering in the system.
Key transmitters without an EWS transponder (electronic immobilizer) feature an LED as a function indicator.
The LED lighting briefly after a button has been pressed signals that the remote command has been sent.
If the button is held pressed (to open/close the windows) the LED flashing indicates that instructions are constantly being sent.
If the LED does not light after pressing a button, either the batteries in the transmitter are discharged or the transmitter is defective.
No LED is installed on key transmitters with an EWS transponder.
The charge of the batteries in the key transmitter is monitored every time a button is pressed.
The key transmitter signals the battery status to the receiver module if the voltage reaches a lower limit value. The receiver module passes on this message via the K-bus to the IKE. After opening the driver's door, a corresponding check-control message appears in the IKE display.
The batteries in the key transmitter should be replaced when a corresponding message appears.
The function indicator (LED) on key transmitters without an EWS transponder no longer lights when the battery voltage drops below the required value.
A self-test can be carried out on key transmitters without an EWS transponder (electronic immobilizer).
In order to carry out this test, press and hold button 1 and button 3 simultaneously.
The transmitter is OK. when, after approx. 1 second, the LED in the key lights up for approx. 1 second.
If the LED does not light, first replace the batteries in the key. Then repeat the self-test. The key transmitter should only be replaced if the LED still does not light.
No LED is installed on key transmitters with an EWS transponder.
The data sent by the key transmitter are received and decoded by the receiver module via a radio antenna.
The received instruction is sent via the K-bus to the general module of the ZKE III where it is carried out (e.g. unlock central locking and disarm DWA).
The minimum range for instructions to the central locking system is 10 m.
The range is limited to a radium of approx. 5 m for the convenient opening and closing of the power windows and sunroof. The range is reduced for safety reasons.
During initialisation, the range is reduced to such an extent that this function must be carried out in the vehicle with the key transmitter pointing in the direction of the antenna (rear window shelf).
Important!
Particular care must be taken to ensure the antenna connected to the receiver module is fitted correctly to provide clear reception. It must be firmly plugged into the receiver module and must be routed under the trim panel in the rear window shelf transversely with respect to forward direction. The part of the antenna without black insulation cover must be located in the centre of the rear window shelf.
The initialisation procedure allocates the key transmitter to the receiver module. During initialisation, a code is generated in the key transmitter and then transferred to the receiver module. The code is stored in the key transmitter and in the module. The receiver module recognizes the keys belonging to the system on the basis of this code. Only commands from these keys are then carried out.
A maximum of 4 keys can be initialised for each vehicle. The codes of all other keys are deleted when a key is re-initialised. This means that all the keys of a system must be initialised simultaneously.
During initialisation, the reception range is reduced to such an extent that this function must be carried out in the vehicle with the key transmitter pointing in the direction of the antenna (rear window shelf).
Repeat the procedure as of Point 3 (= press and hold button 2 on key transmitter) to initialise the other keys. Terminal R must not be varied during this procedure.
The initialisation procedure is terminated if terminal R is switched on.
Note
The code stored in the key transmitter is lost if the key transmitter is disconnected from the voltage supply for a prolonged period. For this reason, the key batteries should be replaced within 1-2 minutes.