ANTENNA RING
The antenna ring (16/65) is installed around the ignition switch. The antenna ring is used to allow the central electronic module (CEM) to communicate remotely with the ignition key.
The antenna ring comprises a modulation circuit and a communication circuit. The modulation circuit converts signals between the central electronic module (CEM) and the communication circuit. The communication circuit is used to communicate with the key.
When the central electronic module (CEM) activates the antenna ring, a magnetic field is generated around the antenna ring. This magnetic field is converted in the key to an electrical current, which means that the key does not require further electrical supply.
Scheme 119
There is a communication circuit in the ignition key, known as a transponder. This circuit is supplied with power from the magnetic field that is formed around the antenna ring when the central electronic module (CEM) activates the antenna ring. Consequently, the transponder is not dependent on a further power supply.
In order for the key to be used in the vehicle, a code in the key must be entered by the central electronic module (CEM). When the vehicle is delivered from the factory, two keys are normally programmed. When a key has been programmed for the central electronic module (CEM), the key is locked and cannot be programmed for another vehicle.