A transponder is small chip in your car key, made to control the immobilizer in your car. Often people do not realize that their key has a transponder as they are so small. The transponder exists of a block or tube and gives a signal to the car when the ignition is started.

The transponder communicates with the car as you turn the key in the ignition lock. It has to be programmed to the car to be able to start. An existing transponder that you transfer to a new housing will still work, but if you replace it for a new one, youíll have to program it again. The dealer can program the original transponder for you, but there are also various key specialists who have the equipment to attend to this.

The older versions mostly have a transponder which can be copied. You do need the right equipment for this, but not the car itself. The newer versions always need to be programmed to the car, these have a so-called ëchanging codeí. Simply said, the transponder assembles a new electric code every time when turning the ignition on and off.

Technology is permanently in motion and nowadays it is even possible to extract information from the transponder:

• VIN of the associated vehicle
• what the mileage was when the key was last used
• It is even possible to give preference of (for example) seat position.

These transponders are in most cases fragile and expensive, so be careful when transferring them.