Today most car keys
are in fact transponder keys. The word transponder is in fact short for transmitter and responder. It refers to the very small electronic chip which is called a non-volatile memory. This chips unlocks a vehicle immobiliser when the key is injected in the ignition switch
to start the engine of the car.
When you insert the key into the engine control unit (ECU) or ignition switch, the car sends an electronic message to the key. The latter responds in code. The vehicle will only start if it receives the correct message back. Therefore if you lose your car key
, a new one needs not only to be cut correctly but also programmed using special equipment.
Recently more and more cars have a remote keyless entry system (RKS) also known as keyless entry or remote central locking. Generally a car key for a remote keyless entry system contains a number of buttons allowing you to lock and unlock the doors with a certain radiance of the car.
The first cars with remote keyless entry systems were issued by Renault with General Motors quickly following suit. The remote keyless entry system developed further into the remote keyless ignition system (RKI) which replaces a traditional car key altogether. Where a keyless entry system allows you to electronically lock and unlock your car, a smart key for a RKI allows you to start the engine without taking the remote keyless entry fob out of your pocket.
Due to the individuality of both transponder car keys
with a remote control and key fobs, special equipment is necessary to program these keys.