What is a transponder?
Car keys have become more difficult and expensive to replace since the introduction of Immobiliser Systems, which came into existence around 1997. If your vehicle was manufactured BEFORE 1997, its more than likely that a standard brass key will operate your ignition barrel and start your engine.
If your vehicle was manufactured after 1997, your car most likely has an Immobiliser System built into your vehicle, which means a standard key will not start your engine.
When you turn your ignition on a copper coil antenna around ignition barrel emits a magnetic field, which creates enough power to induct a tiny voltage into the antenna of the transponder chip or RFID chip located in the head of the key. Once the chip is powered up the cars antenna is then able to read the data or the ID number off the chip located in the key and relay this code to the Engine Control Unit, or immobiliser unit inside your vehicle. If the code matches up with the information that is stored in the immobiliser/Engine Control unit, the vehicle will start. If the RFID chip has the wrong coding or if a standard key is turned in the ignition, the vehicle will not start. More often than not, trying to start the car with and unprogrammed key could shut the engine ECU down and completely immobilise your vehicle!