The majority of keys to cars built after 1995 contain transponder chips. Function When the car key is turned in the ignition, the engine control unit (ECU) on the car sends an electronic message to the key, and it will allow the car to start only provided it receives the correct message back.
Advantages and Disadvantages
The technology involved in programming keys to specific vehicles has led many manufacturers and insurance companies to consider cars with transponder keys to be virtually theft-proof. There are many reports, however, of thieves finding ways around the system, sometimes simply by towing the car away, or by using a bypassing machine. The perception of being theft-proof has caused problems for some owners, as it can be more difficult to convince an insurance company if the car actually is stolen.
Other Uses of the Technology
Besides being used to start cars, transponder technology can also be found in a variety of other applications. These include wireless alarm keys, garage or gate opening remote controls, and wireless house-entry systems. More recent advances in the technology have led to the development of keyless entry and starting systems. With these systems, the signal is continually sent out from the fob, and as it’s in range of the receiver, the doors will be unlocked and car can be started with a push-button ignition. If the key is removed from the active range of the vehicle, the doors will lock automatically and an immobilizer system will be activated.