How Are Car Keys Programmed?

By Liz Jacobs

Programing a car key isn't something that just anyone can do. That's why replacement car keys can be expensive. When you buy replacements keys from the dealership, you are not just paying for the cut car key, but for the programming of the small electronic chip inside of the key.


Programmed car keys are also known as transponder keys. Transponder keys work because of a small microchip in the top of the key that transmits a digital code to the car's ignition. Without the right key, the car's engine will not start. The dealership programs the chip with a special tool. According to Philadelphia Locksmith, some car keys can be programmed with very simple steps while others need special diagnostic equipment to be connected to the car's computer.


Programming codes and procedures vary greatly depending on the make and model of the car. That's why some replacements keys cost much more than others. However, programmed car keys have cut down on auto theft. Because the programming procedures can be complex, transponder replacement keys are not as easy to obtain as regular car keys. According to Philadelphia Locksmith, some locksmiths are able to create replacement transponder key for some cars, however locksmiths have to invest a lot in the special equipment it takes to make these keys. Other transponder keys require essential information or pins that are too difficult for the locksmith to obtain.


If a locksmith says he is able to make a replacement key for your car, make sure you test the key multiple times before leaving the locksmith. That way you can make sure the chip inside the key is programmed properly.Beware of a key that is getting very old or sticking as you put it into the ignition. Sometimes the program inside of the chip can fail even as you are driving. That's why its important to keep a master key from the dealer in addition to the key you use for everyday driving. If you have master key, you may be able to cut down on the cost of a replacement key.

Expert Insight

Even if you have an older car that does not have a transponder key, according to Autotransponder, it is possible to make your key into a transponder key using a kit you can purchase. Doing so will protect your car against theft


With the right equipment, you may be able to program a spare car key yourself. However, you will still need the master key with the dealership's complex codes.