In today’s market there are several types of car keys. For example, there are the standard metal keys, transponder keys, fobs, proximity keys, and Vehicle Anti-Theft System (VATS) keys. The metal and transponder keys come in two forms: regular cut and laser cut.
A metal key is a mechanical key that will only start your car if you insert it into the ignition and turn it. The only way to prevent someone unwanted from using your metal key is to mechanically disable the ignition’s ability to turn.
A transponder key has two protections against misuse. The first is that there are mechanical wafers that prevent the ignition cylinder from turning. The second is that there is a computer chip located in the plastic head of the key that is connected to the car’s immobilizer (called BCM). If the car’s computer can sense the chip code then it will allow the car to start. But if the system does not sense the chip then the key will turn in the ignition, but the car will not start.
A fob key is a combination of the transponder key without the metal blade and a remote control. A fob looks like a remote control in that it has buttons you can use to lock and unlock the doors. A car with a fob key does not have a place where a standard metal key would go into the ignition, but instead includes a place to insert the remote control to start the car. The driver usually turns the fob in the ignition, which allows the car’s computer to recognize the computer chip in the fob and deactivates the immobilizer.
Proximity keys include a proximity transmitter that is incorporated into the remote control. The car’s computer recognizes the proximity transmitter, and when the key comes close to the car the driver can open the car doors by touching them or pressing a button. The driver can also start the car by pushing a button, even when the proximity key is in the driver’s pocket or bag.
The final type of key is a VATS key, which is an older key that was only made by GM for limited models and years. A VATS key has a chip located in the middle of the key that works when it comes into contact with the ignition.