In 1981, car manufacturers started assigning a unique, 17-character code to each vehicle that is built, which is used for various purposes, but mostly for verifying the legitimacy of vehicles. Governments and law enforcement agencies use it to identify stolen vehicles, and car owners need it when they take their cars to a mechanic, and it's also useful when buying a used car, so that you can run a vehicle history report. The insurance industry often uses vehicle identification numbers, as well. VINs are usually engraved on aluminum plates, cast or stamped, as a bar code, or in label form, and they can be found on a car's steering column, doorjamb, driver's door, passenger side door, dashboard, as well as in a vehicle's maintenance book and title.
Vehicle identification numbers are an important tool for law enforcement agencies in their efforts for preventing car theft and hijacking, tracking down car thieves and helping consumers avoid buying stolen vehicles. Since a lot of used vehicles being sold nowadays have been previously stolen, doing a VIN check is very important when buying a used vehicle. The most reliable way for making sure that you have the correct VIN is obtaining it directly from the vehicle, instead of the car's title, since the number found on that document may not be written down correctly.
Car thieves tamper with the VIN number of a stolen vehicle so that they can sell its parts, license it under a new identity, or get the vehicle out of the country. A VIN can be changed in various ways, but the most-commonly used methods include removing of the part of the car where the VIN is located and replacing it with a new part, grinding, or changing one or multiple numbers or letters of the VIN. That is why, when buying a used car, you should always check the places where a VIN is usually located, and look for signs that indicate it has been tampered with.
If you do a VIN check on a vehicle you are interested in buying, you can find out by how many people it has been owned previously, and whether it has been used as a rental car, which is an important factor when determining the overall condition of the car.
There are various websites that offer VIN checks for a certain fee, where all you need to do is enter the VIN you have obtained from a seller of a used car, and you'll get a full report containing detailed information about a car's history. Next year, the NHTSA will create a VIN recall database accessible via the web, and all car manufacturers will have to contribute to it, so that people who buy used cars can get information on the vehicles they are interested in by entering their VIN numbers.