Every street-legal vehicle has a unique vehicle identification number. The VIN is an alphanumeric code that identifies the make, model and specifications of any vehicle. Since VINs became standardized by the National Highway Traffic Safety Administration in 1981, these 17-character codes provide a consistent set of information across manufacturers. Each character in a VIN corresponds to specific details about the vehicle that can be helpful for finding the right car parts, checking recall status or tracing maintenance history.
Deciphering a VIN
Standardized VIN codes consist of numbers and capital letters. A more specific answer to the question what is a VIN number is that each character provides information about a vehicle. The first character indicates where the vehicle was built and the second and third characters identify the manufacturer. The fourth and eighth characters indicate the brand and engine size or type. The ninth character is a check digit used for validation. The tenth character corresponds to the model year and the eleventh identifies the plant that assembled the vehicle. The last six characters of a VIN are the vehicle serial number.
Validating a VIN
VINs are intended to be used for validating vehicles. In addition to being a unique identifier, a VIN also provides a basis for a calculation in a VIN-check algorithm. First, transliteration is performed to turn alphabetical characters into numbers. A weight factor must also be calculated for each position. Each value and its weight are multiplied and the products are added together to yield a sum that is then divided by 11. The remainder is the check digit, which should correspond to the ninth character in the VIN. This code and calculation is intended to ensure that a vehicle is legitimately manufactured and sold. A used car that has a cloned VIN may be stolen.
Using a VIN
Doing the math necessary to verify a VIN will only determine whether the code is authentic. This process is performed by automotive manufacturers, insurance companies and motor vehicle registration departments. A VIN lookup is necessary to verify the year model and build of a particular vehicle. This number is also helpful for maintenance purposes and determining the ownership history of a vehicle. Certain portions of the number are useful for selecting replacement parts or for determining whether a vehicle is involved in a recall. If a vehicle experiences issues that may be related to a manufacturing defect, the owner can report the VIN to the National Highway Transit Safety Administration for investigation into whether a recall of similar models will be necessary.
On most vehicles, a VIN can be found on the corner where the dashboard meets the windshield or inside the door post on the drivers’ side door. This number may also appear on the front of the engine block or the front end of the frame. To obtain this number without access to a vehicle, check insurance documents, the vehicle title or other registration records. The most useful way to decipher a VIN is to look up the details associated with this identifying number.