Decoding a Car’s VIN

One thing our cars have in common (unless you built your car in your own backyard, of course) is an automotive specific serial number – better known as a Vehicle Identification Number (VIN).

Originally, car manufacturers utilized their own, proprietary VINs.  It was literally anything goes, as one manufacturer’s VIN system might have had nothing in common with any other manufacturer’s system. These homegrown VINs, introduced in 1954, disappeared with the adoption of standardized systems that had been mandated with the start of the 1981 model year through the regulatory powers of the National Highway Transportation Safety Administration (NHTSA).

The systems introduced in 1981 are all based on two standards published by the International Organization for Standardization (ISO): ISO 3779, published in 1979, and ISO 3780, published in 1980.  The versions utilized by both the United States and European Union are based on, and compatible with the ISO standards, but technically, should be considered standards that are competitors of the ISO ones.

And the NHTSA hasn’t remained static in its use of the VIN.  It has added new regulations to expand VIN usage: first in 1987, with a requirement that any model designated as a “high-theft” car have major vehicle components and parts marked with the VIN; and again in 1994, when the 1987 requirements were extended to every car.  The 1994 regulations also expanded the total number of components and parts that must be marked with the automobile’s VIN.

All of these post-1981 VINs consist of 17 digits; each represented numbers 0 through nine or letters.  The letters (I), (O) and (Q) were expressly disqualified as to avoid any potential confusion between them and the numbers 0 or 1.  Interestingly enough, they allowed “S” to be used, despite possible transcription and reading errors that might allow “S” to confused with “5”.

However, despite potentials for confusion, most state DMVs or DOTs, as well as the majority of car insurance companies, have well developed and highly successful VIN computer-based testing algorithms to identify any potential incorrect VINs.  So any transcription errors such as the “S” and “5” usage many have the potential to create will likely be identified as such.

Here in the United States, there are two different VIN standards in use.  One version is reserved for niche-builders of automobiles that produce less than 500 cars per year.  The other version is utilized for all other car manufacturers that produce more than 500 cars each year.

Before we go further into the digit positions and their meanings, it’s important to note that VINs have also been applied to many applications beyond just identifying a car and its ownership through state DMVs/DOTs.

For example, if your car is involved in an accident where a police report is filled out, the VIN has been recorded to identify and record its involvement.  The same goes for an insurance claim – the VIN and transaction are recorded.  These records are then data harvested.  Yes, police departments not only record and keep this data; they also share it with car insurance companies and sell it to third parties such as CarFax.

And CarFax isn’t the only one buying VIN based data.  Companies like Consumers Reports and Experian also provide VIN-based reports on cars that include car’s that have been bought back from the consumer by the original manufacturer through a lemon law dispute, odometer inconsistencies, and many more problems and potential issues.

Let’s get back to the digits of a VIN.  For all manufacturers who produce more than 500 cars a year, here is the basic breakdown utilized in the United States.

Digits 1-3 are utilized for the World Manufacturer Identifier (WMI) code.  Some examples include: 1G is the two digit designation assigned to represent General Motors.  1G1 (with the 1G representing GM) is the WMI code for Chevrolet.  So from three digits, we can glean that the manufacturer is General Motors, and the specific make is Chevrolet.  In our example above, JS2 represents that the car was built in Japan by Suzuki.

Digits 4-9 are the Vehicle Descriptor Section (VDS), where things such as model, body style, are unique to the specific manufacturer, as each has its own system to denote car descriptions.  One common occurrence is that most manufacturers utilize the 8^th digit to identify the specific engine type in the car, as some models feature multiple engine choices.  The 9^th digit is normally used as a check digit, which is used to test the validity of the VIN.

Digits 10-17 are the Vehicle Identifier Section (VIS).  Both digits 10 and 11 have nearly consistent usage despite manufacturer.  Digit 10 of a VIN denotes model year, and digit 11 denotes assembly plant, and it is required in North America.  The remaining digits are simply sequential numbers representing and identifying build number, although some manufacturers also utilize them to denote options and other specifics about the car as well.

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