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VIN Diesel

What’s in a VIN (Number)?

Most people are aware that every vehicle has a unique identifier known as a VIN, or Vehicle Identification Number. Which means calling it a “VIN Number” is redundant. But in any case, you can get quite a lot of information about a vehicle by understanding its VIN.

The United States first began using VINs around 1954, but there was no standard among manufacturers for what each digit should mean. In 1981, the National Highway Traffic Safety Administration (NHTSA) standardized the format and required all new vehicles to have a 17-digit unique identification number. This number allows potential buyers to find history on a given vehicle, law enforcement to check the authenticity, and manufacturers to trace where and when a vehicle was built in case any defects are identified. Let’s take a look at what each piece of the VIN represents.

The first three characters in a VIN are known as the World Manufacturer Identifier, or WMI, with the first character generally referring to the country of origin, the second referring to the manufacturer, and the third to a category of vehicle. At its simplest, a WMI like “1FT” tells you with a first digit of “1” that it’s a vehicle manufactured in the United States, a second character of “F” that it’s a Ford (“C” is a Chrysler, “D” is a Dodge, etc). The third character “B” is a bus, “C” is a chassis, “T” is a truck, and so on. But as vehicle manufacturing and VIN standardization have become a global operation, with many countries producing vehicles, several companies starting with the same letters (e.g., Ford, Freightliner or Fiat) and many American manufacturers building vehicles in other countries (e.g., “SF” for a Ford built in the UK), deciphering the WMI has become a lot more complicated. You can find many of the combinations through online resources or purchase the official WMI standard from The Society of Automotive Engineers (SAE) who assigns these identifiers to countries and manufacturers.

For our purposes, there are just a few WMIs common to the US trucking industry. The Federal Highway Administration (FHWA) classifies trucks into 8 categories based on their gross vehicle weight rating (GVWR): light duty trucks (1-2), medium duty (3-6) and heavy duty (7-8). The trucks primarily responsible for keeping America’s freight moving are Class 7 trucks weighing between 26,001 and 33,000 pounds, and Class 8 trucks weighing 33,001 pounds or more. Among the nearly 4 million Class 8 trucks in operation, there are several common makes and models on the road today, with one clear favorite.

So, in our illustration at the top of this page, the (hypothetical) VIN tells us that we’re looking at a Peterbilt truck manufactured in the United States. The next five characters of the VIN lay out the vehicle description section (VDS) and lists features according to each manufacturer’s unique system. These generally refer to things like the vehicle’s brake and restraint system, the chassis and body type, and have so many millions of potential combinations and permutations, it would be impossible to list them here. One North American convention, however, is that the 8th position usually (but not always) denotes the engine type: its displacement, number of cylinders, fuel type, etc. In our example, however, Peterbilt uses the 6th position for the engine description. These vehicle description codes aren’t always published, but you can often find them at dealerships for a particular manufacturer, and some VIN guides for passenger vehicles can be found online, such as the Ford resources here.


That brings us to the 9th position, the “Check Digit,” which has a whole calculation system unto itself, so check back here for our next post, and be sure to subscribe below for future updates.