CarScan

What a VIN says — and what it never says

Seventeen characters tell you what the car was BUILT as. They tell you nothing about what happened to it afterwards. Start with the check digit: it catches a single mistyped character before you drive across the country to see the car.

Spaces, dashes and lower case are fine. The letters I, O and Q are never used in a VIN — we read them as 1 and 0, so a mistake in copying does not stop the check.

How the seventeen characters are laid out

PositionWhat it is
1Region and country of the plant
2–3Manufacturer. Together with the first character this is the WMI
4–8Set by the manufacturer: body, engine, trim. No common decoding
9Check digit — the only character that can be verified by arithmetic
10Model year, on a thirty-year cycle
11Assembly plant, in the manufacturer's own coding
12–17Serial number of this particular car

What a VIN never tells you

Mileage, accidents, repairs, outstanding loans, how many owners there were — none of that is in the number. Those live in separate registers, and each country has its own. Anyone promising to read them from seventeen characters is selling you a guess.

What does tell you about the car's life are its own fault codes, its readiness monitors and its freeze frames. That is what an adapter reads. What a scanner shows before you buy.