VIN: Reading, checking and using the vehicle identification number

Why a VIN has 17 characters

Before 1981 every manufacturer numbered vehicles to its own pattern. The standards ISO 3779 and ISO 3780 settled on a common format: 17 characters in three sections, no separators. Since then any vehicle can be named unambiguously without asking its maker — which is exactly what makes the VIN the anchor of every vehicle and parts database.

The letters I, O and Q never appear in a VIN. They could not be told apart from the digits 1 and 0. If you find an O in a record you are almost certainly looking at a 0 — a typing error worth catching before any paid lookup.

The structure: WMI, VDS and VIS

WMI — the first three characters

The first character names the world region, the second the manufacturer within it, the third the vehicle type or division. A to H stand for Africa, J to R for Asia, S to Z for Europe, 1 to 5 for North America, 6 and 7 for Oceania, 8 and 9 for South America. Germany sits at W, France and Spain at V, Italy at Z, Sweden and Finland at Y.

Small-series manufacturers building fewer than 500 vehicles a year receive a WMI whose third character is a 9. For them the actual manufacturer information sits in positions 12 to 14 — search a database without knowing that and the vehicle simply will not be found.

VDS — the vehicle descriptor

Positions 4 to 8 describe the vehicle: model line, body style, engine, sometimes the restraint system. Each manufacturer defines the coding itself, and this is exactly where what you can read off a VIN without manufacturer data ends. Some European makers pad unused positions with Z — the ZZZ in a Volkswagen VIN is deliberate, not a fault.

VIS — the vehicle serial section

The last eight characters name the individual vehicle, and the final four are always digits. In North America position 10 carries the model year and position 11 the assembly plant; in Europe that coding is not prescribed, although many manufacturers follow it.

The check digit in position 9

The ninth position can carry an arithmetic check digit. It is mandatory in the United States and Canada but not in Europe, where many vehicles put a descriptor character there instead. A failed check-digit calculation is therefore no proof of a wrong VIN in Europe. It is a hint, nothing more.

1. Every character is translated into a number. Digits count as themselves, letters follow a fixed table: A=1, B=2 … H=8, J=1, K=2 … N=5, P=7, R=9, S=2, T=3 … Z=9.
2. Each value is multiplied by the weight of its position. From left to right the weights are 8, 7, 6, 5, 4, 3, 2, 10, 0, 9, 8, 7, 6, 5, 4, 3, 2.
3. All products are added and the sum divided by 11. The remainder is the check digit; a remainder of 10 is written as X.

VIN    W  V  W  Z  Z  Z  1  K  5  0  W  0  0  0  1  2  3
Value  6  5  6  9  9  9  1  2  5  0  6  0  0  0  1  2  3
Weight 8  7  6  5  4  3  2 10  0  9  8  7  6  5  4  3  2
Prod  48 35 36 45 36 27  2 20  0  0 48  0  0  0  4  6  6

Sum = 313        313 mod 11 = 5        check digit = 5

Where the number sits on the vehicle

In a dismantling yard the paperwork is often gone while the vehicle is still there. The number is usually stamped or printed in several places:

• Stamped into the body — depending on the make in the plenum chamber, the wheel arch liner, the floor pan ahead of the passenger seat or on the B-pillar.
• On the manufacturer's plate, together with permissible gross weight and axle loads.
• Visible through the windscreen at the bottom of the driver's side.
• In the registration certificate part I, field E, and in part II.

What a VIN tells you — and what it does not

A VIN on its own yields region, manufacturer and, depending on the brand, coarse model-line information. The equipment of a specific vehicle is not in the number. Gearbox type, engine code, paint colour, optional equipment and the part numbers actually fitted live in the manufacturers' databases and are merely looked up via the VIN. Anyone who „decodes“ a VIN is therefore either reading the standardised parts only or querying a data source.

That distinction is worth money in daily work. A provider that „calculates“ a full equipment list from the VIN alone is guessing wherever data is missing. For a dismantler who sells a part on that basis, the guess turns into a return.

The VIN in the dismantling yard

For an authorised treatment facility the VIN is not just a search key but a record. It appears on the certificate of destruction, it ties the accepted end-of-life vehicle to every part removed from it, and it is the one detail with which a buyer can verify fitment for themselves.

• Intake: capture the VIN, resolve the vehicle data, open a vehicle file.
• Dismantling: every removed part carries the donor vehicle's VIN — see Part identification: from removed component to sellable record.
• Sale: the VIN is the strongest fitment argument in a listing and lowers the return rate.
• Records: certificate of destruction and stock keeping hang off the same number.

Common capture errors

• O for 0 and I for 1 — those letters do not exist in a VIN.
• Spaces in groups of four introduced by copying out of a PDF.
• Confusion with the engine number or the number of the registration document.
• A truncated 17th character where an ERP field only allows 16.
• Two vehicles of the same model line in the yard and one note — the most common and most expensive mix-up.

VIN, HSN/TSN and OE number

Three identifiers, three purposes, and they are mixed up constantly. The VIN names one individual vehicle. HSN and TSN name a type in German registration law. The OE number names a part in the manufacturer's catalogue. The path from vehicle to part normally runs from the VIN through vehicle identification to the OE number and from there into the independent aftermarket.