VIN decoder: how to read a Vehicle Identification Number and what it tells you about the car

VIN (Vehicle Identification Number) is a car’s “passport” — a unique 17-character code the manufacturer uses to encode everything: country, plant, model, year, engine type, serial number. Knowing the VIN, you can check history, order the right parts, and even spot whether a used-car seller is passing a pre-facelift as a post-facelift. This post covers how to read the VIN via OBD-II and what each group of characters tells you.

VIN format — 17 characters in three groups

ISO 3779 (since 1981) splits VIN into three sections:

Positions	Group	What it identifies
1-3	WMI (World Manufacturer Identifier)	Country + manufacturer + producer type
4-9	VDS (Vehicle Descriptor Section)	Model, body, engine, trim
10-17	VIS (Vehicle Identifier Section)	Year, plant, serial number

VIN characters — any letters and digits except I, O, Q (to avoid confusion with 1 and 0). In Europe and Asia length is always 17. In the US pre-1981 VINs were shorter (up to 13 chars).

WMI (positions 1-3) — country and manufacturer

First character defines the region:

Letter/Digit	Region
A-H	Africa
J-R	Asia (Japan, Korea, India)
S-Z	Europe
1-5	North America
6-7	Oceania
8-9	South America

Second character — specific country (W — Germany, V — Spain / France, Y — Sweden / Belgium, Z — Italy, 1 — USA, J — Japan, etc.).

Third — manufacturer within that country (WBA — BMW, VF3 — Peugeot, 1FA — Ford USA, JT — Toyota, KMH — Hyundai, WVW — Volkswagen).

Example: WVWZZZ1KZ9W123456 → WVW = Volkswagen Passenger Cars, Germany.

VDS (positions 4-9) — model and trim

VDS is encoded by each manufacturer freely, but with common patterns. For most cars positions 4-8 describe:

• Body type (sedan, wagon, hatchback)
• Engine (displacement, fuel, power)
• Trim level (base, comfort, premium)
• Safety system (ABS, airbags)

Position 9 is the check digit. Computed by a strict formula from the other VIN characters. If the check digit doesn’t match — the VIN is forged or corrupted. Mechanics and customs check the check digit first.

Check Digit formula (simplified):

• Each character maps to a number (0-9 = itself, A=1, B=2, …, up to Z=8)
• Each position has a weight (8, 7, 6, 5, 4, 3, 2, 10, 0, 9, 8, 7, 6, 5, 4, 3, 2)
• Sum of (char × weight) is divided by 11, the remainder is the check digit (10 written as X)

Online VIN decoders do this check automatically. If the result is “invalid check digit” — the VIN is almost certainly forged.

VIS (positions 10-17) — year, plant, serial number

Position 10 — model year — the most important field for a used-car buyer. Encoded as a letter or a digit:

Char	Year	Char	Year
Y	2000	L	2020
1	2001	M	2021
2	2002	N	2022
…	…	P	2023
9	2009	R	2024
A	2010	S	2025
B	2011	T	2026

The cycle repeats every 30 years (2040 will again be Y), so position 7 also matters:

• Position 7 is a letter → model year 2010-2039
• Position 7 is a digit → model year 1980-2009

Position 11 — plant code (for Toyota 0 = Tahara, 1 = Motomachi, etc.). Positions 12-17 — sequential serial number of the car at that plant.

How to read VIN via OBD-II

SAE J1979 defines Mode 09 InfoType 02 — “Read VIN”. The ECU returns VIN as 17 ASCII characters (in three ISO-TP frames).

Not every car returns VIN over OBD-II — mandatory only for US diesels from 2004 and US gasoline from 2005. In Europe support started with Euro 5 (2011). For older cars VIN is only on the body (plate under windshield, driver door jamb, under the hood).

In Car Diagnostics VIN is read automatically on first connect — the Vehicle screen shows:

• Decoded VIN (make, model, year, engine type)
• Original VIN string (17 characters)
• Country of assembly (where actually assembled)
• Check Digit status (valid / invalid)

Our decoder uses a proprietary WMI database (~800 manufacturers) + VDS tables for major brands (Toyota, VW Group, BMW, Ford, GM, Renault-Nissan-Mitsubishi). Accuracy — above 95% for cars from 2005 onward.

Why VIN matters when buying a used car

• Model year — seller says “2020”, position 10 shows 9 → car is a 2009
• Country of assembly — a “Euro-spec” car may actually be US-market (matters for parts, electronics, warranty)
• Engine type — VDS encodes not just displacement but the exact engine code (e.g. 1.4 TSI EA111 vs EA211 — different generations, different failure modes)
• Rebuilt or not — position 9 (check digit) instantly reveals a re-stamped plate
• Position 11 — plant code. If the body plate says “assembled in Germany” but VIN says “Mexico” — questions…

Try the VIN decoder in Car Diagnostics — pair an ELM327 adapter, open the Vehicle tab. VIN read is free on any tier, full trim decoding is on the paid tier of the app. Also worth checking DTC P0630 — “VIN not programmed” — that appears after ECU replacement with an incorrect VIN.