A Audi S4 VIN is 17 characters. Positions 1–3 say who built it and where, 4–8 describe the body and engine, 9 is a check digit, 10 is the model year, 11 is the plant, and 12–17 are the serial number. Decode a S4 VIN here and you also get its 36 recall campaigns and 468 owner complaints filed with NHTSA — free.
How to read a Audi S4 VIN
Here is a real 2021 Audi S4 VIN from our database, split into its parts:
VIN WAUB4AF46MA039900 — decoded free on its own report page.
| Position | Section | What it tells you |
|---|---|---|
| 1–3 | WMI | World Manufacturer Identifier — country, manufacturer and vehicle type. |
| 4–8 | VDS | Vehicle Descriptor Section — body style, engine, restraint system, series. |
| 9 | Check digit | A calculated digit that validates the whole VIN. Wrong digit = wrong VIN. |
| 10 | Model year | One character for the model year. Letters skip I, O, Q, U and Z. |
| 11 | Plant | The assembly plant that built the car. |
| 12–17 | Serial | Sequential production number of this exact vehicle. |
Audi S4 VIN prefixes, and when each one was used
Characters 1–3 are not fixed for the life of a model. The Audi S4 ran through 2 different prefixes across 17 years — a S4 built in 1992 opens with WAU, one from 2008 with WUA, and a chart that assumes S4 always starts the same way will hand you the wrong car:
| VIN starts with | Years seen | Built in | Vehicle type | VINs on record |
|---|---|---|---|---|
| WAU | 1992–2021 | Germany | Passenger Car | |
| WUA | 2004–2008 | Germany | Passenger Car |
Position 11 names the plant. On the Audi S4 it is not one number either — assembly moved between 3 of them over the years:
| Plant code | Years active | VINs on record | Share |
|---|---|---|---|
| A | 2000–2021 | 433 | |
| N | 1992–1994 | 23 | |
| K | 2004–2008 | 11 |
Counted from the 467 dated Audi S4 VINs attached to NHTSA complaints — the largest such set for this model — with every code checked against the NHTSA manufacturer registry, so mistyped entries are dropped; the figures say how many records carry each code, not how many S4s left the line.
Model-year codes for the Audi S4
Position 10 carries the model year, skipping I, O, Q, U and Z. The alphabet comes round every 30 years, which for the Audi S4 has already happened — 1994 and 2024 share the character R. All 28 model years of the Audi S4, 1992 to 2026, with the character each one carries:
| Model year | VIN character (position 10) | Same character as |
|---|---|---|
| 2026 | T | — |
| 2025 | S | — |
| 2024 | R | 1994 |
| 2023 | P | 1993 |
| 2022 | N | 1992 |
| 2021 | M | — |
| 2020 | L | — |
| 2019 | K | — |
| 2018 | J | — |
| 2016 | G | — |
| 2015 | F | — |
| 2014 | E | — |
| 2013 | D | — |
| 2012 | C | — |
| 2011 | B | — |
| 2010 | A | — |
| 2009 | 9 | — |
| 2008 | 8 | — |
| 2007 | 7 | — |
| 2006 | 6 | — |
| 2005 | 5 | — |
| 2004 | 4 | — |
| 2002 | 2 | — |
| 2001 | 1 | — |
| 2000 | Y | — |
| 1994 | R | 2024 |
| 1993 | P | 2023 |
| 1992 | N | 2022 |
When two years share a character, the check digit and serial range tell them apart — that is what the decoder does automatically.
Body and engine characters we see on Audi S4 VINs
Positions 4 through 8 describe the build, and manufacturers assign them themselves — the same letter means different things on different marques. Across 32 VINs the Audi S4 uses 16 different characters in these three slots alone — the ones below, ordered by how much of the Audi fleet each covers:
| Position | Characters seen on real VINs | Variety |
|---|---|---|
| 4 — body | B (53%) · C (13%) · D (9%) · F (9%) · G (3%) · H (3%) | 6 distinct |
| 5 — series | 4 (53%) · G (38%) · L (3%) · P (3%) · D (3%) | 5 distinct |
| 8 — engine | 4 (53%) · L (38%) · E (3%) · A (3%) · D (3%) | 5 distinct |
A character that dominates the column usually marks the body style the model was mostly sold in; a spread across several means multiple bodies or engines shared the same platform.
What a decoded Audi S4 VIN gets you
Reading the characters is the easy part — the reason to decode a VIN is what sits behind it. For the Audi S4 that is 468 owner complaints and every recall campaign NHTSA has on record, keyed to the same VIN you just read:
| Data | For this model | Source |
|---|---|---|
| Recall campaigns | 36 campaigns | NHTSA |
| Owner complaints | 468 filed | NHTSA |
| Fuel economy | 20 mpg combined (avg) | EPA |
| Crash-test ratings | 6 rated model years | NHTSA |
| Model years covered | 28 years | ForCar catalog |
Where to find the VIN on a Audi S4
A Audi S4 VIN normally opens with WAU. Four places on the car carry the full number, and all four must agree — on a Audi S4, a plate that disagrees is where fraud shows itself first.
| Where | How to see it | Why it matters |
|---|---|---|
| Dashboard, driver side | Through the windshield, bottom corner | Easiest to check before you touch anything |
| Driver door jamb | Open the door, sticker on the pillar | Also lists tyre pressures and build date |
| Under the hood | Firewall or strut tower plate | Survives a windshield replacement |
| Title and insurance | Paper documents | Must match the car — a mismatch means fraud or a swapped panel |
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Frequently asked questions
Is this Audi S4 VIN decoder free?
Yes — decoding a Audi S4 VIN costs nothing and needs no account. Beyond the year, plant and build characters you also get what NHTSA holds on the Audi S4 — 36 recall campaigns and 468 owner complaints — at no charge.
Why does my S4 VIN start differently from another S4?
Because the prefix changed during the model's run. Across the Audi S4 VINs on record we see 2 of them: WAU (1992–2021), WUA (2004–2008). A 1992 car opens with WAU, a 2008 one with WUA, and both are genuine. A decoder that assumes a single prefix for the whole model is where the wrong answers come from.
How many characters is a Audi S4 VIN?
Seventeen, on every Audi S4 built from 1981 onwards, when the 17-character format became mandatory in the US. The oldest Audi S4 VIN on file here is a 1992, so everything in our Audi data already uses the modern layout.
Why do two Audi S4 model years share the same VIN character?
Position 10 cycles through the alphabet every 30 years, skipping I, O, Q, U and Z. For the Audi S4 that is not theoretical: a 1994 and a 2024 both carry R in position 10, and this model was built in both years. The check digit and serial range separate them.
Can a Audi S4 VIN tell me if the car was in an accident?
Not from the characters themselves — they describe how the Audi S4 left the factory, not what happened to it afterwards. Crash and title records sit in separate databases keyed to the same number. What is public are the 468 complaints Audi S4 owners filed with NHTSA, and those we do show. Run the number through our VIN check to see what is on the record for it.
Do the body and engine characters mean the same thing on every Audi?
No, and that is the usual mistake — positions 4–8 are assigned per model, not per brand. A letter that means one body on the Audi S4 can mean a different one on another Audi, and something else again on another marque. On Audi S4 VINs the character that dominates position 4 is B — read it against the table above, not against a generic chart.
What if the VIN on the dashboard doesn't match the door jamb?
Treat it as a red flag on any car, and on a Audi S4 check the prefix first: for the model year in question it should open with WAU or WUA, depending on when the car was built — anything outside that set did not come off a Audi S4. Beyond that, mismatched plates mean either a replaced panel or a tampered identity — ask for documents and verify before any money changes hands.
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