Audi S4 MOT pass rate & common failures
The Audi S4 appears in 12,048 MOT tests spanning model years 1992–2025, and 86.8% of them passed. Against executive cars of a similar age (17.9% fail rate), the S4 comes out 4.7pp better. Its most common failure areas are tyres, suspension and lighting & signalling.
What the MOT record shows
No single area dominates — tyres (4.8%) and suspension (4.6%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are headlamp aim, pins and bushes and catalyst emissions — headlamp aim alone was recorded 340 times.
A 150k+ example is materially riskier than a 0-30k one: 21.3% versus 4.8%.
The diesel cars hold up better: 7.3% fail against 15.9% for petrol, a 8.5-point gap across 12,048 tests.
Tyres is the most common advisory, noted on 18.8% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 16.1% in 2021 to 12.0% in 2025, as the worst-kept examples leave the fleet.
How it compares
By model year
Every S4 model year with a usable sample. Years with their own detailed report are linked.
| Year | Tests | Pass rate | Fail rate | Most common failure |
|---|---|---|---|---|
| 1998 | 66 | 84.9% | 15.2% | Lighting & signalling |
| 1999 | 316 | 82.9% | 17.1% | Lighting & signalling |
| 2000 | 239 | 83.7% | 16.3% | Lighting & signalling |
| 2001 | 34 | 73.5% | 26.5% | Lighting & signalling |
| 2003 | 192 | 79.2% | 20.8% | Suspension |
| 2004 | 890 | 80.7% | 19.3% | Lighting & signalling |
| 2005 | 787 | 83.5% | 16.5% | Lighting & signalling |
| 2006 | 836 | 80.7% | 19.3% | Suspension |
| 2007 | 564 | 80.7% | 19.3% | Suspension |
| 2008 | 151 | 80.8% | 19.2% | Suspension |
| 2009 | 787 | 85.8% | 14.2% | Suspension |
| 2010 | 1,072 | 85.4% | 14.6% | Suspension |
| 2011 | 916 | 85.2% | 14.8% | Tyres |
| 2012 | 400 | 86.3% | 13.8% | Suspension |
| 2013 | 335 | 91.0% | 9.0% | Tyres |
| 2014 | 437 | 88.1% | 11.9% | Tyres |
| 2015 | 116 | 90.5% | 9.5% | Tyres |
| 2017 | 120 | 90.0% | 10.0% | Tyres |
| 2018 | 60 | 86.7% | 13.3% | Tyres |
| 2019 | 865 | 92.5% | 7.5% | Tyres |
| 2020 | 2,258 | 93.0% | 7.0% | Tyres |
| 2021 | 327 | 93.0% | 7.0% | Tyres |
| 2022 | 217 | 93.1% | 6.9% | Tyres |
| 2023 | 38 | 94.7% | 5.3% | Brakes |
Most common failures (all years)
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 4.8% | 582 |
| 2 | Suspension | 4.6% | 559 |
| 3 | Lighting & signalling | 4.4% | 535 |
| 4 | Emissions & environmental | 2.3% | 275 |
| 5 | Brakes | 2.0% | 244 |
| 6 | Body, structure & corrosion | 1.7% | 207 |
| 7 | Visibility | 1.5% | 184 |
| 8 | Seat belts & restraints | 0.8% | 92 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Headlamp aim | 340 |
| 2 | Pins and bushes | 248 |
| 3 | Catalyst emissions | 241 |
| 4 | Coil spring | 188 |
| 5 | Tread depth | 179 |
| 6 | Joints | 161 |
| 7 | Ball joint dust cover | 149 |
| 8 | Headlamp | 120 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Tyres | 18.8% | 2,269 |
| 2 | Suspension | 18.2% | 2,190 |
| 3 | Brakes | 14.3% | 1,718 |
| 4 | Emissions & environmental | 9.0% | 1,083 |
| 5 | Other defects | 6.2% | 746 |
| 6 | Body, structure & corrosion | 4.8% | 578 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 0-30k | 1,361 | 4.8% |
| 30-60k | 2,879 | 8.6% |
| 60-90k | 2,964 | 13.9% |
| 90-120k | 2,718 | 17.3% |
| 120-150k | 1,278 | 17.1% |
| 150k+ | 840 | 21.3% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 8,318 | 15.9% |
| Diesel | 3,730 | 7.3% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 1,785 | 16.1% |
| 2022 | 1,968 | 15.5% |
| 2023 | 2,648 | 12.6% |
| 2024 | 2,728 | 11.7% |
| 2025 | 2,919 | 12.0% |
What to check before buying a Audi S4
- Tyres (4.8% of tests): Usually a quick, known-cost fix, but check tread, age and uneven wear (which can hint at alignment or suspension issues). Typical repair: £50–£120 per tyre.
- Suspension (4.6% of tests): Worn drop links, bushes, springs or shocks — listen for knocks over bumps and check for uneven tyre wear. Typical repair: £150–£450 per corner.
- Lighting & signalling (4.4% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.
Frequently asked questions
What is the MOT pass rate for the Audi S4?
86.8% of the 12,048 Audi S4 MOT tests in this dataset passed, a 13.2% fail rate, across model years 1992–2025.
What does the Audi S4 most often fail its MOT on?
Tyres, recorded in 4.8% of tests, then suspension (4.6%).
How much does mileage affect S4 MOT results?
Fail rates run at 4.8% for cars in the 0-30k band and 21.3% for 150k+, a 16.5-point difference.
Is the diesel or petrol S4 more reliable at MOT time?
On MOT-testable defects the diesel fails 7.3% of the time against 15.9% for the petrol. This covers testable items only, not engine or gearbox reliability.
Methodology & source. Based on 12,048 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-27. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.