2020 Audi S4 — MOT failures & pass rate
The 2020 Audi S4 passed 93.0% of its 2,258 recorded MOT tests. Against executive cars of a similar age (10.0% fail rate), the 2020 S4 comes out 2.9pp better. Failures cluster in tyres, lighting & signalling and emissions & environmental.
What the MOT record shows
One area stands out: tyres, recorded in 4.7% of tests against 0.9% for the next-worst category.
At component level the recurring items are tread depth, headlamp aim and brake pads — tread depth alone was recorded 32 times.
A 90-120k example is materially riskier than a 0-30k one: 18.9% versus 4.2%.
Tyres is the most common advisory, noted on 17.3% of tests — work that passed today but is likely due soon.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 4.7% | 106 |
| 2 | Lighting & signalling | 0.9% | 20 |
| 3 | Emissions & environmental | 0.7% | 15 |
| 4 | Visibility | 0.6% | 14 |
| 5 | Suspension | 0.6% | 13 |
| 6 | Brakes | 0.6% | 13 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Tread depth | 32 |
| 2 | Headlamp aim | 25 |
| 3 | Brake pads | 16 |
| 4 | Malfunction indicator lamp | 13 |
| 5 | Registration plates | 12 |
| 6 | Wipers | 9 |
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 | 17.3% | 391 |
| 2 | Brakes | 9.9% | 223 |
| 3 | Other defects | 5.3% | 120 |
| 4 | Suspension | 5.2% | 117 |
| 5 | Visibility | 2.9% | 65 |
| 6 | Steering | 0.2% | 4 |
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 | 674 | 4.2% |
| 30-60k | 1,256 | 7.9% |
| 60-90k | 288 | 8.7% |
| 90-120k | 37 | 18.9% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2022 | 36 | 8.3% |
| 2023 | 750 | 6.8% |
| 2024 | 725 | 6.3% |
| 2025 | 744 | 7.9% |
What to check before buying a 2020 S4
The failure pattern for this year is specific enough to inspect against: tyres accounted for 4.7% of tests. Start there.
- Tyres (4.7% 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.
- Lighting & signalling (0.9% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Emissions & environmental (0.7% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.
Frequently asked questions
How many 2020 Audi S4s pass their MOT?
93.0% of the 2,258 2020 Audi S4 MOT tests in this dataset passed — a 7.0% fail rate.
What is the most common MOT failure on a 2020 Audi S4?
Tyres, recorded in 4.7% of tests, followed by lighting & signalling (0.9%).
Does the 2020 S4 get worse with mileage?
Its MOT fail rate rises from 4.2% in the 0-30k band to 18.9% in the 90-120k band.
Methodology & source. Based on 2,258 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.