2021 Audi RS4 — MOT failures & pass rate
Across 671 MOT tests, the 2021 Audi RS4 recorded a 92.1% pass rate. Against executive cars of a similar age (9.8% fail rate), the 2021 RS4 comes out 1.9pp better. Failures cluster in tyres, other defects and lighting & signalling.
What the MOT record shows
Tyres dominates the failure mix at 4.9% of all tests — 3.9 points clear of other defects, so it is the first thing to check.
At component level the recurring items are registration plates, headlamp aim and tread depth — registration plates alone was recorded 12 times.
Advisories point at the next bill rather than this one: tyres was flagged on 15.2% of tests without failing them.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 4.9% | 33 |
| 2 | Other defects | 1.0% | 7 |
| 3 | Lighting & signalling | 0.9% | 6 |
| 4 | Brakes | 0.9% | 6 |
| 5 | Body, structure & corrosion | 0.6% | 4 |
| 6 | Emissions & environmental | 0.3% | 2 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Registration plates | 12 |
| 2 | Headlamp aim | 5 |
| 3 | Tread depth | 5 |
| 4 | Brake pads | 4 |
| 5 | Washers | 2 |
| 6 | Attachment | 2 |
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 | 15.2% | 102 |
| 2 | Other defects | 7.3% | 49 |
| 3 | Brakes | 7.0% | 47 |
| 4 | Suspension | 4.0% | 27 |
| 5 | Visibility | 2.5% | 17 |
| 6 | Road wheels | 0.4% | 3 |
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 | 373 | 6.4% |
| 30-60k | 268 | 9.3% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2024 | 314 | 8.9% |
| 2025 | 346 | 7.2% |
What to check before buying a 2021 RS4
On a 2021 RS4, tyres is what the MOT record says goes wrong most — it appeared in 4.9% of tests. Check these areas before you commit.
- Tyres (4.9% 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.
- Other defects (1.0% of tests): Miscellaneous items not in the main categories. Typical repair: varies.
- 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.
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 2021 Audi RS4s pass their MOT?
92.1% of the 671 2021 Audi RS4 MOT tests in this dataset passed — a 7.9% fail rate.
What is the most common MOT failure on a 2021 Audi RS4?
Tyres, recorded in 4.9% of tests, followed by other defects (1.0%).
Does the 2021 RS4 get worse with mileage?
Its MOT fail rate rises from 6.4% in the 0-30k band to 9.3% in the 30-60k band.
Methodology & source. Based on 671 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.