2021 Audi A5 S Line 35 Mhev S-A — MOT failures & pass rate
Across 3,980 MOT tests analysed for the 2021 Audi A5 S Line 35 Mhev S-A, the most common recorded failure areas were tyres, lighting & signalling and emissions & environmental. Its pass rate of 90.7% was in line with the average for cars of a similar age (91.2%). Higher-mileage examples failed more often — 13.5% in the 60-90k group versus 8.5% in the 0-30k group.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 5.6% | 223 |
| 2 | Lighting & signalling | 2.2% | 86 |
| 3 | Emissions & environmental | 2.0% | 81 |
| 4 | Brakes | 1.1% | 42 |
| 5 | Visibility | 1.1% | 42 |
| 6 | Suspension | 0.5% | 22 |
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 | 142 |
| 2 | Headlamp aim | 103 |
| 3 | Malfunction indicator lamp | 81 |
| 4 | Brake pads | 33 |
| 5 | Registration plates | 28 |
| 6 | Shock absorbers | 26 |
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 | 23.1% | 919 |
| 2 | Brakes | 9.7% | 385 |
| 3 | Other defects | 7.0% | 280 |
| 4 | Suspension | 3.2% | 129 |
| 5 | Visibility | 2.7% | 109 |
| 6 | Road wheels | 0.4% | 16 |
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 | 1,678 | 8.5% |
| 30-60k | 2,038 | 9.5% |
| 60-90k | 237 | 13.5% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 2,958 | 10.0% |
| Petrol | 1,010 | 7.2% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2023 | 55 | 3.6% |
| 2024 | 2,036 | 8.9% |
| 2025 | 1,888 | 9.9% |
What to check before buying a 2021 A5 S Line 35 Mhev S-A
Before buying a 2021 Audi A5 S Line 35 Mhev S-A, focus on the areas it most often fails on. Tyres accounted for 5.6% of tests for this year.
- Tyres (5.6% 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 (2.2% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Emissions & environmental (2.0% 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 2021 Audi A5 S Line 35 Mhev S-As pass their MOT?
90.7% of the 3,980 2021 Audi A5 S Line 35 Mhev S-A MOT tests in this dataset passed — a 9.3% fail rate.
What is the most common MOT failure on a 2021 Audi A5 S Line 35 Mhev S-A?
Tyres, recorded in 5.6% of tests, followed by lighting & signalling (2.2%).
Does the 2021 A5 S Line 35 Mhev S-A get worse with mileage?
Its MOT fail rate rises from 8.5% in the 0-30k band to 13.5% in the 60-90k band.
Methodology & source. Based on 3,980 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-01. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.