2021 Audi A4 S Ln Black Ed 35Tdi Mhev Sa — MOT failures & pass rate
Across 1,542 MOT tests analysed for the 2021 Audi A4 S Ln Black Ed 35Tdi Mhev Sa, the most common recorded failure areas were tyres, emissions & environmental and visibility. Its pass rate of 88.5% was below the average for cars of a similar age (91.2%).
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 8.7% | 134 |
| 2 | Emissions & environmental | 1.8% | 28 |
| 3 | Visibility | 1.2% | 18 |
| 4 | Lighting & signalling | 1.1% | 17 |
| 5 | Brakes | 1.0% | 16 |
| 6 | Other defects | 0.5% | 8 |
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 | 63 |
| 2 | Malfunction indicator lamp | 28 |
| 3 | Brake pads | 18 |
| 4 | Headlamp aim | 16 |
| 5 | Registration plates | 15 |
| 6 | Washers | 10 |
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 | 22.8% | 351 |
| 2 | Brakes | 10.8% | 166 |
| 3 | Other defects | 6.6% | 102 |
| 4 | Suspension | 4.0% | 61 |
| 5 | Visibility | 3.5% | 54 |
| 6 | Emissions & environmental | 0.8% | 13 |
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 | 425 | 9.7% |
| 30-60k | 906 | 11.6% |
| 60-90k | 178 | 14.0% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2023 | 31 | 0.0% |
| 2024 | 779 | 11.0% |
| 2025 | 732 | 12.4% |
What to check before buying a 2021 A4 S Ln Black Ed 35Tdi Mhev Sa
Before buying a 2021 Audi A4 S Ln Black Ed 35Tdi Mhev Sa, focus on the areas it most often fails on. Tyres accounted for 8.7% of tests for this year.
- Tyres (8.7% 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.
- Emissions & environmental (1.8% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
- Visibility (1.2% of tests): Wipers, washers, mirrors and screen damage — usually inexpensive, but check for chips in the driver's line of sight. Typical repair: £15–£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 A4 S Ln Black Ed 35Tdi Mhev Sas pass their MOT?
88.5% of the 1,542 2021 Audi A4 S Ln Black Ed 35Tdi Mhev Sa MOT tests in this dataset passed — a 11.5% fail rate.
What is the most common MOT failure on a 2021 Audi A4 S Ln Black Ed 35Tdi Mhev Sa?
Tyres, recorded in 8.7% of tests, followed by emissions & environmental (1.8%).
Does the 2021 A4 S Ln Black Ed 35Tdi Mhev Sa get worse with mileage?
Its MOT fail rate rises from 9.7% in the 0-30k band to 14.0% in the 60-90k band.
Methodology & source. Based on 1,542 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.