2021 Porsche 911 Turbo S S-A — MOT failures & pass rate
Across 599 MOT tests analysed for the 2021 Porsche 911 Turbo S S-A, the most common recorded failure areas were tyres, emissions & environmental and other defects. Its pass rate of 96.7% was above the average for cars of a similar age (91.2%).
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 1.8% | 11 |
| 2 | Emissions & environmental | 0.8% | 5 |
| 3 | Other defects | 0.7% | 4 |
| 4 | Brakes | 0.2% | 1 |
| 5 | Visibility | 0.2% | 1 |
| 6 | Suspension | 0.2% | 1 |
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 | 6 |
| 2 | Tread depth | 6 |
| 3 | Malfunction indicator lamp | 2 |
| 4 | Catalyst emissions | 2 |
| 5 | Shock absorbers | 1 |
| 6 | Washers | 1 |
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 | 8.7% | 52 |
| 2 | Other defects | 2.7% | 16 |
| 3 | Suspension | 0.5% | 3 |
| 4 | Visibility | 0.5% | 3 |
| 5 | Brakes | 0.2% | 1 |
| 6 | Emissions & environmental | 0.2% | 1 |
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 | 578 | 2.9% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2024 | 284 | 4.6% |
| 2025 | 306 | 2.3% |
What to check before buying a 2021 911 Turbo S S-A
Before buying a 2021 Porsche 911 Turbo S S-A, focus on the areas it most often fails on. Tyres accounted for 1.8% of tests for this year.
- Tyres (1.8% 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.
- Emissions & environmental (0.8% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
- Other defects (0.7% of tests): Miscellaneous items not in the main categories. Typical repair: varies.
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 Porsche 911 Turbo S S-As pass their MOT?
96.7% of the 599 2021 Porsche 911 Turbo S S-A MOT tests in this dataset passed — a 3.3% fail rate.
What is the most common MOT failure on a 2021 Porsche 911 Turbo S S-A?
Tyres, recorded in 1.8% of tests, followed by emissions & environmental (0.8%).
Methodology & source. Based on 599 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.