2018 Porsche 911 — MOT failures & pass rate
The 2018 Porsche 911 passed 95.3% of its 11,495 recorded MOT tests. That is 4.3 percentage points better than coupes & convertibles of a similar age, which fail at 9.0%. Failures cluster in tyres, lighting & signalling and other defects.
What the MOT record shows
No single area dominates — tyres (3.0%) and lighting & signalling (1.1%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are registration plates, headlamp aim and tread depth — registration plates alone was recorded 154 times.
Mileage is the strongest signal on the record: 4.2% of 0-30k cars fail, rising to 13.0% once past 60-90k — 3.1× the risk.
Tyres is the most common advisory, noted on 11.1% of tests — work that passed today but is likely due soon.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 3.0% | 346 |
| 2 | Lighting & signalling | 1.1% | 126 |
| 3 | Other defects | 1.0% | 112 |
| 4 | Visibility | 0.5% | 62 |
| 5 | Emissions & environmental | 0.3% | 31 |
| 6 | Suspension | 0.3% | 29 |
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 | 154 |
| 2 | Headlamp aim | 132 |
| 3 | Tread depth | 98 |
| 4 | Washers | 50 |
| 5 | Catalyst emissions | 31 |
| 6 | Tyre pressure monitoring system | 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 | 11.1% | 1,279 |
| 2 | Other defects | 2.5% | 293 |
| 3 | Brakes | 1.5% | 167 |
| 4 | Visibility | 1.3% | 149 |
| 5 | Suspension | 0.5% | 56 |
| 6 | Emissions & environmental | 0.3% | 36 |
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 | 10,143 | 4.2% |
| 30-60k | 1,220 | 8.0% |
| 60-90k | 100 | 13.0% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 2,477 | 4.8% |
| 2022 | 2,392 | 4.5% |
| 2023 | 2,313 | 5.1% |
| 2024 | 2,127 | 4.8% |
| 2025 | 2,186 | 4.4% |
What to check before buying a 2018 911
The failure pattern for this year is specific enough to inspect against: tyres accounted for 3.0% of tests. Start there.
- Tyres (3.0% 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 (1.1% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Other defects (1.0% 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 2018 Porsche 911s pass their MOT?
95.3% of the 11,495 2018 Porsche 911 MOT tests in this dataset passed — a 4.7% fail rate.
What is the most common MOT failure on a 2018 Porsche 911?
Tyres, recorded in 3.0% of tests, followed by lighting & signalling (1.1%).
Does the 2018 911 get worse with mileage?
Its MOT fail rate rises from 4.2% in the 0-30k band to 13.0% in the 60-90k band.
Methodology & source. Based on 11,495 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.