1993 Porsche 911 — MOT failures & pass rate
The 1993 Porsche 911 passed 89.1% of its 1,351 recorded MOT tests. Coupes & convertibles of a similar age fail 19.3% of the time, so this is 8.4pp better than the group it competes with. Failures cluster in lighting & signalling, emissions & environmental and suspension.
What the MOT record shows
No single area dominates — lighting & signalling (7.3%) and emissions & environmental (4.8%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are catalyst emissions, headlamp aim and position lamp — catalyst emissions alone was recorded 99 times.
Condition tracks the odometer closely. Failures run at 13.3% in the 0-30k band and 19.3% in the 150k+ band, a 5.9-point spread.
Advisories point at the next bill rather than this one: emissions & environmental was flagged on 11.8% of tests without failing them.
The trend is improving — the fail rate fell from 12.1% in 2021 to 9.6% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 7.3% | 99 |
| 2 | Emissions & environmental | 4.8% | 65 |
| 3 | Suspension | 1.8% | 25 |
| 4 | Body, structure & corrosion | 1.5% | 20 |
| 5 | Brakes | 1.4% | 19 |
| 6 | Visibility | 1.2% | 16 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Catalyst emissions | 99 |
| 2 | Headlamp aim | 76 |
| 3 | Position lamp | 29 |
| 4 | Rear fog lamp | 24 |
| 5 | Stop lamp | 19 |
| 6 | Headlamp | 13 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Emissions & environmental | 11.8% | 159 |
| 2 | Suspension | 5.9% | 79 |
| 3 | Tyres | 5.8% | 78 |
| 4 | Brakes | 5.5% | 74 |
| 5 | Other defects | 3.5% | 47 |
| 6 | Visibility | 1.8% | 25 |
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 | 105 | 13.3% |
| 30-60k | 177 | 8.5% |
| 60-90k | 363 | 7.2% |
| 90-120k | 458 | 13.1% |
| 120-150k | 165 | 9.7% |
| 150k+ | 83 | 19.3% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 248 | 12.1% |
| 2022 | 289 | 12.5% |
| 2023 | 284 | 11.6% |
| 2024 | 259 | 8.5% |
| 2025 | 271 | 9.6% |
What to check before buying a 1993 911
On a 1993 911, lighting & signalling is what the MOT record says goes wrong most — it appeared in 7.3% of tests. Check these areas before you commit.
- Lighting & signalling (7.3% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Emissions & environmental (4.8% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
- Suspension (1.8% of tests): Worn drop links, bushes, springs or shocks — listen for knocks over bumps and check for uneven tyre wear. Typical repair: £150–£450 per corner.
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 1993 Porsche 911s pass their MOT?
89.1% of the 1,351 1993 Porsche 911 MOT tests in this dataset passed — a 10.9% fail rate.
What is the most common MOT failure on a 1993 Porsche 911?
Lighting & signalling, recorded in 7.3% of tests, followed by emissions & environmental (4.8%).
Does the 1993 911 get worse with mileage?
Its MOT fail rate rises from 13.3% in the 0-30k band to 19.3% in the 150k+ band.
Methodology & source. Based on 1,351 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.