1999 Porsche Boxster — MOT failures & pass rate
Across 6,482 MOT tests, the 1999 Porsche Boxster recorded a 79.1% pass rate. Coupes & convertibles of a similar age fail 22.0% of the time, so this is 1.1pp better than the group it competes with. Failures cluster in lighting & signalling, emissions & environmental and brakes.
What the MOT record shows
No single area dominates — lighting & signalling (10.3%) and emissions & environmental (9.0%) 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 rigid brake pipes — catalyst emissions alone was recorded 679 times.
A 150k+ example is materially riskier than a 0-30k one: 31.0% versus 10.4%.
Advisories point at the next bill rather than this one: brakes was flagged on 30.2% of tests without failing them.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 10.3% | 665 |
| 2 | Emissions & environmental | 9.0% | 581 |
| 3 | Brakes | 5.9% | 384 |
| 4 | Suspension | 5.3% | 340 |
| 5 | Tyres | 3.1% | 203 |
| 6 | Visibility | 3.0% | 197 |
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 | 679 |
| 2 | Headlamp aim | 339 |
| 3 | Rigid brake pipes | 264 |
| 4 | Headlamp | 206 |
| 5 | Position lamp | 176 |
| 6 | Tread depth | 140 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Brakes | 30.2% | 1,960 |
| 2 | Suspension | 21.0% | 1,363 |
| 3 | Tyres | 19.6% | 1,273 |
| 4 | Emissions & environmental | 13.3% | 861 |
| 5 | Lighting & signalling | 8.7% | 564 |
| 6 | Body, structure & corrosion | 6.2% | 403 |
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 | 183 | 10.4% |
| 30-60k | 816 | 13.7% |
| 60-90k | 2,003 | 17.4% |
| 90-120k | 2,181 | 23.2% |
| 120-150k | 898 | 26.8% |
| 150k+ | 361 | 31.0% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 1,383 | 22.0% |
| 2022 | 1,383 | 20.7% |
| 2023 | 1,290 | 20.3% |
| 2024 | 1,225 | 20.2% |
| 2025 | 1,201 | 21.2% |
What to check before buying a 1999 Boxster
On a 1999 Boxster, lighting & signalling is what the MOT record says goes wrong most — it appeared in 10.3% of tests. Check these areas before you commit.
- Lighting & signalling (10.3% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Emissions & environmental (9.0% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
- Brakes (5.9% of tests): Pads/discs are routine wear; binding, imbalance or corroded pipes are more serious — test for pulling under braking. Typical repair: £100–£350 per axle.
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 1999 Porsche Boxsters pass their MOT?
79.1% of the 6,482 1999 Porsche Boxster MOT tests in this dataset passed — a 20.9% fail rate.
What is the most common MOT failure on a 1999 Porsche Boxster?
Lighting & signalling, recorded in 10.3% of tests, followed by emissions & environmental (9.0%).
Does the 1999 Boxster get worse with mileage?
Its MOT fail rate rises from 10.4% in the 0-30k band to 31.0% in the 150k+ band.
Methodology & source. Based on 6,482 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.