1990 Porsche 928 S — MOT failures & pass rate
263 MOT tests on the 1990 Porsche 928 S are in this dataset, and 82.9% of them passed. Against all cars of a similar age (21.8% fail rate), the 1990 928 S comes out 4.7pp better. Failures cluster in lighting & signalling, visibility and brakes.
What the MOT record shows
One area stands out: lighting & signalling, recorded in 11.4% of tests against 6.1% for the next-worst category.
At component level the recurring items are headlamp aim, washers and position lamp — headlamp aim alone was recorded 17 times.
Mileage matters less than usual here: the 1990 928 S fails 13.8% of the time in the 90-120k band and 13.9% at 150k+, a spread of only 0.1 points.
Emissions & environmental is the most common advisory, noted on 19.4% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 19.1% in 2021 to 9.3% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 11.4% | 30 |
| 2 | Visibility | 6.1% | 16 |
| 3 | Brakes | 4.6% | 12 |
| 4 | Body, structure & corrosion | 3.0% | 8 |
| 5 | Steering | 2.7% | 7 |
| 6 | Suspension | 2.3% | 6 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Headlamp aim | 17 |
| 2 | Washers | 15 |
| 3 | Position lamp | 14 |
| 4 | Flexible brake hoses | 10 |
| 5 | Rear fog lamp | 9 |
| 6 | Stop lamp | 6 |
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 | 19.4% | 51 |
| 2 | Brakes | 15.2% | 40 |
| 3 | Other defects | 14.8% | 39 |
| 4 | Tyres | 13.7% | 36 |
| 5 | Suspension | 11.4% | 30 |
| 6 | Lighting & signalling | 7.2% | 19 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 90-120k | 80 | 13.8% |
| 120-150k | 98 | 19.4% |
| 150k+ | 36 | 13.9% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 47 | 19.1% |
| 2022 | 61 | 19.7% |
| 2023 | 61 | 18.0% |
| 2024 | 51 | 17.6% |
| 2025 | 43 | 9.3% |
What to check before buying a 1990 928 S
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 11.4% of tests. Start there.
- Lighting & signalling (11.4% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Visibility (6.1% 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.
- Brakes (4.6% 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 1990 Porsche 928 Ss pass their MOT?
82.9% of the 263 1990 Porsche 928 S MOT tests in this dataset passed — a 17.1% fail rate.
What is the most common MOT failure on a 1990 Porsche 928 S?
Lighting & signalling, recorded in 11.4% of tests, followed by visibility (6.1%).
Does the 1990 928 S get worse with mileage?
Its MOT fail rate rises from 13.8% in the 90-120k band to 13.9% in the 150k+ band.
Methodology & source. Based on 263 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.