2018 Infiniti Q30 — MOT failures & pass rate
The 2018 Infiniti Q30 passed 91.8% of its 1,693 recorded MOT tests. That is 2.2 percentage points better than small family cars of a similar age, which fail at 10.4%. Failures cluster in tyres, lighting & signalling and visibility.
What the MOT record shows
No single area dominates — tyres (4.1%) and lighting & signalling (2.0%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are tread depth, brake pads and washers — tread depth alone was recorded 41 times.
A 90-120k example is materially riskier than a 0-30k one: 20.0% versus 5.4%.
Split by fuel, diesel examples fail 2.9pp more often than petrol ones (9.6% vs 6.7%) — worth weighing if you have a choice.
Advisories point at the next bill rather than this one: tyres was flagged on 23.2% of tests without failing them.
The trend is worsening — 5.7% of tests failed in 2021 against 10.6% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 4.1% | 69 |
| 2 | Lighting & signalling | 2.0% | 34 |
| 3 | Visibility | 2.0% | 34 |
| 4 | Brakes | 1.7% | 29 |
| 5 | Suspension | 0.9% | 16 |
| 6 | Emissions & environmental | 0.5% | 8 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Tread depth | 41 |
| 2 | Brake pads | 25 |
| 3 | Washers | 24 |
| 4 | Headlamp aim | 24 |
| 5 | Linkage ball joint dust cover | 14 |
| 6 | Wipers | 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 | Tyres | 23.2% | 392 |
| 2 | Brakes | 14.2% | 240 |
| 3 | Other defects | 5.3% | 89 |
| 4 | Visibility | 1.8% | 31 |
| 5 | Suspension | 1.7% | 29 |
| 6 | Lighting & signalling | 0.7% | 11 |
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 | 666 | 5.4% |
| 30-60k | 767 | 8.5% |
| 60-90k | 203 | 12.8% |
| 90-120k | 45 | 20.0% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 861 | 9.6% |
| Petrol | 832 | 6.7% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 334 | 5.7% |
| 2022 | 348 | 8.1% |
| 2023 | 344 | 9.0% |
| 2024 | 328 | 7.6% |
| 2025 | 339 | 10.6% |
What to check before buying a 2018 Q30
On a 2018 Q30, tyres is what the MOT record says goes wrong most — it appeared in 4.1% of tests. Check these areas before you commit.
- Tyres (4.1% 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 (2.0% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Visibility (2.0% 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.
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 Infiniti Q30s pass their MOT?
91.8% of the 1,693 2018 Infiniti Q30 MOT tests in this dataset passed — a 8.2% fail rate.
What is the most common MOT failure on a 2018 Infiniti Q30?
Tyres, recorded in 4.1% of tests, followed by lighting & signalling (2.0%).
Does the 2018 Q30 get worse with mileage?
Its MOT fail rate rises from 5.4% in the 0-30k band to 20.0% in the 90-120k band.
Methodology & source. Based on 1,693 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.