2021 Mazda CX-30 — MOT failures & pass rate
Across 16,971 MOT tests, the 2021 Mazda CX-30 recorded a 94.5% pass rate. Small SUVs of a similar age fail 7.2% of the time, so this is 1.7pp better than the group it competes with. Failures cluster in tyres, visibility and brakes.
What the MOT record shows
No single area dominates — tyres (2.9%) and visibility (1.9%) 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 wipers — tread depth alone was recorded 243 times.
A 60-90k example is materially riskier than a 0-30k one: 10.7% versus 4.1%.
Advisories point at the next bill rather than this one: brakes was flagged on 19.5% of tests without failing them.
The trend is worsening — 2.3% of tests failed in 2023 against 5.8% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 2.9% | 484 |
| 2 | Visibility | 1.9% | 326 |
| 3 | Brakes | 1.6% | 273 |
| 4 | Lighting & signalling | 1.1% | 185 |
| 5 | Emissions & environmental | 0.5% | 85 |
| 6 | Suspension | 0.4% | 73 |
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 | 243 |
| 2 | Brake pads | 223 |
| 3 | Wipers | 212 |
| 4 | Headlamp aim | 209 |
| 5 | Washers | 166 |
| 6 | Shock absorbers | 90 |
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 | 19.5% | 3,307 |
| 2 | Tyres | 18.0% | 3,061 |
| 3 | Suspension | 8.5% | 1,448 |
| 4 | Other defects | 4.7% | 797 |
| 5 | Visibility | 2.4% | 408 |
| 6 | Lighting & signalling | 0.2% | 38 |
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 | 11,413 | 4.1% |
| 30-60k | 5,263 | 8.2% |
| 60-90k | 272 | 10.7% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 16,765 | 5.5% |
| Hybrid | 204 | 2.9% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2023 | 172 | 2.3% |
| 2024 | 8,347 | 5.3% |
| 2025 | 8,446 | 5.8% |
What to check before buying a 2021 CX-30
On a 2021 CX-30, tyres is what the MOT record says goes wrong most — it appeared in 2.9% of tests. Check these areas before you commit.
- Tyres (2.9% 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.
- Visibility (1.9% 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 (1.6% 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 2021 Mazda CX-30s pass their MOT?
94.5% of the 16,971 2021 Mazda CX-30 MOT tests in this dataset passed — a 5.5% fail rate.
What is the most common MOT failure on a 2021 Mazda CX-30?
Tyres, recorded in 2.9% of tests, followed by visibility (1.9%).
Does the 2021 CX-30 get worse with mileage?
Its MOT fail rate rises from 4.1% in the 0-30k band to 10.7% in the 60-90k band.
Methodology & source. Based on 16,971 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.