2021 Mazda 3 — MOT failures & pass rate
8,377 MOT tests on the 2021 Mazda 3 are in this dataset, and 93.0% of them passed. Against small family cars of a similar age (8.3% fail rate), the 2021 3 comes out 1.4pp better. Failures cluster in tyres, visibility and lighting & signalling.
What the MOT record shows
No single area dominates — tyres (4.6%) and visibility (2.3%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are headlamp aim, wipers and washers — headlamp aim alone was recorded 214 times.
A 60-90k example is materially riskier than a 0-30k one: 13.0% versus 5.6%.
Advisories point at the next bill rather than this one: tyres was flagged on 20.8% of tests without failing them.
The trend is worsening — 3.7% of tests failed in 2023 against 7.2% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 4.6% | 387 |
| 2 | Visibility | 2.3% | 196 |
| 3 | Lighting & signalling | 2.0% | 170 |
| 4 | Brakes | 1.4% | 115 |
| 5 | Emissions & environmental | 0.4% | 37 |
| 6 | Suspension | 0.3% | 24 |
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 | 214 |
| 2 | Wipers | 129 |
| 3 | Washers | 104 |
| 4 | Brake pads | 90 |
| 5 | Tread depth | 53 |
| 6 | Malfunction indicator lamp | 34 |
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 | 20.8% | 1,746 |
| 2 | Brakes | 14.7% | 1,233 |
| 3 | Other defects | 4.3% | 356 |
| 4 | Visibility | 2.3% | 194 |
| 5 | Road wheels | 1.7% | 141 |
| 6 | Suspension | 0.5% | 39 |
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 | 5,489 | 5.6% |
| 30-60k | 2,604 | 9.3% |
| 60-90k | 253 | 13.0% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2023 | 108 | 3.7% |
| 2024 | 4,113 | 6.7% |
| 2025 | 4,133 | 7.2% |
What to check before buying a 2021 3
On a 2021 3, tyres is what the MOT record says goes wrong most — it appeared in 4.6% of tests. Check these areas before you commit.
- Tyres (4.6% 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 (2.3% 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.
- 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.
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 3s pass their MOT?
93.0% of the 8,377 2021 Mazda 3 MOT tests in this dataset passed — a 7.0% fail rate.
What is the most common MOT failure on a 2021 Mazda 3?
Tyres, recorded in 4.6% of tests, followed by visibility (2.3%).
Does the 2021 3 get worse with mileage?
Its MOT fail rate rises from 5.6% in the 0-30k band to 13.0% in the 60-90k band.
Methodology & source. Based on 8,377 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.