2021 Ford Mustang — MOT failures & pass rate
880 MOT tests on the 2021 Ford Mustang are in this dataset, and 89.4% of them passed. Against coupes & convertibles of a similar age (8.8% fail rate), the 2021 Mustang comes out 1.7pp worse. Failures cluster in tyres, lighting & signalling and brakes.
What the MOT record shows
No single area dominates — tyres (5.7%) and lighting & signalling (3.3%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are headlamp aim, individual direction indicators and wipers — headlamp aim alone was recorded 20 times.
Advisories point at the next bill rather than this one: tyres was flagged on 16.9% of tests without failing them.
The trend is improving — the fail rate fell from 20.2% in 2021 to 9.1% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 5.7% | 50 |
| 2 | Lighting & signalling | 3.3% | 29 |
| 3 | Brakes | 1.9% | 17 |
| 4 | Visibility | 1.8% | 16 |
| 5 | Suspension | 1.3% | 11 |
| 6 | Emissions & environmental | 0.9% | 8 |
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 | 20 |
| 2 | Individual direction indicators | 19 |
| 3 | Wipers | 12 |
| 4 | Rear fog lamp | 12 |
| 5 | Tread depth | 10 |
| 6 | Side repeaters | 9 |
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 | 16.9% | 149 |
| 2 | Other defects | 3.4% | 30 |
| 3 | Suspension | 3.4% | 30 |
| 4 | Brakes | 3.1% | 27 |
| 5 | Visibility | 2.7% | 24 |
| 6 | Lighting & signalling | 1.4% | 12 |
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 | 708 | 9.5% |
| 30-60k | 122 | 13.9% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 104 | 20.2% |
| 2024 | 374 | 9.1% |
| 2025 | 384 | 9.1% |
What to check before buying a 2021 Mustang
On a 2021 Mustang, tyres is what the MOT record says goes wrong most — it appeared in 5.7% of tests. Check these areas before you commit.
- Tyres (5.7% 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 (3.3% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (1.9% 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 2021 Ford Mustangs pass their MOT?
89.4% of the 880 2021 Ford Mustang MOT tests in this dataset passed — a 10.6% fail rate.
What is the most common MOT failure on a 2021 Ford Mustang?
Tyres, recorded in 5.7% of tests, followed by lighting & signalling (3.3%).
Does the 2021 Mustang get worse with mileage?
Its MOT fail rate rises from 9.5% in the 0-30k band to 13.9% in the 30-60k band.
Methodology & source. Based on 880 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.