MOT fail rates
Smart Forfour MOT fail rate by age
How often the Smart Forfour fails its MOT at each age, compared with all cars of the same age, and what it fails on. From 89,645 DVSA MOT tests taken 2022 to 2025.
MOT data updated
At 7 years, the most tested age
240 of 330 model groups with enough tests fail less often at 7 years.
What stands out
- At 3 years the Smart Forfour fails 11.4% of MOTs (3,863 tests), about the same as the 12.1% for all cars that age. At 10 years it fails 33.8% (5,445 tests), 3.5 points above the 30.3% average.
- The gap is widest at 8 years: 3.6 points above all cars.
- Its most common structural or mechanical fail item at 7 years: Suspension ball joint worn, at 2.5 per 100 MOTs.
MOT fail rate by age, first used undefined or later
Solid line: this model. Dashed line: all cars at the same age.
| Age | MOT fail rate | Tests (n) | All cars | Difference | Median mileage |
|---|---|---|---|---|---|
| 3 years | 11.4% | 3,863 | 12.1% | −0.6 pts | 11,789 miles |
| 4 years | 16.1% | 7,076 | 13.4% | +2.7 pts | 17,649 miles |
| 5 years | 17.8% | 11,275 | 15.3% | +2.5 pts | 24,312 miles |
| 6 years | 20.7% | 15,976 | 17.8% | +2.9 pts | 30,677 miles |
| 7 years | 24.0% | 19,511 | 20.6% | +3.4 pts | 36,660 miles |
| 8 years | 27.4% | 15,678 | 23.8% | +3.6 pts | 42,334 miles |
| 9 years | 30.7% | 10,821 | 27.1% | +3.6 pts | 47,376 miles |
| 10 years | 33.8% | 5,445 | 30.3% | +3.5 pts | 52,999 miles |
Most common fail items at 7 years
Split into structural or mechanical items and wear items. Wear items (tyres, brake pads, wipers, bulbs) say more about upkeep than about the design.
Structural and mechanical
| Fail item | Per 100 MOTs |
|---|---|
| Suspension ball joint worn Major | 2.5 |
| Catalyst emissions: Lambda reading after 2nd fast idle outside specified limits Major | 2 |
| Malfunction indicator lamp: inoperative or indicates a malfunction Major | 1.2 |
Out of 19,511 MOTs. A test with two faults counts twice.
Wear and upkeep
| Fail item | Per 100 MOTs |
|---|---|
| Tyre tread below 1.6 mm Dangerous | 4.8 |
| Wipers not clearing screen Major | 4 |
| Brake light not working Major | 2.8 |
| Tyre with cords exposed Dangerous | 2.1 |
| Washers: provides insufficient washer liquid Major | 2.1 |
| Brake pads under 1.5 mm Dangerous | 2 |
| Tyre condition: has a cut in excess of the requirements deep enough to reach the ply or cords Major | 1.5 |
Out of 19,511 MOTs. A test with two faults counts twice.
Other models at 7 years
| Model | MOT fail rate | Tests (n) | All cars |
|---|---|---|---|
| Smart Fortwo | 18.4% | 16,164 | 20.6% |
| Ford Fiesta | 25.4% | 430,004 | 20.6% |
| Vauxhall Corsa | 26.1% | 272,589 | 20.6% |
MOT fail rate by first-use year
Each year has its own page: the fail rate for cars first used that year at each MOT from 2022 to 2025 with at least 1,000 tests, the most common faults at that age, and the car tax and ULEZ rules for that year.
First-use year data updated .
| First used | Age at test | MOT fail rate | Tests (n) | All cars |
|---|---|---|---|---|
| 2005 | 19 years in 2024 | 43.7% | 1,034 | 43.2% |
| 2006 | 18 years in 2024 | 43.1% | 1,015 | 43.3% |
| 2015 | 10 years in 2025 | 33.8% | 5,445 | 30.3% |
| 2016 | 9 years in 2025 | 29.2% | 5,294 | 27.1% |
| 2017 | 8 years in 2025 | 24.1% | 4,761 | 23.8% |
| 2018 | 7 years in 2025 | 20.4% | 3,797 | 20.6% |
| 2019 | 6 years in 2025 | 19.0% | 1,954 | 17.8% |
More on the Smart Forfour
Looking at one Smart Forfour?
These are figures for the model, not for one car. The VetTheCar Buying Report looks at a single car: its MOT tests, defects, advisories and mileage readings.
Source
Contains public sector information licensed under the Open Government Licence v3.0. Source: DVSA anonymised MOT test data, class 4 normal MOT tests, 2022 to 2025. MOT data updated 22 September 2026.
Not affiliated with or endorsed by DVSA. How we calculate these figures · Data sources