MOT fail rates by first-use year
2018 Smart Forfour MOT fail rate and common faults
How Smart Forfour cars first used in 2018 did at their MOTs from 2022 to 2025, against all cars of the same age. From 15,416 DVSA MOT tests of these cars. First use is usually the date the car was first registered.
MOT data updated
At 7 years, tested in 2025
What stands out
- In 2025, at 7 years old, Smart Forfour cars first used in 2018 failed 20.4% of MOTs (3,797 tests), about the same as the 20.6% for all cars that age.
- From 2022 to 2025, as these cars went from 4 to 7 years old, the fail rate moved from 16.5% to 20.4%.
- Smart Forfour cars first used a year earlier, in 2017, failed 23.1% at the same age of 7 years (4,804 tests, in 2024).
- The most common fail item that is not a wear item, for the Smart Forfour at 7 years, is suspension ball joint worn, at 2.3 per 100 MOTs (all cars: 0.7).
MOT fail rate by test year
| Test year | Age | MOT fail rate | Tests (n) | All cars | Difference |
|---|---|---|---|---|---|
| 2022 | 4 years | 16.5% | 3,876 | 13.4% | +3.1 pts |
| 2023 | 5 years | 16.5% | 3,882 | 15.3% | +1.2 pts |
| 2024 | 6 years | 18.8% | 3,861 | 17.8% | +1.0 pts |
| 2025 | 7 years | 20.4% | 3,797 | 20.6% | −0.2 pts |
Most common faults at 7 years
These figures cover all Smart Forfour MOTs (first used 2014 or later) at 7 years: cars first used 2015 to 2018, tested 2022 to 2025 (n=19,511). The list uses every first-use year so it has enough tests. Wear items (tyres, brake pads, wipers, bulbs) say more about upkeep than about the design.
MOT fail items
| Fail item | Per 100 MOTs | All cars |
|---|---|---|
| Tyre tread below 1.6 mm Wear | 3.4 | 2.2 |
| Wipers not clearing screen Wear | 3.3 | 1.7 |
| Brake light not working Wear | 2.6 | 0.9 |
| Suspension ball joint worn | 2.3 | 0.7 |
| Catalyst emissions: Lambda reading after 2nd fast idle outside specified limits | 2.0 | 0.2 |
| Washers: provides insufficient washer liquid Wear | 1.9 | 1.0 |
| Tyre with cords exposed Wear | 1.8 | 1.1 |
| Brake pads under 1.5 mm Wear | 1.8 | 2.0 |
| Tyre condition: has a cut in excess of the requirements deep enough to reach the ply or cords Wear | 1.3 | 1.3 |
| Engine warning lamp at the petrol emissions check: not working or showing a fault | 1.2 | 0.6 |
Per 100 of the MOTs above (n=19,511). A test with two items counts once for each.
Advisories
| Advisory | Per 100 MOTs | All cars |
|---|---|---|
| Tyre tread close to the legal limit or worn on the edge Wear | 17.5 | 15.0 |
| Brake discs: worn, pitted or scored, but not seriously weakened | 9.9 | 8.0 |
| Tyre condition: slightly damaged/cracking or perishing Wear | 9.5 | 8.9 |
| Brake pads wearing thin Wear | 6.0 | 9.0 |
| Brake discs: worn, but not excessively | 4.2 | 2.6 |
| Tyre tread close to the legal limit, under the 1.0 mm rule Wear | 2.4 | 2.0 |
| Non-component advisories: Child Seat fitted not allowing full inspection of adult belt | 1.7 | 2.4 |
| Suspension pin or bush worn, without excessive movement | 1.5 | 3.0 |
| Wipers: blade defective Wear | 1.4 | 1.0 |
| Windscreen: damaged but not adversely affecting driver's view | 1.3 | 1.9 |
Per 100 of the MOTs above (n=19,511). A test with two items counts once for each.
Fuel type at 7 years
These figures cover all Smart Forfour MOTs (first used 2014 or later) at 7 years: cars first used 2015 to 2018, tested 2022 to 2025 (n=19,511). Each fuel is set against all cars of the same fuel and age. Fuels with fewer than 1,000 tests are not shown.
| Fuel | Share of tests | MOT fail rate | Tests (n) | All cars, same fuel | Median mileage |
|---|---|---|---|---|---|
| Petrol | 98.9% | 24.1% | 19,287 | 19.6% | 36,837 miles |
Fail rate by mileage at 7 years
These figures cover all Smart Forfour MOTs (first used 2014 or later) at 7 years: cars first used 2015 to 2018, tested 2022 to 2025 (n=19,511). At 7 years, Smart Forfour cars at 60,000 to 90,000 miles failed more often (33.9%, n=2,080) than those at under 30,000 miles (16.2%, n=6,582). Bands with fewer than 1,000 tests are not shown.
| Mileage at test | MOT fail rate | Tests (n) | All cars |
|---|---|---|---|
| Under 30,000 miles | 16.2% | 6,582 | 12.7% |
| 30,000 to 60,000 miles | 26.7% | 10,472 | 19.2% |
| 60,000 to 90,000 miles | 33.9% | 2,080 | 24.2% |
Car tax rules for a 2018 car
- Cars first registered from 1 April 2017 pay a first-year rate set by CO2 emissions, then the standard rate each year. A petrol, diesel or hybrid car with a list price over £40,000 also pays the expensive car supplement for five years, from the second tax payment.
- Electric cars have paid vehicle tax since 1 April 2025, under the rules for their registration date.
- Electric cars registered before 1 April 2025 do not pay the expensive car supplement.
These are the rules, not the amount for a specific car. Car tax check
ULEZ and clean air zones
- Petrol cars first registered from 2006 usually meet Euro 4, the petrol standard for the London ULEZ, so they usually do not pay the daily charge.
- Fully electric cars do not pay the ULEZ charge.
- The clean air zones in Birmingham and Bristol use the same Euro 4 petrol and Euro 6 diesel standards. The low emission zones in Scotland use them too, but enforce them with fines, not a daily charge.
The Euro standard of the car decides, not the year alone. ULEZ checker
Other years of the Smart Forfour
Other Smart models first used in 2018
| Model | Age at test | MOT fail rate | Tests (n) | All cars |
|---|---|---|---|---|
| Smart Fortwo (2018) | 7 years in 2025 | 16.9% | 3,383 | 20.6% |
More on the Smart Forfour
Found one you might buy? Vet the specific car.
These figures describe 2018 Smart Forfour cars as a group, not any one car. The VetTheCar Buying Report looks at the car you are buying: its MOT history, what similar cars did next, and what to ask the seller.
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 28 September 2026.
Not affiliated with or endorsed by DVSA. How we calculate these figures · Data sources
Car tax and clean air zone rules are summarised from GOV.UK and Transport for London guidance. They are general rules and are not drawn from the MOT data.