Smart (mcc) Forfour common problems by mileage
What UK MOT testers flag on the Smart (mcc) Forfour at each age and mileage, compared with all cars.
In 23,073 UK MOT tests of the Smart (mcc) Forfour in 2023, the problem that most sets it apart from other cars is catalyst emissions (Lambda reading after 2nd fast idle outside specified limits): recorded on 4.7% of tests of 2015–2017 cars at 60k–80k mi (97k–129k km), 24× the rate for all cars of that age and mileage. Other stand-out issues: ball joint (ball joint excessively worn) (5.3×); stop lamp (not working) (4.5×); brake discs (worn, but not excessively) (2.7×). The most common reasons a Smart (mcc) Forfour fails its MOT are tyres (tread depth below requirements of 1.6mm); wipers (does not clear the windscreen effectively); stop lamp (not working).
Last updated: · Source: DVSA anonymised MOT data 2023
What stands out on the Smart (mcc) Forfour
Parts that MOT testers flag clearly more often on the Smart (mcc) Forfour than on all cars of the same age at the same mileage (at least 1.5× the rate and 3% of tests).
| Issue | Type | First used | Mileage | Share of tests | All cars this age | Ratio | Tests |
|---|---|---|---|---|---|---|---|
| Catalyst emissions: Lambda reading after 2nd fast idle outside specified limits | MOT fail | 2015–2017 | 60k–80k mi (97k–129k km) | 4.7% | 0.2% | 24× | 1,607 |
| Ball joint: ball joint excessively worn | MOT fail | 2015–2017 | 40k–60k mi (64k–97k km) | 3.7% | 0.7% | 5.3× | 4,885 |
| Stop lamp: not working | MOT fail | 2015–2017 | 40k–60k mi (64k–97k km) | 4.5% | 1% | 4.5× | 4,885 |
| Brake discs: worn, but not excessively | Advisory | 2017–2019 | 20k–40k mi (32k–64k km) | 5.4% | 2% | 2.7× | 4,802 |
| Wipers: does not clear the windscreen effectively | MOT fail | 2018–2020 | 0k–20k mi (0k–32k km) | 4.5% | 1.8% | 2.5× | 2,553 |
| Linkage ball joints: ball joint has slight play | Advisory | 2004–2006 | 100k–120k mi (161k–193k km) | 9.4% | 2.9% | 3.2× | 319 |
| Tyres (tread depth): tread depth below requirements of 1.6mm | MOT fail | 2016–2018 | 40k–60k mi (64k–97k km) | 5.1% | 2.3% | 2.2× | 3,263 |
| Brake discs: worn, pitted or scored, but not seriously weakened | Advisory | 2018–2020 | 0k–20k mi (0k–32k km) | 5.5% | 3.1% | 1.8× | 2,553 |
Smart (mcc) Forfour by mileage (2015–2017 cars)
The most-tested first-use years. For each mileage band: how many MOT tests, the most common item, and the item that stands out most against other cars.
| Mileage | Tests | Most common | Stands out |
|---|---|---|---|
| 0k–20k mi (0k–32k km) | 2,078 | Tyres (condition): slightly damaged/cracking or perishing (15%) | Wipers: does not clear the windscreen effectively (3.8%, 1.7×) |
| 20k–40k mi (32k–64k km) | 6,507 | Tyres (tread depth): worn close to legal limit/worn on edge (16%) | Brake discs: worn, but not excessively (5.1%, 2.3×) |
| 40k–60k mi (64k–97k km) | 4,885 | Tyres (tread depth): worn close to legal limit/worn on edge (21%) | Ball joint: ball joint excessively worn (3.7%, 5.3×) |
| 60k–80k mi (97k–129k km) | 1,607 | Tyres (tread depth): worn close to legal limit/worn on edge (25%) | Catalyst emissions: Lambda reading after 2nd fast idle outside specified limits (4.7%, 24×) |
| 80k–100k mi (129k–161k km) | 419 | Tyres (tread depth): worn close to legal limit/worn on edge (23%) | Ball joint: ball joint excessively worn (6%, 5×) |
Smart (mcc) Forfour by first-use year
| First used | Tests | Biggest stand-out issue |
|---|---|---|
| 2005 | 726 | Linkage ball joints: ball joint has slight play at 100k–120k mi (161k–193k km) (3.2×) |
| 2006 | 553 | Linkage ball joints: ball joint has slight play at 80k–100k mi (129k–161k km) (2.9×) |
| 2015 | 5,547 | Catalyst emissions: Lambda reading after 2nd fast idle outside specified limits at 60k–80k mi (97k–129k km) (18×) |
| 2016 | 5,282 | Catalyst emissions: Lambda reading after 2nd fast idle outside specified limits at 60k–80k mi (97k–129k km) (24×) |
| 2017 | 4,795 | Stop lamp: not working at 60k–80k mi (97k–129k km) (4.3×) |
| 2018 | 3,861 | Brake discs: worn, but not excessively at 20k–40k mi (32k–64k km) (2.7×) |
| 2019 | 1,955 | Brake discs: worn, but not excessively at 20k–40k mi (32k–64k km) (2.8×) |
How these numbers are made
From the DVSA anonymised MOT data for 2023: every normal MOT test of a car in Great Britain, with its mileage and every advisory and failure item. For each first-use year (pooled with the years either side) and 20,000-mile band we count the share of tests where a part was recorded, and compare it with the same share for every car of that age at that mileage. A cell is shown only with 300 or more tests. Advisories are tester notes, not failures. Figures describe UK-market cars; engines and equipment can differ in other countries.
Contains public sector information licensed under the Open Government Licence v3.0 (DVSA anonymised MOT data, 2023).
Frequently asked questions
What are the most common problems with the Smart (mcc) Forfour?
In 23,073 UK MOT tests of the Smart (mcc) Forfour in 2023, the problem that most sets it apart from other cars is catalyst emissions (Lambda reading after 2nd fast idle outside specified limits): recorded on 4.7% of tests of 2015–2017 cars at 60k–80k mi (97k–129k km), 24× the rate for all cars of that age and mileage. Other stand-out issues: ball joint (ball joint excessively worn) (5.3×); stop lamp (not working) (4.5×); brake discs (worn, but not excessively) (2.7×). The most common reasons a Smart (mcc) Forfour fails its MOT are tyres (tread depth below requirements of 1.6mm); wipers (does not clear the windscreen effectively); stop lamp (not working).
Why do Smart (mcc) Forfours fail the MOT?
Across 23,073 MOT tests in 2023, the most common failure items on the Smart (mcc) Forfour were tyres (tread depth below requirements of 1.6mm) (3.9% of tests); wipers (does not clear the windscreen effectively) (4% of tests); stop lamp (not working) (4.4% of tests).
At what mileage do Smart (mcc) Forfour problems start?
The clearest Smart (mcc) Forfour-specific issue, catalyst emissions (Lambda reading after 2nd fast idle outside specified limits), peaks against other cars at 60k–80k mi (97k–129k km) on 2015–2017 cars (4.7% of tests vs 0.2% for all cars that age).
Where does this Smart (mcc) Forfour data come from?
From the UK government's anonymised MOT test data (DVSA, 2023, Open Government Licence v3.0): 23,073 tests of the Smart (mcc) Forfour. VinSnap shows the same numbers for your own car's age and mileage in the app.