Smart Forfour 2004: MOT failure rate for its age
46.9% of 3,594 MOT tests of the Smart Forfour first registered in 2004 failed at the first attempt (2019–2024; retests excluded). Against this model's own normal rate at the same ages the index is 103.3 (95% CI 98.4–108.3; 100 = normal for this model at that age): the 2004 build year is no different from other years of the same model at the same age. This is a rough estimate from a smaller sample.
| Measure | Value | Unit | Compared with | Years | Tests |
|---|---|---|---|---|---|
| Failed first time | 46.9 | % | all ages tested | 2019–2024 | 3594 |
| Index against this model at the same age (95% CI 98.4–108.3) | 103.3 | index | 100 = normal for this model at that age | 2019–2024 | 3594 |
| Rank among this model's 9 build years | 8 | of 9 | 1 = fails least for its age | 2019–2024 | 3594 |
| Tested in 2024 | 361 | tests | median 104,401 miles | 2024 | 361 |
Data release dvsa-2024-v2 (24 Sep 2026) · page updated 30 Sep 2026 · full dataset (v5).
How does the 2004 Smart Forfour fail at each age?
Cars built in 2004 were tested at ages 15 to 20 between 2019 and 2024. Each row compares their first-time failure share with what this model normally shows at that age, after allowing for the overall failure level of each test year.
| Age | Tests | Failed, % | 95% interval | Normal for this model at that age, % | Index (100 = normal) |
|---|---|---|---|---|---|
| 15 | 1,067 | 49.9 | 46.9–52.9 | 49.7 | 100.4 |
| 16 | 847 | 45.2 | 41.9–48.6 | 44.3 | 102 |
| 17 | 678 | 47.9 | 44.2–51.7 | 44.3 | 108.3 |
| 18 | 551 | 46.1 | 42–50.3 | 42.7 | 107.9 |
| 19 | 451 (rough estimate) | 42.8 | 38.3–47.4 | 42.5 | 100.6 |
| 20 | 361 (rough estimate) | 48.2 | 43.1–53.3 | not available | not available |
Source: DVSA MOT bulk data · Window: 2019–2024 · n = 3,955 (initial tests) · Method: normal rate = this model's first-time failure share at that age across its build years (cells of 400+ tests), adjusted for each test year's overall level; cells of 30+ tests, under 500 marked rough · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV
What fails most on the 2004 Smart Forfour?
The most common failure group on cars built in 2004 is lamps, reflectors and electrical equipment: 70 items per 100 first tests, against 14.2 across all build years of the Smart Forfour. These counts are not age-adjusted: cars built in 2004 were tested at ages 15 to 20.
| Failure group | Built 2004, per 100 | All build years, per 100 | Items |
|---|---|---|---|
| Lamps, reflectors and electrical equipment | 70 | 14.2 | 2,767 |
| Brakes | 28.4 | 7.1 | 1,122 |
| Suspension | 27.5 | 7.5 | 1,087 |
| Visibility | 15.2 | 8.9 | 603 |
| Body, chassis, structure | 14.8 | 2.8 | 586 |
Source: DVSA MOT bulk data · Window: 2019–2024 · n = 3,955 (initial tests of this build year) · Method: failure items grouped by DVSA's top-level defect groups, per 100 initial tests; groups with 30+ items · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV
How does 2004 compare with the years around it?
Among the 9 published build years of the Smart Forfour, 2004 ranks 8 (1 = fails least for its age). 2005: index 99.2.
| Build year | Index (100 = normal) | 95% interval | Verdict | Tests |
|---|---|---|---|---|
| 2004 | 103.3 | 98.4–108.3 | no different (rough estimate) | 3,594 |
| 2005 | 99.2 | 96.3–102.1 | no different | 10,374 |
| 2006 | 96.7 | 93.6–99.7 | better | 8,887 |
| 2007 | 95.2 | 84.2–106.2 | no different (rough estimate) | 702 |
| 2015 | 105.6 | 103.3–107.9 | worse | 33,221 |
| 2016 | 102.7 | 100.2–105.1 | worse | 31,503 |
| 2017 | 98.2 | 95.3–101.0 | no different | 25,286 |
| 2018 | 94.4 | 90.7–98.1 | better | 15,417 |
| 2019 | 92.3 | 86.2–98.4 | better | 5,911 |
Source: DVSA MOT bulk data · Window: 2019–2024 · n = 134,895 (initial tests) · Method: observed failures against those expected for the same model at the same ages, test-year level adjusted; verdict follows the printed one-decimal bound · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV
How to cite this page
MOT Risk Index (2026). Smart Forfour 2004 MOT statistics (data release dvsa-2024-v2; full dataset motriskindex-families-2024-v5, DOI 10.5281/zenodo.22975051), updated 30 September 2026. motriskindex.co.uk/cars/smart-forfour/2004/
How every figure is calculated: methodology. Age, test year and build year are tied together (age = test year − build year), so the test-year level is taken as observed, not estimated.
Other pages for this model
Smart Forfour 2005 · Smart Forfour 2006 · Smart Forfour 2007 · Smart Forfour 2015 · Smart Forfour 2016 · Smart Forfour 2017 · Smart Forfour 2018 · Smart Forfour 2019 · Smart Forfour in Finland · Smart Forfour in the Netherlands · Smart Forfour by postcode area · Smart Forfour body, chassis and structure failures · Smart Forfour brakes failures · Smart Forfour vehicle identification failures · Smart Forfour lamps, reflectors and electrics failures · Smart Forfour noise, emissions and leaks failures · Smart Forfour road wheels failures · Smart Forfour seat belts and airbags failures · Smart Forfour steering failures · Smart Forfour suspension failures · Smart Forfour tyres failures · Smart Forfour visibility failures