Does the Smart Roadster fail the MOT on noise, emissions and leaks more than it should?
The Smart Roadster records 4.09 noise, emissions and leaks failure items per 100 initial MOT tests (2019–2024), against 9.05 expected for a car of the same age mix: less than expected for its class and age (−4.96, 95% interval −5.50 to −4.42). It ranks 660 of 678 models on noise, emissions and leaks (1 = most failures above expected).
Data release dvsa-2024-v2 (24 Sep 2026) · page updated 30 Sep 2026 · all models on noise, emissions and leaks · check a Smart Roadster by registration
What exactly fails on noise, emissions and leaks?
The most frequent DVSA defect wording in this group on the Smart Roadster is “Lambda coefficient outside the default limits or the range specified by the manufacturer”, recorded 113 times in 2019–2024.
| DVSA defect wording | Items | Per 100 tests |
|---|---|---|
| Lambda coefficient outside the default limits or the range specified by the manufacturer | 113 | 0.94 |
| Emissions levels exceed default limits | 107 | 0.89 |
| Engine MIL illuminated indicating a malfunction | 96 | 0.80 |
| Emissions levels exceed the manufacturer's specified limits | 62 | 0.52 |
| Emissions test unable to be completed | 52 | 0.43 |
Source: DVSA MOT bulk data (OGL v3.0) · Window: 2019–2024 · n = 11,977 (initial tests) · Method: failure items (major and minor) grouped by DVSA's defect tree; wordings with 30+ items · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV
If a Smart Roadster gets a noise, emissions and leaks advisory, how often does it fail next time?
3.2% of Smart Roadster MOTs with a noise, emissions and leaks advisory were followed by a fail in the same group at the next MOT, typically 12.5 months and 1,964 miles later (842 advisories followed).
Source: DVSA MOT bulk data (OGL v3.0) · Window: 2019–2024 · n = 842 (advisories followed) · Method: the same vehicles followed to their next ordinary MOT · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV
Other pages for this model
Smart Roadster 2003 · Smart Roadster 2004 · Smart Roadster 2005 · Smart Roadster 2006 · Smart Roadster 2007 · Smart Roadster in the Netherlands · Smart Roadster by postcode area · Smart Roadster body, chassis and structure failures · Smart Roadster brakes failures · Smart Roadster vehicle identification failures · Smart Roadster lamps, reflectors and electrics failures · Smart Roadster road wheels failures · Smart Roadster seat belts and airbags failures · Smart Roadster steering failures · Smart Roadster suspension failures · Smart Roadster tyres failures · Smart Roadster visibility failures