Does the Daihatsu Sirion fail the MOT on noise, emissions and leaks more than it should?
The Daihatsu Sirion records 5.50 noise, emissions and leaks failure items per 100 initial MOT tests (2019–2024), against 7.34 expected for a car of the same age mix: less than expected for its class and age (−1.84, 95% interval −2.09 to −1.59). It ranks 531 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 Daihatsu Sirion by registration
What exactly fails on noise, emissions and leaks?
The most frequent DVSA defect wording in this group on the Daihatsu Sirion is “Lambda coefficient outside the default limits or the range specified by the manufacturer”, recorded 648 times in 2019–2024.
| DVSA defect wording | Items | Per 100 tests |
|---|---|---|
| Lambda coefficient outside the default limits or the range specified by the manufacturer | 648 | 1.39 |
| Engine MIL illuminated indicating a malfunction | 574 | 1.23 |
| Emissions test unable to be completed | 434 | 0.93 |
| Emissions levels exceed default limits | 368 | 0.79 |
| An induction or exhaust leak that could affect emissions levels | 216 | 0.46 |
Source: DVSA MOT bulk data (OGL v3.0) · Window: 2019–2024 · n = 46,528 (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 Daihatsu Sirion gets a noise, emissions and leaks advisory, how often does it fail next time?
9.4% of Daihatsu Sirion MOTs with a noise, emissions and leaks advisory were followed by a fail in the same group at the next MOT, typically 12 months and 3,367 miles later (1,277 advisories followed).
Source: DVSA MOT bulk data (OGL v3.0) · Window: 2019–2024 · n = 1,277 (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
Daihatsu Sirion 2001 · Daihatsu Sirion 2002 · Daihatsu Sirion 2003 · Daihatsu Sirion 2004 · Daihatsu Sirion 2005 · Daihatsu Sirion 2006 · Daihatsu Sirion 2007 · Daihatsu Sirion 2008 · Daihatsu Sirion 2009 · Daihatsu Sirion 2010 · Daihatsu Sirion in the Netherlands · Daihatsu Sirion by postcode area · Daihatsu Sirion body, chassis and structure failures · Daihatsu Sirion brakes failures · Daihatsu Sirion vehicle identification failures · Daihatsu Sirion lamps, reflectors and electrics failures · Daihatsu Sirion seat belts and airbags failures · Daihatsu Sirion steering failures · Daihatsu Sirion suspension failures · Daihatsu Sirion tyres failures · Daihatsu Sirion visibility failures