Does the Porsche 911 fail the MOT on noise, emissions and leaks more than it should?
The Porsche 911 records 2.50 noise, emissions and leaks failure items per 100 initial MOT tests (2019–2024), against 6.32 expected for a car of the same age mix: less than expected for its class and age (−3.82, 95% interval −3.91 to −3.73). It ranks 638 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 Porsche 911 by registration
What exactly fails on noise, emissions and leaks?
The most frequent DVSA defect wording in this group on the Porsche 911 is “Lambda coefficient outside the default limits or the range specified by the manufacturer”, recorded 3,185 times in 2019–2024.
| DVSA defect wording | Items | Per 100 tests |
|---|---|---|
| Lambda coefficient outside the default limits or the range specified by the manufacturer | 3,185 | 1.11 |
| Emissions levels exceed default limits | 1,288 | 0.45 |
| Emissions test unable to be completed | 624 | 0.22 |
| Engine MIL illuminated indicating a malfunction | 589 | 0.21 |
| Emissions levels exceed the manufacturer's specified limits | 532 | 0.19 |
Source: DVSA MOT bulk data (OGL v3.0) · Window: 2019–2024 · n = 285,717 (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 Porsche 911 gets a noise, emissions and leaks advisory, how often does it fail next time?
4.5% of Porsche 911 MOTs with a noise, emissions and leaks advisory were followed by a fail in the same group at the next MOT, typically 12.2 months and 925 miles later (8,719 advisories followed).
Source: DVSA MOT bulk data (OGL v3.0) · Window: 2019–2024 · n = 8,719 (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
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