Mercedes-Benz S-Class 2009: MOT failure rate for its age

27.8% of 5,425 MOT tests of the Mercedes-Benz S-Class first registered in 2009 failed at the first attempt (2019–2024; retests excluded). Against this model's own normal rate at the same ages the index is 113.5 (95% CI 107.8–119.3; 100 = normal for this model at that age): the 2009 Mercedes-Benz S-Class fails more often than other build years of the same model at the same age.

Mercedes-Benz S-Class built in 2009 at a glance
Measure	Value	Unit	Compared with	Years	Tests
Failed first time	27.8	%	all ages tested	2019–2024	5425
Index against this model at the same age (95% CI 107.8–119.3)	113.5	index	100 = normal for this model at that age	2019–2024	5425
Rank among this model's 22 build years	22	of 22	1 = fails least for its age	2019–2024	5425
Tested in 2024	826	tests	median 107,230 miles	2024	826

Built 2009 against Mercedes-Benz S-Class normal for the age: first-time MOT failure share at each age, age 10: 28.2% vs 22.7%; age 11: 27.9% vs 23.7%; age 12: 29.5% vs 25.3%; age 13: 27.2% vs 24%; age 14: 26% vs 25%; age 15: 28.1% vs 26.2%. Axis from 0% to 30%. DVSA MOT bulk data, 2019–2024.

Check a 2009 Mercedes-Benz S-Class by registration · All Mercedes-Benz S-Class MOT statistics · Download the build-year table (CSV)

Data release dvsa-2024-v2 (24 Sep 2026) · page updated 30 Sep 2026 · full dataset (v5).

How does the 2009 Mercedes-Benz S-Class fail at each age?

Cars built in 2009 were tested at ages 10 to 15 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.

Mercedes-Benz S-Class built 2009: first-time MOT failure by age, against the model's normal rate at that age (2019–2024)
Age	Tests	Failed, %	95% interval	Normal for this model at that age, %	Index (100 = normal)
10	847	28.2	25.3–31.3	22.7	124.2
11	759	27.9	24.9–31.2	23.7	117.8
12	1,044	29.5	26.8–32.3	25.3	116.4
13	1,000	27.2	24.5–30	24	113.5
14	949	26	23.3–28.9	25	104.1
15	826	28.1	25.1–31.2	26.2	107.3

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 5,425 (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 2009 Mercedes-Benz S-Class?

The most common failure group on cars built in 2009 is brakes: 17.5 items per 100 first tests, against 8.4 across all build years of the Mercedes-Benz S-Class. These counts are not age-adjusted: cars built in 2009 were tested at ages 10 to 15.

Failure items per 100 first tests, Mercedes-Benz S-Class built 2009 against the Mercedes-Benz S-Class in all build years (2019–2024, not age-adjusted)
Failure group	Built 2009, per 100	All build years, per 100	Items
Brakes	17.5	8.4	949
Suspension	15.4	9.2	836
Tyres	9.5	7.6	513
Lamps, reflectors and electrical equipment	8.4	6.7	458
Noise, emissions and leaks	8.2	2.8	445

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 5,425 (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 2009 compare with the years around it?

Among the 22 published build years of the Mercedes-Benz S-Class, 2009 ranks 22 (1 = fails least for its age). 2008: index 106.9. 2010: index 98.8.

Mercedes-Benz S-Class build years: index against the model at the same age (2019–2024)
Build year	Index (100 = normal)	95% interval	Verdict	Tests
1999	91.1	76.7–105.5	no different (rough estimate)	507
2000	110.7	99.7–121.7	no different (rough estimate)	1,114
2001	103.9	95.3–112.5	no different (rough estimate)	1,795
2002	108.1	100.5–115.7	worse (rough estimate)	2,421
2003	101.6	95.6–107.5	no different (rough estimate)	3,909
2004	99.9	93.6–106.1	no different (rough estimate)	3,540
2005	110.0	102.8–117.1	worse (rough estimate)	3,079
2006	95.1	90.6–99.5	better	6,903
2007	103.0	98.7–107.2	no different	8,514
2008	106.9	101.8–112.0	worse	6,185
2009	113.5	107.8–119.3	worse	5,425
2010	98.8	93.3–104.3	no different	5,469
2011	99.8	94.2–105.3	no different	5,755
2012	112.9	107.5–118.3	worse	7,579
2013	113.3	106.7–119.8	worse	5,891
2014	86.2	81.5–90.9	better	9,855
2015	96.3	91.8–100.9	no different	13,759
2016	100.2	95.7–104.7	no different	16,005
2017	99.0	93.9–104.2	no different	13,529
2018	85.8	80.1–91.6	better	10,153
2019	88.0	80.9–95.1	better	7,309
2020	75.1	49.8–100.3	no different (rough estimate)	522

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 139,218 (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). Mercedes-Benz S-Class 2009 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/mercedes-s-class/2009/

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.

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