Mercedes-Benz SLK 2004: MOT failure rate for its age

34.9% of 15,686 MOT tests of the Mercedes-Benz SLK 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 108.5 (95% CI 105.6–111.3; 100 = normal for this model at that age): the 2004 Mercedes-Benz SLK fails more often than other build years of the same model at the same age.

Mercedes-Benz SLK built in 2004 at a glance
Measure	Value	Unit	Compared with	Years	Tests
Failed first time	34.9	%	all ages tested	2019–2024	15686
Index against this model at the same age (95% CI 105.6–111.3)	108.5	index	100 = normal for this model at that age	2019–2024	15686
Rank among this model's 18 build years	17	of 18	1 = fails least for its age	2019–2024	15686
Tested in 2024	3010	tests	median 81,509 miles	2024	3010

Built 2004 against Mercedes-Benz SLK normal for the age: first-time MOT failure share at each age, age 15: 34.8% vs 33.9%; age 16: 32.6% vs 32.6%; age 17: 35.6% vs 32.3%; age 18: 35.5% vs 32.1%; age 19: 34.6% vs 31.7%; age 20: 35% vs 31.8%. Axis from 0% to 40%. DVSA MOT bulk data, 2019–2024.

Check a 2004 Mercedes-Benz SLK by registration · All Mercedes-Benz SLK 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 2004 Mercedes-Benz SLK 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.

Mercedes-Benz SLK built 2004: 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)
15	1,368	34.8	32.3–37.4	33.9	102.7
16	1,214	32.6	30–35.3	32.6	100.1
17	3,484	35.6	34–37.2	32.3	110
18	3,379	35.5	33.9–37.1	32.1	110.4
19	3,231	34.6	33–36.3	31.7	109.3
20	3,010	35	33.3–36.7	31.8	109.8

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 15,686 (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 Mercedes-Benz SLK?

The most common failure group on cars built in 2004 is suspension: 24.4 items per 100 first tests, against 15.7 across all build years of the Mercedes-Benz SLK. These counts are not age-adjusted: cars built in 2004 were tested at ages 15 to 20.

Failure items per 100 first tests, Mercedes-Benz SLK built 2004 against the Mercedes-Benz SLK in all build years (2019–2024, not age-adjusted)
Failure group	Built 2004, per 100	All build years, per 100	Items
Suspension	24.4	15.7	3,835
Lamps, reflectors and electrical equipment	22.1	12.2	3,467
Brakes	13.9	9.1	2,185
Tyres	7.8	8.9	1,226
Visibility	7.1	5.7	1,116

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 15,686 (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 18 published build years of the Mercedes-Benz SLK, 2004 ranks 17 (1 = fails least for its age). 2003: index 105.0. 2005: index 100.3.

Mercedes-Benz SLK build years: index against the model at the same age (2019–2024)
Build year	Index (100 = normal)	95% interval	Verdict	Tests
1999	105.1	97.1–113.1	no different (rough estimate)	2,058
2000	99.5	95.3–103.7	no different	6,728
2001	97.1	93.7–100.5	no different	10,092
2002	95.1	91.7–98.4	better	10,334
2003	105.0	101.3–108.8	worse	8,913
2004	108.5	105.6–111.3	worse	15,686
2005	100.3	98.1–102.6	no different	23,960
2006	100.2	97.6–102.9	no different	17,113
2007	102.6	99.8–105.5	no different	15,823
2008	103.1	100.1–106.2	worse	14,696
2009	105.6	102.0–109.2	worse	11,542
2010	107.8	103.8–111.9	worse	9,750
2011	90.1	86.5–93.7	better	11,156
2012	101.1	98.5–103.6	no different	27,991
2013	108.6	105.8–111.4	worse	27,606
2014	97.9	95.2–100.7	no different	29,492
2015	95.3	92.4–98.2	better	28,951
2016	91.1	85.3–96.9	better	7,462

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 279,353 (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 SLK 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/mercedes-slk/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.

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