The picture
Cls: middle-of-the-pack on first-time pass
Across 30,217 MOT tests, the Cls returns 78.5% first-time pass — roughly in line with the UK fleet average. The single most-logged Major fail is a corroded brake pipe. A tyre with the cords showing and a broken or weak spring round out the top three. Average tested mileage sits at 88,160, which is the lens to read those failure rankings through. If you own one and the next test is close, the ranked list below is a sensible pre-test checklist.
Top ten reasons for rejection.
- 01
Brake pipe damaged or excessively corroded
1,017 occurrences · 3.4% of tests
- 02
A tyre cords visible or damaged
989 occurrences · 3.3% of tests
- 03
A spring or spring component fractured or seriously weakened
930 occurrences · 3.1% of tests
- 04
Tyre tread depth not in accordance with the requirements
862 occurrences · 2.9% of tests
- 05
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
800 occurrences · 2.6% of tests
- 06
A suspension pin, bush or joint excessively worn
662 occurrences · 2.2% of tests
- 07
A tyre seriously damaged
602 occurrences · 2.0% of tests
- 08
A tyre seriously damaged
426 occurrences · 1.4% of tests
- 09
A suspension joint dust cover severely deteriorated
392 occurrences · 1.3% of tests
- 10
Any fracture or welding defect on a wheel
314 occurrences · 1.0% of tests
Counts cover Major and Dangerous defects logged at test. Advisory items excluded so this shows why a car was rejected, not just what the tester flagged in passing.
Worst-case fix budget · top 4 failures
£240–£520
If every one of this Cls's most-logged Major fails hit at the same MOT, that's the real-world UK garage range. Reality is usually one or two items, not all of them. Open the estimator →
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Tools that pre-empt a retest.
Picked against this car's top failure patterns. Affiliate links to Amazon UK — we earn a small cut at no cost to you. Disclosed up-front, doesn't shape the data.
Buying or keeping a Cls?
Use the failure ranking as a pre-test checklist or a haggling lever. Treat the headline pass rate as a fleet-wide trend, not a guarantee on any individual car.
If you own a Cls and your last MOT looked nothing like the ranked failures above, that's normal — individual cars vary widely. The ranking shows the patterns testers flag most often across the country.