The picture
Cl 500: middle-of-the-pack on first-time pass
Across 2,206 MOT tests, the Cl 500 returns 79.4% first-time pass — roughly in line with the UK fleet average. The single most-logged Major fail is worn suspension bushes. A corroded brake pipe and windscreen damage round out the top three. Average tested mileage sits at 96,307, 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
A suspension pin, bush or joint excessively worn
68 occurrences · 3.1% of tests
- 02
Brake pipe damaged or excessively corroded
65 occurrences · 2.9% of tests
- 03
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
65 occurrences · 2.9% of tests
- 04
A suspension joint dust cover severely deteriorated
65 occurrences · 2.9% of tests
- 05
A rear registration plate lamp or light source missing or inoperative in the case of multiple lamps or light sources
56 occurrences · 2.5% of tests
- 06
A shock absorber damaged to the extent that it does not function or showing signs of severe leakage
41 occurrences · 1.9% of tests
- 07
Tyre tread depth not in accordance with the requirements
35 occurrences · 1.6% of tests
- 08
A tyre cords visible or damaged
31 occurrences · 1.4% of tests
- 09
A suspension pin, bush or joint excessively worn
30 occurrences · 1.4% of tests
- 10
A lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning
29 occurrences · 1.3% 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
£208–£605
If every one of this CL 500'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 CL 500?
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 CL 500 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.