The picture
C30: a below-average pass rate worth digging into
Across 32,393 MOT tests, the C30 returns 68.5% first-time pass — well below the UK fleet average. The single most-logged Major fail is a number-plate lamp out. Worn suspension bushes and a broken or weak spring round out the top three. Average tested mileage sits at 100,188, 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 rear registration plate lamp or light source missing or inoperative in the case of multiple lamps or light sources
3,932 occurrences · 12.1% of tests
- 02
A suspension pin, bush or joint excessively worn
1,560 occurrences · 4.8% of tests
- 03
A spring or spring component fractured or seriously weakened
1,359 occurrences · 4.2% of tests
- 04
A lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning
1,329 occurrences · 4.1% of tests
- 05
A transmission shaft constant velocity joint boot missing or no longer prevents the ingress of dirt etc
1,134 occurrences · 3.5% of tests
- 06
A transmission shaft constant velocity joint boot severely deteriorated
1,124 occurrences · 3.5% of tests
- 07
Tyre tread depth not in accordance with the requirements
1,033 occurrences · 3.2% of tests
- 08
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
1,016 occurrences · 3.1% of tests
- 09
A tyre cords visible or damaged
1,003 occurrences · 3.1% of tests
- 10
A rear registration plate lamp or light source missing or inoperative in the case of a single lamp or all lamps
771 occurrences · 2.4% 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 3 failures
£168–£515
If every one of this C30'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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Build your own retest budget.
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.
Owner reports · Honest John
What owners actually report.
Verbatim faults logged by owners on honestjohn.co.uk over recent years. We didn't summarise — these are the words people typed in.
Where it falls short
One last point - if your circumstances change, make sure your inform your insurer, too. If your details don't match what an insurer has on record, that could lead to problems with claims and future renewals.
Buying or keeping a C30?
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 C30 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.