The picture
S4: above-average pass rates, with caveats
Across 1,294 MOT tests, the S4 returns 80.6% first-time pass — above the UK fleet average. The single most-logged Major fail is a torn suspension dust cover. A split CV-joint boot and a number-plate lamp out round out the top three. Average tested mileage sits at 97,662, 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 joint dust cover severely deteriorated
78 occurrences · 6.0% of tests
- 02
A transmission shaft constant velocity joint boot severely deteriorated
46 occurrences · 3.6% of tests
- 03
A rear registration plate lamp or light source missing or inoperative in the case of multiple lamps or light sources
45 occurrences · 3.5% of tests
- 04
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
44 occurrences · 3.4% of tests
- 05
A spring or spring component fractured or seriously weakened
30 occurrences · 2.3% of tests
- 06
A tyre cords visible or damaged
26 occurrences · 2.0% of tests
- 07
Tyre tread depth not in accordance with the requirements
26 occurrences · 2.0% of tests
- 08
A suspension pin, bush or joint excessively worn
25 occurrences · 1.9% of tests
- 09
A transmission shaft constant velocity joint boot missing or no longer prevents the ingress of dirt etc
25 occurrences · 1.9% of tests
- 10
A tyre seriously damaged
21 occurrences · 1.6% 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 S4'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 S4?
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 S4 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.