The picture
Diablo: middle-of-the-pack on first-time pass
Across 474 MOT tests, the Diablo returns 74.7% first-time pass — below the UK fleet average. The single most-logged Major fail is a non-functioning shock absorber. A stop-lamp out and stop lamp(s) does not illuminate by the operation of both brake controls round out the top three. Average tested mileage sits at 8,950, 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 shock absorber not functioning or leaking severely
31 occurrences · 6.5% of tests
- 02
Stop lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning
12 occurrences · 2.5% of tests
- 03
A stop lamp(s) does not illuminate by the operation of both brake controls or remains on when the brakes are released
11 occurrences · 2.3% of tests
- 04
Steering head bearings have excessive wear or play
9 occurrences · 1.9% of tests
- 05
A rear registration plate lamp or light source missing or inoperative in the case of a single lamp or all lamps
9 occurrences · 1.9% of tests
- 06
The aim of a headlamp is not within limits laid down in the requirements
8 occurrences · 1.7% of tests
- 07
Exhaust system leaking or insecure
8 occurrences · 1.7% of tests
- 08
Brake lining or pad worn below 1.0mm
7 occurrences · 1.5% of tests
- 09
Rear registration plate lamp does not illuminate simultaneously with the position lamps
7 occurrences · 1.5% of tests
- 10
Tyre tread depth not in accordance with the requirements
7 occurrences · 1.5% 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
£114–£295
If every one of this Diablo'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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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 Diablo?
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 Diablo 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.