Photo: Alexander Migl, CC BY-SA 4.0
Mercedes Benz
1,524 MOT tests analysed. sits above the UK fleet average — here's where S 350 L Grand ED Executive D As pass, fail, and end up on the retest sheet.
That's 15.3 points above the UK fleet average across our 1,984 tracked models — a confident result.
Pass
92.8%
Pass-after-fix
0.5%
Fail
6.2%
Avg miles
51,049
Pass + Pass-after-fix + Fail = 100%
Diesel cars registered from September 2015 generally meet Euro 6 — compliant in London ULEZ, Birmingham CAZ, Bristol CAZ, and Glasgow LEZ.
Performance by cohort
2 year bands · 1,524 tests
Pass rate climbs 1.8 points across the cohorts — newer S 350 L Grand ED Executive D A examples clear the test more reliably than the early cars.
Pass
92.5%
Fail
6.5%
PRS
0.4%
Avg mileage at test
53,896 mi
Pass
94.3%
Fail
4.7%
PRS
1.0%
Avg mileage at test
39,306 mi
Cohort = vehicle's first-registration year band. Same model, different generations of build.
The picture
Across 491 MOT tests, the S 350 L Grand Ed Executive D A returns 90.8% first-time pass — comfortably ahead of the UK fleet average. The single most-logged Major fail is a seriously damaged tyre. Tyre tread under the limit and windscreen damage round out the top three. Average tested mileage sits at 39,791, 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.
ABI Insurance Group
A high-group car — insurance costs will be significantly above average. Lower groups cost less to insure; UK fleet average is around Group 22.
Source: ABI Group Rating Panel · administered by Thatcham Research · groups cover standard variants; performance trims may sit higher. Browse all insurance groups →
42–50
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Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
32 occurrences · 2.1% of tests
Tyre tread depth not in accordance with the requirements
22 occurrences · 1.4% of tests
A tyre seriously damaged
12 occurrences · 0.8% of tests
A tyre cords visible or damaged
12 occurrences · 0.8% of tests
A suspension pin, bush or joint excessively worn
7 occurrences · 0.5% of tests
a brake lining or pad worn below 1.5mm
7 occurrences · 0.5% of tests
Tyres on the same axle or on twin wheels are different sizes
6 occurrences · 0.4% of tests
A tyre fouling a part of the vehicle
4 occurrences · 0.3% of tests
A front or rear fog lamp with a multiple light source up to 1/2 not functioning
3 occurrences · 0.2% of tests
A tyre seriously damaged
3 occurrences · 0.2% 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
£200–£430
If every one of this S 350 L Grand ED Executive D A'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.
Year-band analysis
First-time MOT pass rate split by registration band. A 1.8-point gap between bands is modest — the year you buy Mercedes Benz S 350 L Grand ED Executive D A makes a small but real difference to MOT outcomes.
Best band to buy
94.3%
2021+ registration
the 2021-on band climbs to 94.3% — a 1.8-point improvement. Tests in this band average 39,306 miles — roughly 15K miles fewer on the clock than the older band. Failures here are mostly wear items: has a cut in excess of the…, tread depth below requirements of 1.6mm — the structural issues that drag down older examples don't appear in the top-10 for this band. Post-2020 examples are early in their MOT life and generally show the cleanest records.
Band to be cautious about
92.5%
2018–2020 registration
On the 2018–2020 band, the data shows a 92.5% pass rate against a fleet average of 94.3% on the newer band. The main culprits logged at test: damaged but not adversely affecting driver's view, tread depth below requirements of 1.6mm, and has ply or cords exposed. Average mileage on test for this band is 53,896 miles — high-mileage wear items are a recurring theme.
Best band to buy: 2021+ (94.3% first-time pass). Worst band to avoid: 2018-2020 (92.5% pass). That's a 1.8-point spread across 1,228 older tests and 296 newer ones — year of build makes a material difference on this model.
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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 S 350 L Grand ED Executive D A 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.
