Mercedes Benz
11,757 MOT tests analysed. sits above the UK fleet average — here's where Xs pass, fail, and end up on the retest sheet.
That's 8.3 points above the UK fleet average across our 1,984 tracked models — a confident result.
Pass
85.8%
Pass-after-fix
2.9%
Fail
10.4%
Avg miles
60,988
Pass + Pass-after-fix + Fail = 100%
Some examples of this model are borderline — a small number of diesels were certified Euro 6 before September 2015. Check your registration on the government's ULEZ checker to be certain. Daily charges if driven in the zone: London £12.50 · Birmingham £8.00 · Bristol £9.00 .
Performance by cohort
2 year bands · 11,756 tests
Pass rate is broadly flat across the cohorts — new and old X examples track each other at the test bay.
Pass
85.8%
Fail
10.9%
PRS
2.6%
Avg mileage at test
74,910 mi
Pass
85.8%
Fail
10.4%
PRS
3.0%
Avg mileage at test
59,019 mi
Cohort = vehicle's first-registration year band. Same model, different generations of build.
The picture
Across 4,595 MOT tests, the X returns 81.0% first-time pass — above the UK fleet average. The single most-logged Major fail is windscreen damage. A number-plate lamp out and brake pads worn below 1.5 mm round out the top three. Average tested mileage sits at 52,362, 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 →
28–46
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A rear registration plate lamp or light source missing or inoperative in the case of multiple lamps or light sources
315 occurrences · 2.7% of tests
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
260 occurrences · 2.2% of tests
An SRS malfunction indicator lamp (MIL) indicates a system malfunction
181 occurrences · 1.5% of tests
a brake lining or pad worn below 1.5mm
170 occurrences · 1.4% of tests
Engine MIL illuminated indicating a malfunction
151 occurrences · 1.3% of tests
Parking brake efficiency below minimum requirement
116 occurrences · 1.0% of tests
Wiper blade defective
115 occurrences · 1.0% of tests
Tyre tread depth not in accordance with the requirements
113 occurrences · 1.0% of tests
Wiper blade missing or obviously not clearing the windscreen
113 occurrences · 1.0% of tests
A suspension joint dust cover severely deteriorated
107 occurrences · 0.9% 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 2 failures
£88–£195
If every one of this X'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 →
Try the calculator
Build your own retest budget.
Year-band analysis
First-time MOT pass rate split by registration band. Pass rates barely move across bands here, so the year you buy Mercedes Benz X makes little measurable difference to MOT outcomes.
Best band to buy
85.8%
Pre-2018 registration
the older band (pre-2018) climbs to 85.8% — a 0.0-point improvement. Failures here are mostly wear items: inoperative in the case of multiple lamps…, damaged but not adversely affecting driver's view — the structural issues that drag down older examples don't appear in the top-10 for this band.
Band to be cautious about
85.8%
2018–2020 registration
On the 2018–2020 band, the data shows a 85.8% pass rate against a fleet average of 85.8% on the newer band. The main culprits logged at test: inoperative in the case of multiple lamps…, damaged but not adversely affecting driver's view, and less than 1.5 mm thick. Average mileage on test for this band is 59,019 miles — high-mileage wear items are a recurring theme.
Best band to buy: pre-2018 (85.8% first-time pass). Worst band to avoid: 2018-2020 (85.8% pass). That's a 0.0-point spread across 10,301 older tests and 1,455 newer ones — year of build makes a material difference on this model.
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.
Item 01 · Amazon UK
H7 / W21W bulb pack
A spare-bulb kit lives in the boot. Test morning is not the time to find your stop-lamp's gone.
Search Amazon UK
Item 02 · Amazon UK
Brake pad measurement gauge
Testers fail pads under 1.5mm. A wear gauge tells you if you've got two months left or two weeks.
Search Amazon UK
My Motor World · affiliate
Affiliate links — small commission, no extra cost to you.
Click Mechanic · affiliate
Affiliate links — small commission, no extra cost to you.
Mobile mechanic · UK-wide
Book a mechanic at your door.
Fixed-price quotes upfront. No garage needed. Click Mechanic sends a vetted local mechanic to you — home, work, or roadside.
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 an X 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.
