Pass rate
89.1%
Above average — 1.2 pts ahead of the 87.9% that cars this age and mileage manage.
Across 12,760 recorded tests.
Typical repair bill £30–£73
2018 Mercedes-Benz B-Class MOT pass rate
- 2018
- 2 trims combined
- typical 34,861 mi
Most common fault
Tyres
45.4% of faults · 19.8% nationally
mostly tread below the limit, cuts and sidewall bulges.
Which year to buy
- Best 2019 91.9% pass
- Avoid 2008 71.8% pass
Across the 15 years on record, a spread of 20.1 points. See every year →
- First-attempt pass
- 87.8%
- Typical mileage
- 35k mi
The 2018 Mercedes-Benz B-Class MOT pass rate is 89.1% of its MOT tests — 1.2 points ahead of what its age and mileage predict. Tyres is the biggest single reason it fails, at 45.4% of what testers record.
Check your postcode
MOT pass rates are national — type your postcode to see how Mercedes-Benz B-Class does in your corner of the country.
Expert verdict
Tyres: 2.3× the national share
Tyres make up 45.4% of everything recorded on the 2018 Mercedes-Benz B-Class, against 19.8% nationally — 25.6 points above. Check all four tyres yourself, including the inner shoulders, and look at the date stamp — a tyre can pass on tread and still be six years old.
Written from this page's own figures: fault shares against the national composition, the like-for-like pass rate, and the priced repair list. How these are worked out
Watching a Mercedes-Benz B-Class? Get an email when these numbers change .
Every Mercedes-Benz B-Class first registered in 2018 is combined here — 2 trim and body variants in total — so the sample is as large as the DVSA data allows.
How does the 2018 Mercedes-Benz B-Class compare?
Cars of this age and mileage average 87.9%, so this figure is 1.2 points ahead of what its age and mileage predict. On a first attempt, before any retests, the figure drops to 87.8%. The median 2018 Mercedes-Benz B-Class in this dataset had covered 34,861 mi.
The most common fuel recorded here is Diesel — 52% of tests, with a 87.7% pass rate. Pass rates also shift with the test month: tests recorded October–March passed 89.3% of the time, April–September 88.9%.
The single most recorded failure item is "Registration plate lamp(s) inoperative in the case of multiple lamps or light sources", noted on 2.17% of tests.
- 12,760 recorded tests behind this page.
- 89.1% overall pass rate, 87.8% on a first attempt.
- Across every year of the Mercedes-Benz B-Class, the average is 79.9% — best year 2019 (91.9%), worst 2008 (71.8%).
Figures count every completed test on this vehicle-year in the dataset, including retests. See methodology for the exact definition.
This page's data
- Tests analysed
- 12,760
- Typical mileage (median)
- 34,861 mi
- Make and model
- Mercedes-Benz B-Class
- Updated
- 2026-11-05
Source: DVSA anonymised MOT test data (2023–2025), OGL v3.0.
Top part to budget for
Number Plate Lamp
Usually a DIY or independent-garage job.
Does mileage affect the B-Class MOT pass rate?
Pass rate by odometer reading. Bar lengths start at 70% so small gaps stay visible.
Fuel type and reliability
Pass rate by fuel type. Diesel is the most common here (52% of tests).
Regional pass rates for the B-Class
| Region | Tests | Pass rate |
|---|---|---|
| South East | 3,317 | 89.6% |
| South West | 1,487 | 88.7% |
| East of England | 1,375 | 88.3% |
| North West | 1,299 | 88.6% |
| London | 1,116 | 90.1% |
| West Midlands | 1,003 | 91.4% |
| Yorkshire | 821 | 87.8% |
| East Midlands | 771 | 88.5% |
| Scotland | 726 | 86.0% |
| Wales | 497 | 90.5% |
| North East | 348 | 88.2% |
Regions come from the postcode area recorded at the test station. Areas on region borders are assigned to the region with the majority of their population.
What fails a 2018 B-Class
Everything a tester recorded on this vehicle, grouped into the inspection sections that produced it. The notch on each bar is the national share, so you can see at a glance whether this car is unusual or just ordinary.
A test can record several items, so these percentages do not add up to 100%. The exact strings, with prices, are in the full DVSA record at the bottom of this page.
Before your test
Three checks worth doing on a 2018 B-Class
These are not generic tips — they are the faults recorded most often on this exact model, rewritten as things you can check yourself. All three take about ten minutes and cost nothing.
-
Check the lights 2.2% of tests
“registration plate lamp(s) inoperative in the case of multiple lamps or light sources”
Switch everything on and walk round the car: both headlamps on dip and main, every indicator, both brake lights, reverse, fog and the two number-plate lamps. A bulb is a few pounds and a five-minute job.
-
Check the windscreen 1.8% of tests
“windscreen damaged”
Check the driver’s side of the screen within the swept area for chips and cracks; anything larger than 10mm in the driver’s central view is a fail. Most chips can be resin-repaired for far less than a new screen.
-
Check the wipers and washers 1.0% of tests
“wipers blade defective”
Run the wipers with the screen wet: they should clear it in one sweep without smearing or juddering. Top the washer bottle up and check both jets hit the screen.
Shares are the proportion of tests on this vehicle that recorded the item, so they overlap: one test can record several.
What it costs to get a 2018 B-Class through its MOT
Across the 10 items that are recorded most often on this model, the average repair comes to £30–£73 — and 45% of those repairs are parts that cost under £30.
- Average repair across the 10 common items
- £30–£73
- Cheapest common item: registration plate lamp(s) inoperative in the…
- £5–£20
- Dearest common item: windscreen damaged
- £80–£200
- Common items a careful owner can do at home
- 90%
- Repairs that still cost under £30
- 45%
Estimates from typical UK parts prices, weighted by how often each item appears in 12,760 MOT tests on this vehicle. They exclude diagnostics, retest fees and garage labour where the part is a DIY fit, and they are not figures from the DVSA dataset. Older and higher-mileage examples cost more than the average. How these estimates are built → · All MOT repair costs → · Cheapest cars to put through a test →
Every year of the B-Class, side by side
15 model years on record, from 2005 to 2019. Across them the pass rate runs from 71.8% to 91.9% — a spread of 20.1 points. The bar under each year is the item that failed it most often.
- 2005 71.9% joints constant velocity boot…
- 2006 72.3% joints constant velocity boot…
- 2007 72.3% joints constant velocity boot…
- 2008 71.8% joints constant velocity boot…
- 2009 73.4% joints constant velocity boot…
- 2010 74.0% joints constant velocity boot…
- 2011 74.4% side repeaters not working
- 2012 79.5% linkage ball joint dust cover…
- 2013 81.0% linkage ball joint dust cover…
- 2014 81.8% coil spring fractured or broken
- 2015 84.7% coil spring fractured or broken
- 2016 86.3% registration plate lamp(s)…
- 2017 87.1% registration plate lamp(s)…
- 2018 89.1%registration plate lamp(s)…
- 2019 91.9% has a cut in excess of the…
Colour is the pass rate on a fixed scale, so a block means the same thing on any model. Each year links to its own page with the full fault breakdown.
Compare the 2018 Mercedes-Benz B-Class with another year
The raw pass rate mostly measures age. The year comparison adds the like-for-like figure, the mileage bands and the repair bill.
Other 2018 cars with a similar record
- Jaguar F-Pace 89.1%
- BMW X5 89.1%
- BMW 318 89.1%
- BMW 430 89.1%
- Subaru Forester 89.1%
- Toyota Verso 89.1%
Closest pass rates among 2018 cars with at least 2,000 tests, so a small sample cannot flatter itself into the list. See the full rankings: best and worst MOT pass rates.
The full DVSA record for the 2018 Mercedes-Benz B-Class 10 failure items · 6 advisories · 10 inspection categories · mileage brackets · all of it in the page, none of it above the fold
Every inspection category
Shares of the 9,426 individual items recorded on this vehicle, and the same share across all cars nationally. A single test can record several items, so a row is not a percentage of tests.
| Category | Items | This car | Nationally | Difference |
|---|---|---|---|---|
| Tyres | 4,307 | 45.40% | 19.76% | +25.64 |
| Brakes | 2,106 | 22.20% | 20.89% | +1.31 |
| Lamps, reflectors and electrical equipment | 781 | 8.20% | 12.21% | −4.01 |
| Non-component advisories | 662 | 7.00% | 4.18% | +2.82 |
| Visibility | 589 | 6.20% | 4.97% | +1.23 |
| Suspension | 350 | 3.70% | 20.98% | −17.28 |
| Identification of the vehicle | 253 | 2.70% | 1.76% | +0.94 |
| Road Wheels | 206 | 2.20% | 0.75% | +1.45 |
| Noise, emissions and leaks | 119 | 1.30% | 5.52% | −4.22 |
| Steering | 53 | 0.60% | 2.57% | −1.97 |
The exact failure items, in the tester's words
| Recorded item | Severity | Tests | Est. cost |
|---|---|---|---|
| Registration plate lamp(s) inoperative in the case of multiple lamps or light sources Lamps, reflectors and electrical equipment | Minor | 2.2% | £5–20 |
| Has a cut in excess of the requirements deep enough to reach the ply or cords Tyres | Major | 1.8% | £45–95 |
| Windscreen damaged but not adversely affecting driver's view Visibility | Minor | 1.8% | £80–200 |
| Registration plate lamp(s) inoperative in the case of a single lamp or all lamps Lamps, reflectors and electrical equipment | Major | 1.7% | £5–20 |
| Wipers blade defective Visibility | Minor | 0.98% | £8–22 |
| Has ply or cords exposed Tyres | Major | 0.95% | £45–95 |
| Coil spring fractured or broken Suspension | Major | 0.78% | £25–65 |
| Has a bulge, caused by separation or partial failure of its structure Tyres | Major | 0.64% | £45–95 |
| Brake pads less than 1.5 mm thick Brakes | Major | 0.56% | £18–45 |
| Wipers does not clear the windscreen effectively Visibility | Major | 0.49% | £8–22 |
Severity is as recorded: Major and Dangerous fail the test outright; Minor and Advisory do not. Costs are estimates from typical UK parts prices — see how they are built.
What testers noted without failing the car
Advisories are the early warnings — the same parts a year or two before they fail. Reading them is how you tell a car that has been maintained from one that has been patched.
| Recorded item | Severity | Tests | Est. cost |
|---|---|---|---|
| Tread depth below requirements of 1.6mm Tyres | Advisory | 11.1% | £45–95 |
| Has a tear, caused by separation or partial failure of its structure Tyres | Advisory | 10.7% | £45–95 |
| Brake pads less than 1.5 mm thick Brakes | Advisory | 7.7% | £18–45 |
| Brake discs in such a condition that it is seriously weakened Brakes | Advisory | 3.4% | £45–110 |
| Has a cut in excess of the requirements deep enough to reach the ply or cords Tyres | Advisory | 3.3% | £45–95 |
| Brake discs significantly and obviously worn Brakes | Advisory | 3.0% | £45–110 |
Pass rate by mileage
| Mileage | Tests | Pass rate | Median odometer |
|---|---|---|---|
| 0-30k | 4,975 | 92.0% | 20,790 mi |
| 30-60k | 6,123 | 88.4% | 42,129 mi |
| 60-90k | 1,347 | 83.8% | 70,930 mi |
| 90-120k | 224 | 78.1% | 99,814 mi |
| 120k+ | 88 | 80.7% | 151,010 mi |
Source: 12,760 recorded tests on this vehicle-year. Every row above is recomputed from the same DVSA extract as the rest of the page — see the methodology.
2018 B-Class MOT questions
What is the MOT pass rate for a 2018 Mercedes-Benz B-Class?
89.1% of the 12,760 2018 Mercedes-Benz B-Class tests in this dataset passed, against a national average of 87.9% for cars first used in 2018. First-attempt pass rate: 87.8%.
What are the most common MOT failures on a 2018 Mercedes-Benz B-Class?
The three most recorded items are registration plate lamp(s) inoperative in the case of multiple lamps or light sources (2.17%), has a cut in excess of the requirements deep enough to reach the ply or cords (1.77%), windscreen damaged but not adversely affecting driver's view (1.76%). Percentages are the share of tests on this vehicle that recorded the item.
Does mileage affect the 2018 Mercedes-Benz B-Class MOT pass rate?
Yes. Cars under 30,000 miles passed 92.0% of the time, falling to 80.7% for those over 120,000 miles. The median 2018 Mercedes-Benz B-Class in this dataset had covered 34,861 mi.
Which fuel type is most reliable for a 2018 Mercedes-Benz B-Class?
Diesel: 87.7% pass rate across 6,587 tests. Petrol: 90.5% pass rate across 6,169 tests. Shares are of the tests on this vehicle that recorded each fuel type.
Does the season affect the 2018 Mercedes-Benz B-Class MOT pass rate?
Tests recorded in the winter months (October–March) passed 89.3% of the time; summer months (April–September) passed 88.9%. Brakes, tyres and lights are tested harder in bad weather, but the difference is small on most models.