Mercedes-Benz B-Class MOT pass rate: 74.9% (60,589 tests, 2025)

The Mercedes-Benz B-Class passed 74.9% of its 60,589 MOT tests in 2025 — 2.6 points below the UK average of 77.5%. The median tested example was 12 years old with 74,688 miles on the clock.

74.9%Pass rate (2025)

60,589MOT tests analysed

74,688 miMedian mileage at test

12 yrsMedian age at test

How the B-Class compares

Mercedes-Benz B-Class

74.9%

UK average (all Class 4 vehicles)

77.5% across 33.1 million tests

Mercedes-Benz average (all models)

80.7%

What fails most on the Mercedes-Benz B-Class

Across failed and rectified tests in 2025, these vehicle systems produced the most defects on the B-Class:

#	System	Defects recorded	Share
1	Suspension	9,367	26.3%
2	Lamps, reflectors and electrical equipment	6,999	19.6%
3	Brakes	6,268	17.6%
4	Tyres	5,431	15.2%
5	Body, chassis, structure	2,508	7.0%
6	Visibility	2,360	6.6%

Pre-MOT checklist for B-Class owners

Based on the failure profile above, ten minutes with a torch before your test removes the most likely fail items:

Bounce each corner and listen for clonks over speed bumps — suspension is this model’s (and the UK’s) top failure system
Walk round with all lights on: one blown bulb is the most avoidable fail there is
Feel for a spongy pedal or pulling to one side; check pad wear through the wheel spokes if visible
Check tread with the 20p test and inspect sidewalls for cracking — tyres close to the limit are the country’s most common advisory
Look underneath for corrosion around sills and subframes, especially on older cars

Check the engine before the tester does

A stored fault code with the engine light on is an automatic Major defect. Scan and clear resolved faults before booking.

Topdon OBD2 scannersTopdon diagnostic scanners with full-system readouts
XTOOL diagnostic toolsXTOOL code readers for petrol and diesel cars
Autel UK testersAutel professional-grade diagnostic testers

B-Class pass rate by registration year

Lower age-adjusted outliers to inspect carefully: 2007, 2008, 2011. Strongest age-adjusted years: 2012, 2013. Full ranking and method: Mercedes-Benz B-Class years to avoid.

Registration year	Tests	Pass rate	Vs same-age	Median mileage
2006	6,041	63.8%	-0.6 pts	98,886
2007	7,995	63.9%	-1.2 pts	99,321
2008	10,406	62.7%	-2.5 pts	97,458
2009	12,889	65.2%	-1.2 pts	92,433
2010	13,526	66.2%	-1.2 pts	85,871
2011	10,564	66.5%	-2.6 pts	80,290
2012	17,149	74.8%	+3.6 pts	80,882
2013	21,050	76.9%	+3.6 pts	74,321
2014	24,472	78.1%	+2.3 pts	68,341
2015	16,801	82.2%	+3.5 pts	59,568
2016	15,871	84.3%	+2.9 pts	50,762
2017	16,858	85.2%	+1.2 pts	44,116
2018	11,468	87.7%	+1.4 pts	34,166
2019	1,754	91.2%	+2.8 pts	26,476

Check a specific B-Class before you buy

Pass rates describe the model; they can’t tell you about the one car you’re looking at. Run its plate through our free MOT history check to see its personal record of failures, advisories and mileage readings.

Other Mercedes-Benz models

C78.2% pass rate · 343,551 tests A-Class77.8% pass rate · 232,671 tests E79.7% pass rate · 215,896 tests A89.1% pass rate · 93,733 tests Vito73.4% pass rate · 81,263 tests GLC87.2% pass rate · 65,847 tests GLA83.1% pass rate · 64,404 tests CLA82.7% pass rate · 62,279 tests

FAQs

What is the MOT pass rate for a Mercedes-Benz B-Class?

In 2025, 74.9% of 60,589 first MOT tests on the Mercedes-Benz B-Class were passes (UK average: 77.5%). Data: DVSA anonymised MOT results.

What does the B-Class fail its MOT on most?

The biggest defect group is suspension (26.3% of its recorded defects), followed by lamps, reflectors and electrical equipment.

Is the Mercedes-Benz B-Class reliable?

MOT pass rate is one lens on durability: at 74.9% it performs below the national average at a median age of 12 years and 74,688 miles. Always check the individual car's history too.

Source: DVSA Anonymised MOT tests and results, 2025 extract (Class 4 initial tests only; retests excluded). Contains public sector information licensed under the Open Government Licence v3.0. Figures rounded to one decimal place.