2012 Mercedes-Benz B-Class MOT pass rate: 74.8% (17,149 tests)

2012-registered Mercedes-Benz B-Classs passed 74.8% of 17,149 MOT tests in 2023–2025 — 3.6 points better than all UK cars registered in 2012 (71.2%). This is one of the strongest B-Class years in the age-adjusted MOT ranking, although the individual car still matters more.

74.8%Pass rate, 2012 cars

103.6Age-adjusted index (100 = average)

17,149Tests analysed

80,882 miMedian mileage at test

79.4% / 72.9%Petrol vs diesel pass rate

Is the 2012 B-Class getting worse?

Pass rate of 2012-registered cars across recent test years:

Test year	Pass rate
2023	75.5% +3.2 vs same-age
2024	74.6% +3.6 vs same-age
2025	74.3% +4.0 vs same-age

The raw rate normally falls as cars age. The “vs same-age” figure compares this cohort with all UK cars registered in the same year, so normal ageing is not mistaken for a bad model year.

What fails on a 2012 B-Class

#	System	Defects recorded	Share
1	Suspension	2,889	29.5%
2	Brakes	1,705	17.4%
3	Lamps, reflectors and electrical equipment	1,685	17.2%
4	Tyres	1,582	16.2%
5	Noise, emissions and leaks	510	5.2%
6	Visibility	461	4.7%

All B-Class years compared

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 (this page)	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

Weighing up which year to buy? See the full ranking: Mercedes-Benz B-Class years to avoid.

Buying a 2012 B-Class? Two checks first

Free MOT history checkThe exact car’s failures, advisories and mileage trail — sellers can’t edit it
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

FAQs

Is a 2012 Mercedes-Benz B-Class reliable?

2012-registered examples passed 74.8% of their MOT tests (17,149 tests, 2023–2025), +3.6 points versus all UK cars registered in the same year. At roughly 14 years old with a median 80,882 miles, condition now varies car by car — always check the individual MOT history.

What mileage is too high for a 2012 B-Class?

The median tested example shows 80,882 miles. Anything far beyond that isn't automatically bad — a motorway-mile car with consistent service records often beats a low-mileage school-run car — but price accordingly and scrutinise the mileage trail for gaps or drops.

Should I buy the petrol or diesel 2012 B-Class?

In this cohort petrols pass 79.4% of tests against 72.9% for diesels. Mileage and use can explain part of that gap, so treat it as a reason to inspect DPF and emissions history, not a fuel-type verdict.

Source: DVSA Anonymised MOT tests and results, 2023–2025 extracts (96 million Class 4 initial tests; retests excluded). Only vehicles old enough for a routine first MOT are included. Age-adjusted figures compare the model-year cohort with all vehicles of the same registration year tested in the same calendar year. Contains public sector information licensed under OGL v3.0.