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MOT fail rates

Mercedes-Benz B-Class MOT fail rate by age

How often the Mercedes-Benz B-Class fails its MOT at each age, compared with all cars of the same age, and what it fails on. From 290,232 DVSA MOT tests taken 2022 to 2025.

MOT data updated

At 10 years, the most tested age

MOT fail rate at age 10 (n=27,268)25.2%
All cars at 10 years (n=9,049,507)30.3%
Median mileage at test68,522
All cars, median mileage75,043

109 of 309 model groups with enough tests fail less often at 10 years.

What stands out

  • At 3 years the Mercedes-Benz B-Class fails 8.7% of MOTs (10,576 tests), 3.4 points below the 12.1% for all cars that age. At 19 years it fails 43.0% (2,045 tests), about the same as the 43.2% average.
  • It moves from below to above the all-car rate between 13 and 14 years.
  • Its most common structural or mechanical fail item at 10 years: Coil spring broken, at 3.8 per 100 MOTs.

MOT fail rate by age

3 years 19 years 48.4%

Solid line: this model. Dashed line: all cars at the same age.

Mercedes-Benz B-Class: share of MOT tests that failed, by age, against all cars. Ages with fewer than 1,000 tests are not shown.
AgeMOT fail rateTests (n)All carsDifferenceMedian mileage
3 years8.7%10,57612.1%−3.4 pts17,067 miles
4 years9.9%13,19013.4%−3.5 pts22,451 miles
5 years11.7%16,98815.3%−3.6 pts29,094 miles
6 years13.9%19,50817.8%−3.9 pts36,168 miles
7 years17.1%20,86420.6%−3.5 pts44,578 miles
8 years19.9%25,18923.8%−3.8 pts53,293 miles
9 years22.8%26,79627.1%−4.4 pts60,874 miles
10 years25.2%27,26830.3%−5.1 pts68,522 miles
11 years29.7%25,35033.3%−3.6 pts74,063 miles
12 years32.6%21,87136.0%−3.4 pts78,852 miles
13 years36.6%19,37938.3%−1.6 pts83,751 miles
14 years41.6%17,22940.3%+1.3 pts87,930 miles
15 years42.6%16,31841.6%+1.0 pts92,743 miles
16 years43.4%13,76642.6%+0.8 pts97,188 miles
17 years44.0%8,98643.1%+0.9 pts98,953 miles
18 years43.8%4,90943.3%+0.5 pts98,958 miles
19 years43.0%2,04543.2%−0.2 pts99,055 miles

Most common fail items at 10 years

Split into structural or mechanical items and wear items. Wear items (tyres, brake pads, wipers, bulbs) say more about upkeep than about the design.

Structural and mechanical

Fail itemPer 100 MOTs
Coil spring broken Major3.8
Linkage ball joint dust cover: ball joint dust cover no longer prevents the ingress of dirt Major3.7
Airbag (SRS) warning light on Major1.5

Out of 27,268 MOTs. A test with two faults counts twice.

Wear and upkeep

Fail itemPer 100 MOTs
Registration plate lamp(s): inoperative in the case of a single lamp or all lamps Major3.4
Tyre tread below 1.6 mm Dangerous2.2
Tyre with cords exposed Dangerous2.2
Tyre condition: has a cut in excess of the requirements deep enough to reach the ply or cords Major2.2
Brake pads under 1.5 mm Dangerous2
Headlamp aim: too low Major1.4
Brake light not working Major1.4

Out of 27,268 MOTs. A test with two faults counts twice.

Other models at 10 years

ModelMOT fail rateTests (n)All cars
Mercedes-Benz C-Class25.2%115,49830.3%
Mercedes-Benz E-Class24.3%76,96630.3%
Mercedes-Benz A-Class28.5%72,28730.3%

MOT fail rate by first-use year

Each year has its own page: the fail rate for cars first used that year at each MOT from 2022 to 2025 with at least 1,000 tests, the most common faults at that age, and the car tax and ULEZ rules for that year.

First-use year data updated .

Latest MOT age with at least 1,000 tests for each first-use year.
First usedAge at testMOT fail rateTests (n)All cars
200619 years in 202543.1%1,63243.2%
200718 years in 202543.7%2,26643.3%
200817 years in 202544.5%3,09943.1%
200916 years in 202541.4%4,06142.6%
201015 years in 202541.5%4,36341.6%
201114 years in 202540.9%3,41640.3%
201213 years in 202530.6%5,78538.3%
201312 years in 202528.8%7,03036.0%
201411 years in 202528.1%8,25633.3%
201510 years in 202523.3%5,69530.3%
20169 years in 202520.8%5,38327.1%
20178 years in 202519.5%5,71923.8%
20187 years in 202516.4%3,99820.6%
20196 years in 202510.8%4,31817.8%
20205 years in 20259.9%2,93415.3%
20214 years in 20258.2%1,82013.4%

More on the Mercedes-Benz B-Class

Read this with care. A fail rate is not a measure of build quality. How far cars are driven, how they are used and how well owners maintain them all change it, and wear items such as tyres and brake pads are common fails. Compare a model only with cars of the same age. Methodology and limits.

Looking at one Mercedes-Benz B-Class?

These are figures for the model, not for one car. The VetTheCar Buying Report looks at a single car: its MOT tests, defects, advisories and mileage readings.

See an example report Browse the car tools

Source

Contains public sector information licensed under the Open Government Licence v3.0. Source: DVSA anonymised MOT test data, class 4 normal MOT tests, 2022 to 2025. MOT data updated 22 September 2026.

Not affiliated with or endorsed by DVSA. How we calculate these figures · Data sources