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Mercedes-Benz B-Class W246 (2012-2018) reliability

At a glance

Mercedes-Benz B-Class W246 built around 2018: fails its MOT less often than average

Mercedes-Benz B-Class W246 models built around 2018 fail their MOT less often than similar cars the same age.

Looking at a Mercedes-Benz B-Class W246?

Enter its number plate to see its full MOT history, risk rating and running costs.

Key figure

15% of MOT tests on Mercedes-Benz B-Class W246 models built around 2018 ended in a fail (retests included), against 22% for similar cars the same age.

Most common issue

The most common MOT issue on Mercedes-Benz B-Class W246 models built around 2018 involves the tyres.

Mercedes-Benz B-Class W246
No reliability rating: too close to call between ratings2012-2018MPVPETROL / DIESEL / ELECTRICITY

Based on 51,732 tests of B-Class models registered 2012-2018.

About 1 in 50 B-Class W246 MOTs (2.1%) failed and still hadn't passed 3 days later. That's for cars built around 2018 (7 years old), all fuels combined.

Based on 5,267 tests (DVSA MOT results, 2025). A fail that passed a retest within 3 days, even the same day, isn't counted. Nor is a fail with no later MOT on record.

About 1 in 20 B-Class W246 MOTs (5.5%) found at least one dangerous defect. These are cars built around 2018 (7 years old).

Based on 5,267 tests (DVSA MOT results, 2025). Dangerous is the most serious grade an MOT gives: a direct risk to road safety.

W246 fail rate by age

Below typicalAbove typicalHigh (28% or more)Highest fail rateUK average for cars this age
Age / builtFail rateMOT tests
6 yearsbuilt around 2019
1,70013.7%
7 yearsbuilt around 2018
5,26715.4%
8 yearsbuilt around 2017
6,95016.5%
9 yearsbuilt around 2016
6,54318.3%
10 yearsbuilt around 2015
8,27220.9%
11 yearsbuilt around 2014
10,54022.3%
12 yearsbuilt around 2013
8,48623.3%
13 yearsbuilt around 2012
3,97423.5%

Fail rate is the share of MOT tests that ended in a fail. Retests count as tests. How we count fail rates Build years are worked out from age, so they are approximate. Tests counted are 2025 MOTs. Highest fail rate at 13 years old.

How the B-Class W246 compares

At each age below, see how the B-Class W246 holds up against other cars the same age. The averages combine all fuel types.

Based on 182,274 tests across 17 Mercedes-Benz models, built around 2018 (7 years old).

Below typicalAbove typicalHigh (28% or more)Highest fail rateMercedes-Benz average
Age / builtFail rateMOT tests
6 yearsbuilt around 2019
1,70013.7%
7 yearsbuilt around 2018
5,26715.4%
8 yearsbuilt around 2017
6,95016.5%
9 yearsbuilt around 2016
6,54318.3%
10 yearsbuilt around 2015
8,27220.9%
11 yearsbuilt around 2014
10,54022.3%
12 yearsbuilt around 2013
8,48623.3%
13 yearsbuilt around 2012
3,97423.5%

Fail rate is the share of MOT tests that ended in a fail. Retests count as tests. How we count fail rates Build years are worked out from age, so they are approximate. Tests counted are 2025 MOTs.

What to check before viewing

The model's most common MOT issues, turned into things you can ask about or look for.

Brake pads

High priority

Ask when the pads were last replaced and check the warning-light history.

Brake discs

High priority

Ask for the date and mileage of the last disc replacement; visually check for a deep wear lip and rust pitting on each disc.

Tyres

Worth checking

Check tread depth across the full width on all four; uneven wear suggests alignment or suspension issues.

Vehicle-specific check

Worth checking

Check the car’s number plate on MOT Wise to see its own MOT history and any recalls for its build years.

Other people carriers to compare

Other people carriers, with each one's figures taken at the same age as the B-Class W246.

  1. 1

    Kia Venga

    Same body type, tested at the same age

    Fail rate
    11.8%
    Fail, no pass in 3 days
    0.7%
    Dangerous
    3.3%
    Still registered at 10 years
    96.8%

    Lower fail rate: 11.8%, against 15.4% for the Mercedes-Benz B-Class W246, both built around 2018.

    5,255 MOT tests on cars built around 2018

  2. 2

    Ford Tourneo

    Same body type, tested at the same age

    Fail rate
    21.4%
    Still registered at 10 years
    89.2%

    No clear edge over the Mercedes-Benz B-Class W246 on these figures.

    Some figures could not be compared for these two cars. So this comparison uses the fail rate and recalls only.

    3,550 MOT tests on cars built around 2018

  3. 3

    Vauxhall Zafira

    Same body type, tested at the same age

    Fail rate
    20.3%
    Still registered at 10 years
    89.7%

    No clear edge over the Mercedes-Benz B-Class W246 on these figures.

    Some figures could not be compared for these two cars. So this comparison uses the fail rate and recalls only.

    10,737 MOT tests on cars built around 2018

  4. 4

    Toyota Estima

    Same body type, tested at the same age

    Fail rate
    17.7%

    No clear edge over the Mercedes-Benz B-Class W246 on these figures.

    Some figures could not be compared for these two cars. So this comparison uses the fail rate and recalls only.

    1,057 MOT tests on cars built around 2018

Fail rate
= the share of MOT tests that ended in a fail. Retests count as tests.
Fail, no pass in 3 days
= the share of MOT tests that failed and still hadn't passed 3 days later. A fail that passed a retest within 3 days, even the same day, isn't counted.
Dangerous
= the share of MOT tests where the tester marked a fault as dangerous. It is against the law to drive the car until it is fixed.
Still registered at 10 years
= the share of cars still registered (taxed or declared off the road) 10 years after they were first registered.

How many are still registered

Not enough registration data to show this for the Mercedes-Benz B-Class.

The share still registered can reflect demand, the cost of repairs, exports, write-offs and how owners use the car. It isn't proof of how long the car lasts mechanically.

Recall context

65 recalls in all

33 of the 65 B-Class W246 recalls cover cars built in these years.

  • 6 Critical
  • 27 more

Top concerns

  • Electrical wiring in steering assembly may be insufficiently grounded
  • Steering components may be insufficiently grounded
  • Starting current limiter may overload

For the exact car, check GOV.UK's recall checker with the number plate.

Fail rate by engine size, built around 2018 (7 years old)

Engine sizes across all diesel B-Class tests (not specific to W246).

1.4 to 2.0 litres17.1%1,910 tests2.0 to 3.0 litres16.0%1,636 tests
How B-Class W246 cars have aged

How B-Class W246 cars have aged

How fail rates have changed as these cars got older. Each line follows cars first registered in about the same year across several years of MOT data. Not a prediction for any one car.

0%10%20%35791113Age at MOTBuilt around 2018, 3 years old at the time of MOT: 10.2% (3,359 tests, 2021 data)Built around 2018, 4 years old at the time of MOT: 10.5% (3,125 tests, 2022 data)Built around 2018, 5 years old at the time of MOT: 11.2% (2,981 tests, 2023 data)Built around 2018, 6 years old at the time of MOT: 12.6% (2,934 tests, 2024 data)Built around 2018, 7 years old at the time of MOT: 14.7% (2,900 tests, 2025 data)2018Built around 2017, 4 years old at the time of MOT: 9.7% (4,631 tests, 2021 data)Built around 2017, 5 years old at the time of MOT: 11.1% (4,499 tests, 2022 data)Built around 2017, 6 years old at the time of MOT: 14.2% (4,509 tests, 2023 data)Built around 2017, 7 years old at the time of MOT: 14.8% (4,463 tests, 2024 data)Built around 2017, 8 years old at the time of MOT: 16.5% (4,414 tests, 2025 data)2017Built around 2016, 5 years old at the time of MOT: 11.0% (4,060 tests, 2021 data)Built around 2016, 6 years old at the time of MOT: 12.9% (3,982 tests, 2022 data)Built around 2016, 7 years old at the time of MOT: 14.7% (3,970 tests, 2023 data)Built around 2016, 8 years old at the time of MOT: 16.8% (3,968 tests, 2024 data)Built around 2016, 9 years old at the time of MOT: 17.9% (3,926 tests, 2025 data)2016Built around 2015, 6 years old at the time of MOT: 14.2% (4,384 tests, 2021 data)Built around 2015, 7 years old at the time of MOT: 15.4% (4,358 tests, 2022 data)Built around 2015, 8 years old at the time of MOT: 17.1% (4,368 tests, 2023 data)Built around 2015, 9 years old at the time of MOT: 18.6% (4,331 tests, 2024 data)Built around 2015, 10 years old at the time of MOT: 19.3% (4,333 tests, 2025 data)2015Built around 2014, 7 years old at the time of MOT: 16.6% (6,698 tests, 2021 data)Built around 2014, 8 years old at the time of MOT: 17.4% (6,560 tests, 2022 data)Built around 2014, 9 years old at the time of MOT: 20.4% (6,710 tests, 2023 data)Built around 2014, 10 years old at the time of MOT: 21.0% (6,620 tests, 2024 data)Built around 2014, 11 years old at the time of MOT: 21.9% (6,562 tests, 2025 data)2014Built around 2013, 8 years old at the time of MOT: 17.7% (5,341 tests, 2021 data)Built around 2013, 9 years old at the time of MOT: 19.5% (5,304 tests, 2022 data)Built around 2013, 10 years old at the time of MOT: 21.0% (5,193 tests, 2023 data)Built around 2013, 11 years old at the time of MOT: 22.4% (5,157 tests, 2024 data)Built around 2013, 12 years old at the time of MOT: 22.6% (5,000 tests, 2025 data)2013Built around 2012, 9 years old at the time of MOT: 20.0% (4,327 tests, 2021 data)Built around 2012, 10 years old at the time of MOT: 21.2% (4,247 tests, 2022 data)Built around 2012, 11 years old at the time of MOT: 22.6% (4,212 tests, 2023 data)Built around 2012, 12 years old at the time of MOT: 23.3% (4,091 tests, 2024 data)Built around 2012, 13 years old at the time of MOT: 23.5% (3,974 tests, 2025 data)2012
First registered around 2018First registered around 2017First registered around 2016First registered around 2015
W246 variants compared

B-Class W246 variants built around 2018

The fail rate for each B-Class W246 variant, grouped by fuel. Each row counts fails per MOT test, the same way as the main fail rate chart.

Diesel

  • B-CLASS16.6%3,523 tests

Petrol

  • B-CLASS12.9%1,711 tests
All generations of this modelPlenty of data

Most common issues on Mercedes-Benz B-Class models of this age

This list covers every Mercedes-Benz B-Class built around 2018, whichever generation it is. We don't have a defect list for the W246 on its own.

Most common advisories and fails

In order of the share of MOT tests that recorded each one

  1. 1
    Advisory

    Tyre slightly damaged, cracking or perishing

    14.7%
    Advisory: 922Fail: 211 (19% of the times it was found)
  2. 2
    Advisory

    Tyre worn close to the legal limit or worn on the edge

    14.2%
    Advisory: 1,018Fail: 57 (5% of the times it was found)
  3. 3
    Advisory

    Brake pads wearing thin

    10.3%
    Advisory: 587Fail: 62 (10% of the times it was found)
  4. 4
    Advisory

    Brake disc worn, pitted or scored, but not seriously weakened

    5.5%
    Advisory: 405Fail: 3 (1% of the times it was found)
  5. 5
    Advisory

    Tyre has a cut that does not reach the ply or cords

    4.8%
    Advisory: 210Fail: 104 (33% of the times it was found)

Based on 5,267 tests

Looking at a Mercedes-Benz B-Class W246?

Enter its number plate to see its full MOT history, risk rating and running costs.

Frequently asked questions

Built around 2018 (7 years old), the Mercedes-Benz B-Class W246 (2012-2018) fails MOTs at about the rate typical for this age. This is based on 5,267 7-year-old MOT tests from DVSA data. Each retest counts as a test.

*The build year is worked out from the date a car was first used on UK roads. For most cars this matches when it was registered, but imports may differ by a few months.

Data sourced from DVSA MOT History API. From 51,732 MOT tests on Mercedes-Benz B-Class models first registered between 2012-2018. These figures are a guide, not a guarantee.