2021 Mercedes-Benz B: MOT pass rate and reliability
93.6% of 2021 Mercedes-Benz Bs pass the MOT first time, measured across 1,339 DVSA tests on that model year alone. The average one had covered 21,179 miles.
How the 2021 compares
- Against all Mercedes-Benz Bs (92.2%, 7,891 tests): +1.4 points
- Against all 2021 cars (90%): +3.6 points
- National first-time pass rate, all cars and years: 77%
Every Mercedes-Benz B model year
Pass rates fall as cars age, so the only fair comparison for a 2021 car is other cars of the same age. The full run for the Mercedes-Benz B:
| Year | Pass rate | Tests | Avg mileage |
|---|---|---|---|
| 2019 | 91.4% | 3,602 | 29,755 |
| 2020 | 93% | 2,791 | 25,514 |
| 2021 | 93.6% | 1,339 | 21,179 |
What this means if you are buying a 2021 B
The 2021 sits close to the Mercedes-Benz B average, so there is no strong model-year signal either way. Judge the individual car on its own history. Check the exact car with the free MOT history checker before you buy, and run its VIN and mileage through our free VIN decoder and clocking check.
What a 5-year-old car fails on
A 2021 car is 5 years old now, and age drives the failure mix more than the badge does. Across all cars tested, these are the categories that actually cause failures:
- Lights and electrical: 10.36% of all cars tested
- Suspension: 8.65% of all cars tested
- Tyres: 6.23% of all cars tested
- Brakes: 6.1% of all cars tested
- Visibility: wipers, washers, glass: 4.65% of all cars tested
- Body, chassis and structure: 3.18% of all cars tested
That is low mileage, which usually means light urban use. Short journeys are harder on batteries, brakes and exhausts than motorway miles, so do not assume low miles means low wear. On a 2021 Mercedes-Benz B the average at test was 21,179 miles, so treat anything far above that as a car that has worked harder than its peers, and anything far below as one worth checking for the faults that come from standing still.
2021 is the strongest year on record for this model at 93.6%, ahead of every other year we hold data for.
Nearby model years
- 2019 Mercedes-Benz B - 91.4%
- 2020 Mercedes-Benz B - 93%