2021 · 3 years old at test · Diesel mostly

2021 Mercedes-Benz S-Class MOT pass rate and common faults

655 MOT tests in 2024. 92.4% passed first time, compared with 87.6% for all cars the same age.

105Above average
Passed first time92.4%
Failed or needed repairs7.6%
Typical mileage at test30,000

Most common reasons for failing

Share of all 655 tests where this item caused a failure.

  1. Tyres - condition: has a bulge, caused by separation or partial failure of its structure2.3%
    21 marked dangerous
  2. Tyres - condition: has a cut in excess of the requirements deep enough to reach the ply or cords2.0%
  3. Tyres - condition: has ply or cords exposed0.8%
    7 marked dangerous
  4. Headlamp aim: too high0.6%
  5. Brake pads: less than 1.5 mm thick0.6%
    6 marked dangerous
  6. Tyres - condition: has a lump, caused by separation or partial failure of its structure0.3%
    2 marked dangerous
  7. Headlamp aim: too low0.3%
  8. Wipers: does not clear the windscreen effectively0.3%
  9. Malfunction indicator lamp: inoperative or indicates a malfunction0.3%
  10. Tread depth below requirements of 1.6mm0.3%
    5 marked dangerous

Problem areas

Failure items found per 100 tests, by part of the car.

  1. Tyres6.0%
  2. Lights & electrics1.1%
  3. Brakes0.6%
  4. Visibility (wipers, screen, mirrors)0.6%
  5. Emissions & leaks0.3%
  6. Suspension0.2%

Most common advisories

Not failures yet, but things the tester warned about.

  1. Tread depth below requirements of 1.6mm10.8%
  2. Brake pads: less than 1.5 mm thick4.9%
  3. Tyres - condition: has a cut in excess of the requirements deep enough to reach the ply or cords3.1%
  4. Tread depth: tread pattern not visible over the whole tread area when minimum depth required is 1.0mm2.6%
  5. Non-component advisories: Nail in tyre1.1%

What this means if you are buying one

This model year does better than most cars its age, so it is a reasonable used buy on MOT record alone. Before buying, check the area that fails most: tyres - condition: has a bulge, caused by separation or partial failure of its structure. Then look up the car's own MOT history on GOV.UK with its number plate, and look for repeat advisories.

← 2020 S-ClassAll S-Class years

Questions

What is the MOT pass rate for a 2021 Mercedes-Benz S-Class?

In 2024, 92.4% of 2021 Mercedes-Benz S-Class cars passed their MOT first time, across 655 tests. The average for all 3-year-old cars was 87.6%.

What are the most common MOT failures on a 2021 Mercedes-Benz S-Class?

The most common failure reasons were tyres - condition: has a bulge, caused by separation or partial failure of its structure; tyres - condition: has a cut in excess of the requirements deep enough to reach the ply or cords; tyres - condition: has ply or cords exposed. The biggest problem area was tyres.

Is the 2021 Mercedes-Benz S-Class reliable at MOT time?

Its MOT Rank score is 105, which is above average for a car of its age (100 means exactly average).