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Mercedes-Benz M-Class seat belts and airbags problems

DVSA MOT tests 2022–2025 · 14,152 MOT tests · Updated

At 10 years, 0.7 in 100 MOT tests of the Mercedes-Benz M-Class failed on seat belts and airbags, against 0.7 for all class 4 vehicles the same age (all test years; 14,152 MOT tests) [1].

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  • Against all class 4 vehicles the same age: about average for all class 4 vehicles the same age (all test years), 105 MOT tests with a fail
  • By age: seen at 18 ages from 7 to 24 years, 139,242 MOT tests
  • Most common fail: Airbag (SRS) warning light on, 0.6 per 100 MOT tests

Figures are for the model as a whole, not for one car.

What the MOT tests show

What we know

0.7 fails per 100 MOT tests at 10 years, against 0.7 for all class 4 vehicles tested at 10 (all test years). That is about average.

Why it matters

A seat belts and airbags fail stops the car passing until it is fixed; the most common one is rated major by DVSA.

What to check

Pull every seat belt out fully and let it retract, check each buckle latches and releases, and make sure the airbag light goes out after start-up.

Mercedes-Benz M-Class seat belts and airbags fails by age

Mercedes-Benz M-Class seat belts and airbags fails per 100 MOT tests by ageSolid line: the Mercedes-Benz M-Class. Dashed line: all cars the same age. The table below lists every value.01237 years: 0.3 per 100 (all cars 0.4), 3,282 MOT tests78 years: 0.4 per 100 (all cars 0.5), 7,249 MOT tests9 years: 0.5 per 100 (all cars 0.6), 11,539 MOT tests910 years: 0.7 per 100 (all cars 0.7), 14,152 MOT tests11 years: 0.6 per 100 (all cars 0.9), 13,780 MOT tests1112 years: 0.8 per 100 (all cars 1.0), 12,787 MOT tests13 years: 1.3 per 100 (all cars 1.2), 10,695 MOT tests1314 years: 1.6 per 100 (all cars 1.5), 10,487 MOT tests15 years: 1.6 per 100 (all cars 1.7), 10,203 MOT tests1516 years: 1.9 per 100 (all cars 2.1), 9,416 MOT tests17 years: 2.1 per 100 (all cars 2.5), 8,031 MOT tests1718 years: 2.4 per 100 (all cars 2.7), 6,935 MOT tests19 years: 2.0 per 100 (all cars 2.9), 5,786 MOT tests1920 years: 2.7 per 100 (all cars 3.1), 4,860 MOT tests21 years: 2.8 per 100 (all cars 3.1), 3,963 MOT tests2122 years: 2.1 per 100 (all cars 3.1), 2,955 MOT tests23 years: 2.8 per 100 (all cars 3.2), 2,031 MOT tests2324 years: 2.2 per 100 (all cars 3.2), 1,091 MOT tests
Fails per 100 MOT tests by age, all first-use years pooled. Mercedes-Benz M-Class All class 4 vehicles the same age Shaded: over 18 years, survivors only.
AgeMOT testsFails per 100All class 4 vehicles the same age
73,2820.30.4
87,2490.40.5
911,5390.50.6
1014,1520.70.7
1113,7800.60.9
1212,7870.81.0
1310,6951.31.2
1410,4871.61.5
1510,2031.61.7
169,4161.92.1
178,0312.12.5
186,9352.42.7
19*5,7862.02.9
20*4,8602.73.1
21*3,9632.83.1
22*2,9552.13.1
23*2,0312.83.2
24*1,0912.23.2

All first-use years of the Mercedes-Benz M-Class pooled at each age, against all class 4 vehicles at that age over all 2022–2025 test years. * Only survivors are still tested at this age.

What fails in the seat belts and airbags at 10 years

Fails

  • Airbag (SRS) warning light on: 0.6 fails per 100 MOT tests, all class 4 vehicles 0.4. Diagnose and fix airbag (SRS) warning: estimated £39–£317 (0.5–1.5 h at £78/h (ONS local-garage repair quotes, 1,058 quotes from 65 garages, Sep 2025 to Aug 2026) + parts £0–£200) Airbag (SRS) warning lamp indicates a fault MOT fail

Diagnose and fix airbag (SRS) warning cost

Repair figures are estimates, not quotes: how we estimate repair costs.

Buying a Mercedes-Benz M-Class? Check that exact car before the viewing.

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  • Model risks for this year and fuel
  • What similar cars did at their next MOT
  • Repairs ahead
  • Viewing checklist

See a sample report

By engine and fuel

  • 3.0 diesel: 0.7 per 100 at 10 years, about average for diesel class 4 vehicles the same age (all test years; 6,094 MOT tests)

How to check on a test drive

Pull every seat belt out fully and let it retract, check each buckle latches and releases, and make sure the airbag light goes out after start-up.

Check one Mercedes-Benz M-Class, not the average

The figures here describe Mercedes-Benz M-Class cars as a group. These free tools answer for one car. Each line says what the tool reads.

Other Mercedes-Benz M-Class problems

Seat belts and airbags on rival models

Questions people ask

Does the Mercedes-Benz M-Class have more seat belts and airbags problems than other cars?

0.7 in 100 MOT tests at 10 years, against 0.7 for all class 4 vehicles the same age: about average by our test (all test years; 14,152 MOT tests).

How common are Mercedes-Benz M-Class seat belts and airbags problems?

0.7 in 100 MOT tests at 10 years failed on seat belts and airbags, against 0.7 for all class 4 vehicles the same age (all test years; 14,152 MOT tests).

What is the most common Mercedes-Benz M-Class seat belts and airbags fail?

0.6 in 100 MOT tests at 10 years: Airbag (SRS) warning light on (86 MOT tests with it).

Sources

  1. Driver and Vehicle Standards Agency, Anonymised MOT tests and results, 2022 to 2025. DVSA MOT data, Open Government Licence v3.0, 139,242 MOT tests. Accessed 7 Oct 2026.
  2. Office for National Statistics, Consumer price inflation, local price quotes (car repair items). ONS price quotes, series 610236. Accessed 7 Oct 2026.

Parts: against all class 4 vehicles at the same age, all 2022–2025 test years pooled, not adjusted for mileage. Breakdowns and non-MOT faults are not in this data. How we compare