Common problems by part
Mercedes-Benz GLB seat belts and airbags problems
DVSA MOT tests 2022–2025 · 12,047 MOT tests · Updated
At 3 years, 0.5 in 100 MOT tests of the Mercedes-Benz GLB failed on seat belts and airbags, against 0.3 for all class 4 vehicles the same age (all test years; 12,047 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), 57 MOT tests with a fail
- When it starts: clear of 1.2 times from 5 years and at every older age seen
- Most common fail: Airbag (SRS) warning light on, 0.2 per 100 MOT tests
Figures are for the model as a whole, not for one car.
What the MOT tests show
What we know
0.5 fails per 100 MOT tests at 3 years, against 0.3 for all class 4 vehicles tested at 3 (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 GLB seat belts and airbags fails by age
| Age | MOT tests | Fails per 100 | All class 4 vehicles the same age |
|---|---|---|---|
| 3 | 12,047 | 0.5 | 0.3 |
| 4 | 6,756 | 0.4 | 0.3 |
| 5 | 2,612 | 1.1 | 0.3 |
All first-use years of the Mercedes-Benz GLB pooled at each age, against all class 4 vehicles at that age over all 2022–2025 test years.
What fails in the seat belts and airbags at 3 years
Fails
- Airbag (SRS) warning light on: 0.2 fails per 100 MOT tests, all class 4 vehicles 0.1. 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 GLB? Check that exact car before the viewing.
Buying Report £14.99 incl. VAT · one car · no subscription · Not a mechanical inspection.
- Model risks for this year and fuel
- What similar cars did at their next MOT
- Repairs ahead
- Viewing checklist
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 GLB, not the average
The figures here describe Mercedes-Benz GLB cars as a group. These free tools answer for one car. Each line says what the tool reads.
- Check a Mercedes-Benz GLB's MOT history Every MOT test, fail item, advisory and mileage reading DVSA holds for that registration.
- MOT advisory checker Paste an advisory or defect to read DVSA's wording, its grade and what tends to happen at the next MOT.
Other Mercedes-Benz GLB problems
Seat belts and airbags on rival models
- Volvo XC40 seat belts and airbags problems: 0.2 per 100 MOT tests at 3 years, against 0.5 for the Mercedes-Benz GLB (82,664 MOT tests)
- Vauxhall Grandland seat belts and airbags problems: 0.6 per 100 MOT tests at 3 years, against 0.5 for the Mercedes-Benz GLB (61,758 MOT tests)
- Peugeot 3008 seat belts and airbags problems: 0.4 per 100 MOT tests at 3 years, against 0.5 for the Mercedes-Benz GLB (53,468 MOT tests)
Questions people ask
Does the Mercedes-Benz GLB have more seat belts and airbags problems than other cars?
0.5 in 100 MOT tests at 3 years, against 0.3 for all class 4 vehicles the same age: about average by our test (all test years; 12,047 MOT tests).
How common are Mercedes-Benz GLB seat belts and airbags problems?
0.5 in 100 MOT tests at 3 years failed on seat belts and airbags, against 0.3 for all class 4 vehicles the same age (all test years; 12,047 MOT tests).
What is the most common Mercedes-Benz GLB seat belts and airbags fail?
0.2 in 100 MOT tests at 3 years: Airbag (SRS) warning light on (25 MOT tests with it).
At what age do Mercedes-Benz GLB seat belts and airbags fails start?
5 years: from then on the rate stays clear of 1.2 times all class 4 vehicles the same age at every age seen, 2,612 MOT tests.
Sources
- Driver and Vehicle Standards Agency, Anonymised MOT tests and results, 2022 to 2025. DVSA MOT data, Open Government Licence v3.0, 21,415 MOT tests. Accessed 7 Oct 2026.
- 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