Common problems by part
Mercedes-Benz A-Class seat belts and airbags problems
DVSA MOT tests 2022–2025 · 173,010 MOT tests · Updated
At 6 years, 1.3 in 100 MOT tests of the Mercedes-Benz A-Class failed on seat belts and airbags, against 0.4 for all class 4 vehicles the same age (all test years; 173,010 MOT tests) [1].
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- Against all class 4 vehicles the same age: fails 3.3–3.6× as often as all class 4 vehicles the same age (all test years), 2,162 MOT tests with a fail
- By age: seen at 21 ages from 3 to 23 years, 1,360,594 MOT tests
- Most common fail: Airbag (SRS) warning light on, 1.1 per 100 MOT tests
Figures are for the model as a whole, not for one car.
What the MOT tests show
What we know
1.3 fails per 100 MOT tests at 6 years, against 0.4 for all class 4 vehicles tested at 6 (all test years). The Mercedes-Benz A-Class fails more often here.
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 A-Class seat belts and airbags fails by age
| Age | MOT tests | Fails per 100 | All class 4 vehicles the same age |
|---|---|---|---|
| 3 | 141,475 | 1.1 | 0.3 |
| 4 | 161,782 | 1.4 | 0.3 |
| 5 | 171,041 | 1.3 | 0.3 |
| 6 | 173,010 | 1.3 | 0.4 |
| 7 | 148,489 | 1.2 | 0.4 |
| 8 | 130,797 | 1.6 | 0.5 |
| 9 | 105,453 | 2.5 | 0.6 |
| 10 | 72,287 | 3.2 | 0.7 |
| 11 | 50,730 | 3.0 | 0.9 |
| 12 | 33,511 | 2.2 | 1.0 |
| 13 | 25,200 | 1.1 | 1.2 |
| 14 | 27,065 | 1.5 | 1.5 |
| 15 | 27,947 | 1.8 | 1.7 |
| 16 | 26,573 | 2.2 | 2.1 |
| 17 | 22,127 | 2.7 | 2.5 |
| 18 | 15,715 | 2.8 | 2.7 |
| 19* | 10,656 | 2.9 | 2.9 |
| 20* | 7,083 | 2.6 | 3.1 |
| 21* | 4,505 | 2.4 | 3.1 |
| 22* | 3,184 | 2.6 | 3.1 |
| 23* | 1,964 | 2.1 | 3.2 |
All first-use years of the Mercedes-Benz A-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 6 years
Fails
- Airbag (SRS) warning light on: 1.1 fails per 100 MOT tests, all class 4 vehicles 0.2. 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 A-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
By engine and fuel
- 1.5 diesel: 1.4 per 100 at 6 years, fails 3.0–3.4× as often as diesel class 4 vehicles the same age (all test years; 68,529 MOT tests)
- 1.3 petrol: 2.4 per 100 at 6 years, fails 7.0–8.0× as often as petrol class 4 vehicles the same age (all test years; 34,451 MOT tests)
- 1.6 petrol: 0.3 per 100 at 6 years, about average for petrol class 4 vehicles the same age (all test years; 27,694 MOT tests)
- 2.1 diesel: 0.3 per 100 at 6 years, about average for diesel class 4 vehicles the same age (all test years; 26,321 MOT tests)
- 2.0 petrol: 1.1 per 100 at 6 years, about average for petrol class 4 vehicles the same age (all test years; 12,328 MOT tests)
- 2.0 diesel: 2.1 per 100 at 6 years, about average for diesel class 4 vehicles the same age (all test years; 3,590 MOT tests)
- 1.5 petrol: 2.7 per 100 at 16 years, fails 1.4–1.7× as often as petrol class 4 vehicles the same age (all test years; 13,917 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 A-Class, not the average
The figures here describe Mercedes-Benz A-Class cars as a group. These free tools answer for one car. Each line says what the tool reads.
- Check a Mercedes-Benz A-Class'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 A-Class problems
- Mercedes-Benz A-Class suspension problems
- Mercedes-Benz A-Class brakes problems
- Mercedes-Benz A-Class lights and electrics problems
- Mercedes-Benz A-Class steering problems
- Mercedes-Benz A-Class exhaust, emissions and leaks problems
- Mercedes-Benz A-Class windscreen, wipers and mirrors problems
- Mercedes-Benz A-Class tyres problems
- Mercedes-Benz A-Class road wheels problems
Seat belts and airbags on rival models
- Citroen C4 seat belts and airbags problems: 0.3 per 100 MOT tests at 6 years, against 1.3 for the Mercedes-Benz A-Class (26,517 MOT tests)
Questions people ask
Does the Mercedes-Benz A-Class have more seat belts and airbags problems than other cars?
3.3 to 3.6 times the seat belts and airbags fail rate of all class 4 vehicles the same age at 6 years (all test years), from 173,010 MOT tests. The interval is clear of 1.2 in the same direction at 10 of the 21 ages seen (ages up to 18 with at least 100 MOT tests with a fail).
How common are Mercedes-Benz A-Class seat belts and airbags problems?
1.3 in 100 MOT tests at 6 years failed on seat belts and airbags, against 0.4 for all class 4 vehicles the same age (all test years; 173,010 MOT tests).
What is the most common Mercedes-Benz A-Class seat belts and airbags fail?
1.1 in 100 MOT tests at 6 years: Airbag (SRS) warning light on (1,966 MOT tests with it).
Sources
- Driver and Vehicle Standards Agency, Anonymised MOT tests and results, 2022 to 2025. DVSA MOT data, Open Government Licence v3.0, 1,360,594 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