Mercedes Benz A Class MOT Failures
An analysis of 743,664 real DVSA MOT tests on the Mercedes Benz A Class — what fails, how often, and how that compares to every other car on UK roads.
Where the Mercedes Benz A Class fails its MOT
The single biggest MOT failure point on the Mercedes Benz A Class is emissions failure — this model is 318 times more likely to fail on this item than the average car on UK roads. That makes it an extreme outlier for anyone buying or owning this model. Across 743,664 MOT tests, 4.82% of all Mercedes Benz A Class tests recorded this as a failure.
Exhaust and emissions failures often point to catalytic converter degradation, lambda sensor faults, or — in diesel models — DPF problems. These can be expensive to fix and will cause an immediate MOT failure.
Other notable weak points include fuel pipe or hose damaged (114x the fleet average), excessive radial movement between the top of th... (69x the fleet average), brake hoses perished or damaged (78x the fleet average), and excessive wear or play in a universal joint or ... (163x the fleet average). These ratios compare the Mercedes Benz A Class's failure rate on each item against the national average for all cars tested — a ratio of 10x means this model fails ten times more often than a typical car.
The failures span 6 categories: Exhaust & Emissions, Bodywork, Steering, Brakes, Seatbelts & Airbags and others. If you're inspecting a Mercedes Benz A Class before purchase, these are the areas to focus on — and if any have been flagged as advisories on a previous MOT, they're likely to become failures in the near future.
How failures change with mileage
The Mercedes Benz A Class's weak points shift as the car covers more miles. Understanding these patterns helps you know what to expect — and what to budget for — at each stage of ownership.
Under 60,000 miles
At this mileage, most failures are either design-related or caused by age rather than wear. Components like bushes and drop links may not have been replaced yet, and original-fit parts can deteriorate even on low-mileage cars that spend a lot of time sitting.
For the Mercedes Benz A Class specifically, the DVSA data shows the most common failures at this mileage are emissions failure (318x the average) and excessive wear or play in a universal joint or ... (163x). brake lining or pad missing or incorrectly mounted (117x) and fuel pipe or hose damaged (114x) also appear frequently.
60,000 to 100,000 miles
This is where routine wear items start to show up. Brake components, tyres, and exhaust parts have done serious work by this point. Cars that have been well serviced will show fewer of these failures — this mileage band is where good maintenance really separates the well-kept from the neglected.
For the Mercedes Benz A Class specifically, the DVSA data shows the most common failures at this mileage are airbag fault (40x the average) and emissions failure (31x). fuel pipe or hose damaged (27x) and brake hoses perished or damaged (25x) also appear frequently.
Over 100,000 miles
High-mileage cars accumulate failures across multiple systems. The key question isn't whether things will need doing — they will — but whether the car has been maintained well enough to keep on top of them. Look for a consistent service history and recent MOT passes with minimal advisories.
For the Mercedes Benz A Class specifically, the DVSA data shows the most common failures at this mileage are airbag fault (76x the average) and tyre valve seriously damaged or misaligned (24x). excessive wear or play in a universal joint or ... (24x) and excessive radial movement between the top of th... (20x) also appear frequently.
The shift from emissions failure at lower mileages to airbag fault at higher mileages is typical — early failures tend to be design or factory-related, while high-mileage failures reflect accumulated mechanical wear. A car that's been well maintained will usually dodge the worst of both.
What to check before buying a Mercedes Benz A Class
Based on the MOT failure data and known issues above, here's what to prioritise when inspecting a Mercedes Benz A Class:
Exhaust & Emissions — check for emissions failure. Bodywork — check for fuel pipe or hose damaged. Steering — check for excessive radial movement between the top of th..., excessive wear or play in a universal joint or .... Brakes — check for brake hoses perished or damaged, brake lining or pad missing or incorrectly mounted.
Always check the car's full MOT history for patterns — recurring advisories often become failures within 12 months. And verify the service history to confirm maintenance has been kept up to schedule. Enter any reg into our free car check to see the complete picture.
Looking at a specific Mercedes Benz A Class?
Enter the reg to see its full MOT history, mileage records, write-off status, and finance checks.
Mercedes Benz A Class MOT FAQs
What are the most common MOT failures on a Mercedes Benz A Class?
Based on 743,664 DVSA MOT tests, the most common failure is emissions failure — at 318x the national fleet average. Other frequent failures include fuel pipe or hose damaged and excessive radial movement between the top of th....
Is the Mercedes Benz A Class reliable based on MOT data?
The Mercedes Benz A Class has 19 categories where it fails more often than average. The main concern is emissions failure. Always check a specific car's full history before buying.
What MOT failures should I expect at high mileage?
Above 100,000 miles, the Mercedes Benz A Class most commonly fails on airbag fault and tyre valve seriously damaged or misaligned. Under 60,000 miles, the main issues are emissions failure and excessive wear or play in a universal joint or ....
How do I check a Mercedes Benz A Class's MOT history?
Enter the registration number into our free car check above. You'll see every MOT test result, advisories and failures, mileage readings, write-off status, and finance checks.
MOT failure data sourced from DVSA bulk test records via data.gov.uk. Ratios compare this model's failure rate against the national fleet average. Known issues sourced from manufacturer bulletins, specialist workshops, and verified owner reports.