2021 Mercedes-Benz A-Class MOT pass rate, common failures & what to check
In 2025, 89.7% of Mercedes-Benz A-Class cars first used in 2021 passed their MOT first time, against 87.2% for all cars first used in 2021. Across 63,095 A-Class first tests from 2023 to 2025, the most common failure areas were tyres, visibility (wipers, washers and windscreen) and lamps and electrical equipment.
This page analyses first MOT tests for Mercedes-Benz A-Class cars first used in 2021 (all trims grouped): 2021 to 2025 for the pass-rate trend, and 2023 to 2025 for the failure and advisory analysis — plus what is worth checking before you buy one.
Data: DVSA anonymised MOT tests to December 2025 · Calculated by SortedCars · Updated October 2026
How the 2021 Mercedes-Benz A-Class MOT pass rate has changed
Share of first tests passed in each year, A-Class cars first used in 2021 against all cars first used in 2021 (any make or fuel; not adjusted for mileage, fuel or use). In 2025 the A-Class figure was 2.5 points higher.
View this chart as a table
| Test year | 2021 A-Class | All cars first used 2021 | A-Class first tests |
|---|---|---|---|
| 2021 | fewer than 500 tests | 82.9% | 11 |
| 2022 | fewer than 500 tests | 89.9% | 26 |
| 2023 | 93.6% | 90.8% | 1,407 |
| 2024 | 89.8% | 87.6% | 31,418 |
| 2025 | 89.7% | 87.2% | 30,270 |
Common 2021 Mercedes-Benz A-Class MOT failures
Share of the 6,412 failed first tests (2023–2025) with at least one failure in each area. A test can fail in more than one area, so the shares add up to more than 100%.
Most common failure items
| DVSA failure item | Share of failed first tests | Tests |
|---|---|---|
| Tyre condition: has a cut in excess of the requirements deep enough to reach the ply or cords | 22.6% | 1,451 |
| Tread depth: below requirements of 1.6mm | 13.1% | 843 |
| Tyre condition: has ply or cords exposed | 10.9% | 697 |
| Wipers: does not clear the windscreen effectively | 9.5% | 612 |
| Brake pads: less than 1.5 mm thick | 6.2% | 400 |
Item names are DVSA’s own wording. 2023–2025 combined.
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What to check on a 2021 Mercedes-Benz A-Class before buying
The three areas where failed first tests most often had a fault, 2023–2025.
- Tyres. Worth checking the tread depth across the whole width of each tyre, and the sidewalls for cuts, cracks and bulges.
- Wipers and windscreen. Worth checking that the wipers clear the screen cleanly, that the washers work, and that there are no chips or cracks in the driver’s view.
- Lamps and electrics. Ask someone to watch while you work the brake lights, indicators, sidelights, dipped and main beam, and the number-plate lamps.
Common 2021 Mercedes-Benz A-Class MOT advisories
Advisories are points the tester noted that did not fail the car. Most common on 2021 A-Class cars, as a share of all 63,095 first tests, 2023–2025.
| DVSA advisory item | Share of first tests | Tests |
|---|---|---|
| Tread depth: worn close to legal limit/worn on edge | 13.1% | 8,287 |
| Tyre condition: slightly damaged/cracking or perishing | 5.3% | 3,366 |
| Brake pads: wearing thin | 4.8% | 3,028 |
| Tread depth: worn close to legal limit/worn on edge | 2.2% | 1,414 |
| Tyre condition: has a cut but not deep enough to reach the ply or cords | 2.1% | 1,351 |
Questions about the 2021 Mercedes-Benz A-Class MOT
What is the MOT pass rate of a 2021 Mercedes-Benz A-Class?
In 2025, 89.7% of A-Class cars first used in 2021 passed their MOT first time, against 87.2% for all cars first used in 2021. A car fixed during the test counts as a fail.
What does a 2021 A-Class most often fail its MOT on?
Tyres (in 54.4% of failed first tests, 2023–2025), visibility (wipers, washers and windscreen) (16.1%) and lamps and electrical equipment (13.5%). The single most common item was “Tyre condition: has a cut in excess of the requirements deep enough to reach the ply or cords” (22.6%).
How often does a 2021 Mercedes-Benz A-Class fail its MOT?
In 2025, 10.3% of first tests on A-Class cars first used in 2021 did not pass first time: 8.6% failed, and a further 1.7% had a fault fixed during the test (counted as a fail here). Across 2023–2025, 6,412 of 63,095 first tests did not pass first time.
What are the most common 2021 Mercedes-Benz A-Class MOT advisories?
“Tread depth: worn close to legal limit/worn on edge” (on 13.1% of first tests, 2023–2025), “Tyre condition: slightly damaged/cracking or perishing” (5.3%), “Brake pads: wearing thin” (4.8%), “Tread depth: worn close to legal limit/worn on edge” (2.2%) and “Tyre condition: has a cut but not deep enough to reach the ply or cords” (2.1%).
Is a 2021 Mercedes-Benz A-Class reliable?
An MOT pass rate shows what failed at the test, not how reliable a car is. For this group of cars the first-time pass rate went from 93.6% in 2023 to 89.7% in 2025. For one particular car, its own MOT history matters more than the average.
Other cars first used in 2021
The most-tested cars from the same year. Each page uses the same method.
2021 Vauxhall Corsa MOT statistics · 2021 Ford Transit Custom MOT statistics · 2021 MINI Hatch MOT statistics · 2021 Tesla Model 3 MOT statistics · 2021 Nissan Qashqai MOT statistics
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