2009 Mercedes-Benz B-Class MOT pass rate, common failures & what to check
In 2025, 58.2% of Mercedes-Benz B-Class cars first used in 2009 passed their MOT first time, against 58.3% for all cars first used in 2009. Across 13,180 B-Class first tests from 2023 to 2025, the most common failure areas were lamps and electrical equipment, suspension and brakes.
This page analyses first MOT tests for Mercedes-Benz B-Class cars first used in 2009 (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 2009 Mercedes-Benz B-Class MOT pass rate has changed
Share of first tests passed in each year, B-Class cars first used in 2009 against all cars first used in 2009 (any make or fuel; not adjusted for mileage, fuel or use). In 2025 the B-Class figure was in line with the all-cars figure.
View this chart as a table
| Test year | 2009 B-Class | All cars first used 2009 | B-Class first tests |
|---|---|---|---|
| 2021 | 61.9% | 60.5% | 5,118 |
| 2022 | 61.7% | 60.1% | 4,991 |
| 2023 | 58.8% | 59.0% | 4,780 |
| 2024 | 56.5% | 58.4% | 4,380 |
| 2025 | 58.2% | 58.3% | 4,020 |
Common 2009 Mercedes-Benz B-Class MOT failures
Share of the 5,557 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 |
|---|---|---|
| Drive shaft joints: constant velocity boot split or insecure, no longer prevents the ingress of dirt | 14.3% | 797 |
| Coil spring: fractured or broken | 14.1% | 781 |
| Ball joint: excessively worn | 11.7% | 649 |
| Rigid brake pipes: excessively corroded | 9.7% | 537 |
| Parking brake efficiency (sp): efficiency below requirements | 7.5% | 414 |
Item names are DVSA’s own wording. 2023–2025 combined.
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Typical repair costs for common MOT failures
Typical UK garage prices for the job, not for a B-Class in particular, and not a quote.
| Failure item | Typical job | Typical UK price | Usual range |
|---|---|---|---|
| Coil spring: fractured or broken | Coil spring replacement | £248 | £175–£400 |
| Ball joint: excessively worn | Ball joint replacement | £90 | £60–£150 |
From published UK repair-cost guides, checked September 2026. Only jobs with a published typical price are shown.
What to check on a 2009 Mercedes-Benz B-Class before buying
The three areas where failed first tests most often had a fault, 2023–2025.
- Lamps and electrics. Ask someone to watch while you work the brake lights, indicators, sidelights, dipped and main beam, and the number-plate lamps.
- Suspension. Worth looking behind the front wheels with a torch at the coil springs, and listening for knocks over bumps on the test drive.
- Brakes. Worth looking at the discs and pads through the wheel spokes for scoring and a worn lip, and noticing on the test drive whether the car pulls to one side or the pedal feels long.
Common 2009 Mercedes-Benz B-Class MOT advisories
Advisories are points the tester noted that did not fail the car. Most common on 2009 B-Class cars, as a share of all 13,180 first tests, 2023–2025.
| DVSA advisory item | Share of first tests | Tests |
|---|---|---|
| Rigid brake pipes: corroded, covered in grease or other material | 22.9% | 3,019 |
| Tread depth: worn close to legal limit/worn on edge | 15.4% | 2,028 |
| Brake discs: worn, pitted or scored, but not seriously weakened | 13.7% | 1,810 |
| Tyre condition: slightly damaged/cracking or perishing | 10.8% | 1,420 |
| Brake pads: wearing thin | 7.9% | 1,037 |
Questions about the 2009 Mercedes-Benz B-Class MOT
What is the MOT pass rate of a 2009 Mercedes-Benz B-Class?
In 2025, 58.2% of B-Class cars first used in 2009 passed their MOT first time, against 58.3% for all cars first used in 2009. A car fixed during the test counts as a fail.
What does a 2009 B-Class most often fail its MOT on?
Lamps and electrical equipment (in 41.4% of failed first tests, 2023–2025), suspension (39.1%) and brakes (32.1%). The single most common item was “Drive shaft joints: constant velocity boot split or insecure, no longer prevents the ingress of dirt” (14.3%).
How often does a 2009 Mercedes-Benz B-Class fail its MOT?
In 2025, 41.8% of first tests on B-Class cars first used in 2009 did not pass first time: 34.8% failed, and a further 7.1% had a fault fixed during the test (counted as a fail here). Across 2023–2025, 5,557 of 13,180 first tests did not pass first time.
What are the most common 2009 Mercedes-Benz B-Class MOT advisories?
“Rigid brake pipes: corroded, covered in grease or other material” (on 22.9% of first tests, 2023–2025), “Tread depth: worn close to legal limit/worn on edge” (15.4%), “Brake discs: worn, pitted or scored, but not seriously weakened” (13.7%), “Tyre condition: slightly damaged/cracking or perishing” (10.8%) and “Brake pads: wearing thin” (7.9%).
Is a 2009 Mercedes-Benz B-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 61.9% in 2021 to 58.2% in 2025. For one particular car, its own MOT history matters more than the average.
Other cars first used in 2009
The most-tested cars from the same year. Each page uses the same method.
2009 Ford Fiesta MOT statistics · 2009 Ford Focus MOT statistics · 2009 Vauxhall Corsa MOT statistics · 2009 Volkswagen Golf MOT statistics · 2009 Vauxhall Astra MOT statistics
Checking a specific 2009 B-Class?
The numbers above cover every B-Class first used in 2009 and tested in Great Britain. Our free check shows the actual MOT history, mileage record and tax status of the one you are looking at.
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