Mercedes-Benz B MOT Pass Rate
Overall pass rate across all manufacture years, based on 179,546 real MOT test results. Failure rate: 22.3%.
Data from official DVSA MOT testing records
Mercedes-Benz B MOT Reliability Overview
The Mercedes-Benz B is a well-known vehicle in the UK, with 179,546 MOT test results recorded in our database spanning 18 manufacture years. It has an overall MOT pass rate of 77.7% and a failure rate of 22.3%, which is well above the UK average of approximately 37%.
Based on this data, the Mercedes-Benz B earns a "Excellent" reliability rating. The average Mercedes-Benz B presents for MOT with approximately 51,419 miles on the clock. Manufacture year matters: 2022 models achieve the highest pass rate at 100.0%, while 2005 models have the lowest at 57.5%. This 42.5 percentage point difference suggests notable variation in build quality or component durability across production years.
The most common MOT failure for the Mercedes-Benz B is Brakes, affecting 18.1% of all tests. Brake-related failures include worn brake pads, corroded brake discs, leaking brake lines, and faulty brake servos. These are safety-critical components — any brake deficiency will result in an MOT fail. The second most common issue is Tyres at 16.5%. Lamps, reflectors and electrical equipment rounds out the top three at 9.6%. Together, these top 3 failure categories account for a significant portion of all MOT failures for this model.
Top failures across all manufacture years combined. Individual year pages may show different top failures.
What Fails Most
Best Year to Buy
All manufacture years perform similarly at ~93.0%.
Based on 2024 MOT test results only — the most recent data available. "Built" = year of manufacture. Cars need their first MOT at 3 years old, so the newest cars shown are from ~3 years ago.
Bar chart showing pass rate by manufacture year from 2006 to 2021
| Built | Pass Rate | Tests | Verdict |
|---|---|---|---|
| 2021 | 93.0% | 1,921 | 🏆 Best |
| 2020 | 92.5% | 3,531 | ✅ Great |
| 2017 | 90.2% | 6,223 | 👍 Good |
| 2019 | 90.1% | 5,014 | 👍 Good |
| 2016 | 86.1% | 4,210 | ⚠️ Fair |
| 2015 | 86.0% | 4,411 | ⚠️ Fair |
| 2014 | 81.9% | 5,187 | ❌ Avoid |
| 2013 | 80.8% | 4,191 | ❌ Avoid |
| 2012 | 76.7% | 4,032 | ❌ Avoid |
| 2010 | 66.4% | 3,385 | ❌ Avoid |
| 2011 | 66.0% | 2,709 | ❌ Avoid |
| 2009 | 64.6% | 3,215 | ❌ Avoid |
| 2008 | 60.3% | 2,606 | ❌ Avoid |
| 2007 | 58.8% | 2,269 | ❌ Avoid |
| 2006 | 58.6% | 2,012 | ❌ Avoid |
📈 How Each Vintage Ages
Tracking how each manufacture year's MOT pass rate changes as the car ages. Showing 13 vintages — click year chips to highlight.
Multi-line chart showing how different Mercedes-Benz B vintages degrade over time, from age 2 to 20 years.
Only vintages with 100+ tests in at least 3 different test years are shown. Fleet average is the UK-wide pass rate for all cars at each age.
📉 How Age Affects Reliability
MOT failure rate by vehicle age for the Mercedes-Benz B. The dashed red line marks when the manufacturer warranty typically expires (3 years).
Line chart showing MOT failure rate by vehicle age from 3 to 15 years, with warranty expiry marked at 3 years.
💡 What does the warranty cliff mean?
The Mercedes-Benz B shows a moderate increase in MOT failures after warranty. The 39% increase is typical — plan for gradual maintenance cost increases. Peak failure occurs at age 15 (44.1% fail rate).
Note: pass rates may improve for very old vehicles due to survivorship bias — only well-maintained cars remain on the road.
* High Fail Rate badge indicates an MOT pass rate below 65% (failure rate above 35%).
What Fails on This Car?
Click a category to see specific failure items.
View as table
| Rank | Failure Category | Rate (%) | Count |
|---|---|---|---|
| 1 | Brakes | 18.1% | 32,447 |
| 2 | Tyres | 16.5% | 29,599 |
| 3 | Lamps, Reflectors And Electrical Equipment | 14.7% | 26,424 |
| 4 | Suspension | 8.7% | 15,674 |
| 5 | Non-component Advisories | 3.3% | 5,927 |
| 6 | Visibility | 3.0% | 5,299 |
| 7 | Body, Chassis, Structure | 2.6% | 4,752 |
| 8 | Noise, Emissions And Leaks | 1.7% | 2,971 |
| 9 | Seat Belts And Supplementary Restraint Systems | 1.3% | 2,187 |
| 10 | Road Wheels | 1.2% | 2,237 |
| 11 | Driver's View Of The Road | 1.2% | 2,221 |
| 12 | Identification Of The Vehicle | 0.6% | 1,086 |
| 13 | Steering | 0.5% | 876 |
Failures per 10,000 Miles
avg. 51,419 miFor every 10,000 miles driven, this shows what percentage of MOT tests fail for each category. This accounts for how far cars are actually driven, not just raw pass/fail counts.
View as table
| Category | Rate / 10K mi | Raw % | Count |
|---|---|---|---|
| Brakes | 3.51 | 18.1% | 32,447 |
| Tyres | 3.21 | 16.5% | 29,599 |
| Lamps & Electrical | 2.86 | 14.7% | 26,424 |
| Suspension | 1.70 | 8.7% | 15,674 |
| Visibility | 0.81 | 4.2% | 7,520 |
| Non-component advisories | 0.64 | 3.3% | 5,927 |
| Body & Structure | 0.51 | 2.6% | 4,752 |
| Noise, emissions and leaks | 0.32 | 1.7% | 2,971 |
| Seat Belts | 0.24 | 1.3% | 2,187 |
| Wheels | 0.24 | 1.2% | 2,237 |
| Identification of the vehicle | 0.12 | 0.6% | 1,086 |
| Steering | 0.09 | 0.5% | 876 |
🚗 Similar Cars to Consider
Mileage at MOT
The average Mercedes-Benz B has 51,419 miles when tested for MOT.
📊 Mileage-Adjusted Failure Rate
How often this car fails MOT relative to how much it's driven — a fairer comparison than raw pass rate.
The Mercedes-Benz B has a mileage-adjusted failure rate of 4.34% per 10,000 miles driven. The average across all makes is 5.38%, so this model is better than average.
About Mercedes-Benz B MOT Data
The Mercedes-Benz B is a well-known vehicle in the UK, with 179,546 MOT test results recorded in our database spanning 18 manufacture years. It has an overall MOT pass rate of 77.7% and a failure rate of 22.3%, which is well above the UK average of approximately 37%.
For Mercedes-Benz B owners, these results suggest a reliable vehicle that generally passes its MOT without major issues. Focus your pre-MOT checks on brakes and tyres for the best chance of a first-time pass. Use our detailed year-by-year breakdown and failure analysis below to understand how your specific B is likely to perform.
Brakes — 18.1% of failures
Brakes issues account for 18.1% of MOT failures on the Mercedes-Benz B. Brake-related failures include worn brake pads, corroded brake discs, leaking brake lines, and faulty brake servos. These are safety-critical components — any brake deficiency will result in an MOT fail. Typical repair costs: £150–400. Pre-MOT check: Listen for squealing or grinding noises. Check brake pedal feel — if it feels spongy or goes to the floor, have the system inspected immediately. Look at brake pad thickness through the wheel spokes (minimum 3mm).
Tyres — 16.5% of failures
Tyres issues account for 16.5% of MOT failures on the Mercedes-Benz B. Tyre failures include tread depth below the legal minimum of 1.6mm, cuts, bulges, exposed cords, and incorrect tyre pressure. Tyres are one of the most common and easiest-to-prevent MOT failures. Typical repair costs: £50–200 per tyre. Pre-MOT check: Check tread depth with a 20p coin — if the outer band is visible, the tyre is too worn. Look for bulges, cuts, or embedded objects. Ensure all tyres match the recommended size and load rating.
Lamps, reflectors and electrical equipment — 9.6% of failures
Lamps, reflectors and electrical equipment issues account for 9.6% of MOT failures on the Mercedes-Benz B. Lighting failures cover all external lights: headlights, tail lights, brake lights, indicators, fog lights, and reflectors. A single blown bulb will cause an MOT fail. This is one of the most preventable failure categories. Typical repair costs: £5–50. Pre-MOT check: Walk around the car and check every light — headlights (dipped and main beam), side lights, tail lights, brake lights, indicators, hazard lights, reverse light, rear fog light, and number plate lights. Replace any blown bulbs before the test.
Frequently Asked Questions
What is the MOT pass rate for the Mercedes-Benz B?
Based on 179,546 MOT tests in our database, the Mercedes-Benz B has an overall pass rate of 77.7% (22.3% fail rate).
What are the most common MOT failures on a Mercedes-Benz B?
The top 3 reasons a Mercedes-Benz B fails its MOT are: 1. Brakes (18.1%), 2. Tyres (16.5%), 3. Lamps, reflectors and electrical equipment (9.6%). Check these areas before booking your MOT.
Is the Mercedes-Benz B reliable?
With a 22.3% MOT failure rate, the B is more reliable than average compared to the UK average of ~40%.
What should I check before an MOT on my Mercedes-Benz B?
Based on failure data, focus on: Brakes (18.1%); Tyres (16.5%); Lamps, reflectors and electrical equipment (9.6%). These are the areas most likely to cause a fail. Also check all lights, tyres (minimum 1.6mm tread), and windscreen condition — these are quick wins that apply to all cars.
Based on DVSA anonymised MOT test data (2005–2024). Crown copyright, Open Government Licence v3.0.