Mercedes Benz

Mercedes Benz B Class (2009)

5,689 real MOT outcomes analysed • 77.8% first-time pass rate

2009 Mercedes Benz B Class

CarHunch analysed 5,689 real MOT records for the 2009 Mercedes Benz B Class. Real test outcomes — pass rates, defect profiles, mileage data — from verified DVLA records. Updated as new MOTs are recorded.
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AI Analysis Reliability Overview Common Issues Check a Specific Reg Buyer's Checklist Pass Rate by Fuel Mileage Distribution Still on the Road MOT Averages Colour Breakdown Compare Models

The 2009 Mercedes-Benz B-Class falls slightly below the UK average with a 77.8% first-time pass rate, but the real concern is that 45.2% of these vehicles have recorded a dangerous defect at some point—well above the typical threshold and a serious red flag for buyers. Petrol and diesel variants perform nearly identically (78.1% and 77.5% respectively), so fuel type won't meaningfully change your odds here.

At nearly 71,000 miles median mileage for a 15-year-old car, these B-Classes have been driven fairly hard, and the data reflects it: owners face an average of 3.85 failures and 22.4 advisories per test cycle. Before committing to one, get a thorough pre-purchase inspection focusing on suspension, braking system, and electrical components—the high dangerous defect rate suggests structural or safety-critical wear is common in this generation.

The 2009 Mercedes Benz B Class has a decent first-time pass rate (77.8%), but a higher-than-average share of vehicles have had serious defects recorded — the individual vehicle's history matters a lot here.

⚠️ Over 1 in 5 of these vehicles have had a dangerous MOT failure at some point — usually tyres or brakes, and often a one-off issue rather than a persistent problem. The group stats won't tell you which one you're looking at.
First-time pass
77.8%
UK average ~80%
Around average
Dangerous (ever)
45.2%
At least once in MOT history
Check this vehicle
Avg failures / car
3.85
Over 16.4 tests on record
High
Typical mileage
71k
Middle half: 56k–86k
For context
🔧 Average reliability. Passes at roughly the UK rate — not a standout, not a problem vehicle. Individual history makes all the difference.
🔧 Expect consumable spend. An average of 22.4 advisories per vehicle tells you wear items (tyres, brakes) get flagged regularly. Budget for them — they're not surprises.
🔍 The dangerous defect figure is real. Most are one-off tyre failures or brake issues — not structural problems. But it's exactly why checking the individual vehicle's history is essential, not optional.

These stats describe 5,689 vehicles as a group. The specific vehicle you're looking at could be the one good example or the one outlier. Run its registration to find out.

Watch for defects — worth knowing

What tends to go wrong

Across 5,689 vehicles — figures show how many had each issue flagged at least once in their MOT history.

Other issues 60.4%
Under-trays fitted obscuring some underside components · Child seat fitted not allowing full inspection of adult belt · Engine covers fitted obscuring some components in the engine bay
Brake wear 50.5%
Nearside Rear Brake pipe corroded, covered in grease or other material · Rear Brake pad(s) wearing thin · Offside Rear Brake pipe corroded, covered in grease or other material · …
Ask the seller when brakes were last serviced. If they don't know, factor in the cost.
Tyre wear 47.4%
Nearside Front Tyre worn close to the legal limit · Nearside Front Tyre worn close to legal limit/worn on edge · Offside Front Tyre worn close to the legal limit · …
Budget for a full set — on a vehicle this age, tyres are expected consumables. An inspection will confirm how much is left.

Data covers a 3-year window centred on 2009.

See this vehicle's full MOT history & AI hunches

Spot recurring advisories, hidden issues, and how it compares to 5,689 Mercedes Benz B Class cars.

UK

Before you buy a 2009 Mercedes Benz B Class

Based on MOT data from 5,689 vehicles — here's what to check.

  • 📋 Check the full MOT history. 45.2% of these vehicles have had a dangerous defect recorded - recurring advisories often signal problems years before they become failures.
    Search the reg on CarHunch for the full MOT history, reliability stats and a free AI-powered analysis of that exact vehicle.
  • 🔍 Brake pipes, sills and subframes are the key areas on a vehicle this age — structural rust is hard to spot without getting underneath. A mechanic will check all of this before you commit, and give you a concrete basis to negotiate on price. Inspection ClickMechanic
  • 📄 Outstanding finance, insurance write-offs and clocking won't appear in the MOT records — a dedicated history check covers all of this. Our link gets you 20% off automatically. History carVertical Get 20% off via CarHunch

Pass Rate by Fuel Type

Fuel type Vehicles Pass rate Avg failures
Diesel (53%) 2,995 77.5% 3.88
Petrol (47%) 2,694 78.1% 3.83

Colour Breakdown

Based on 77,010 Mercedes Benz B Class vehicles registered in the UK — across all years. From DVLA registration records.

Black 24.5%
18,872
Silver 22.4%
17,281
Grey 19.2%
14,820
Blue 17%
13,065
White 9.9%
7,612
Red 4.9%
3,768
Gold 0.6%
441
Purple 0.5%
393
Brown 0.4%
285
Bronze 0.2%
182
Green 0.2%
149
Beige 0.2%
142

Mileage Distribution

Most 2009 Mercedes Benz B Class vehicles sit in the blue band. If the vehicle you're looking at is outside it, it's either unusually low or high mileage for its age.

70,610
typical
55,994
low mileage
86,141
high mileage

Half of all 2009 Mercedes Benz B Class vehicles fall between 55,994 and 86,141 miles.

Is the mileage you're seeing normal?
Under 55,994 miles — lower than most. Could be great, or could be a vehicle that rarely moved. Check test frequency and mileage progression in the MOT history.
55,994–86,141 miles — normal for age. This is where most 2009 Mercedes Benz B Classs sit.
Over 116,290 miles — higher than typical. Not necessarily a problem, but check service history and look out for advisory build-up on tyres and brakes.

2009 Mercedes Benz B Class — Still on the Road

Most 2009 Mercedes Benz B Classs are still being driven.

3,801 vehicles still getting MOTs in 2025 — 70% of the peak remain.

5,405 3,801 2014 2025

Based on vehicles from this manufacture year that had at least one MOT test in each calendar year. Data from 2014–2025.
* The 2020 dip reflects the government's COVID-19 MOT exemption, which allowed certificates to be extended by six months — fewer tests were conducted that year.

MOT History Averages

16.4
Avg MOT tests per vehicle
3.85
Avg failures per vehicle
22.4
Avg advisories per vehicle
Other model years — Mercedes Benz B Class: All B Class years → Which year to buy? →
2005 2006 2007 2008 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

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Compare with another model

See how the 2009 Mercedes Benz B Class stacks up against a rival.

Watch for defects — worth knowing