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Mercedes-Benz B-Class reliability

B · Good

MOT pass rates and common problems from 580,197 MOT tests of cars first registered 2005–2021.

Jump to: YearsEnginesCommon failures
73.6%pass first time
+2.1 ptsvs typical car
Beats 62%of cars
580,197MOT tests

Verdict

The Mercedes-Benz B-Class passes its MOT first time on 73.6% of tests, 2.1 points higher than a typical car of the same age and mileage (71.5%). That puts it ahead of 62% of cars on UK roads once age and mileage are taken into account.

By year of first registration, the 2013 B-Class does best (beats 77% of cars) and the 2011 worst (beats 37%).

Of its engines, the 1.6 Petrol does best (beats 79%) and the 1.5 Petrol worst (beats 47%).

Better than average on visibility, steering.

Watch these weak spots

Seat belts & airbags1.6×as often as a typical car
Indicator side repeaters2.8×as often as a typical car
Brake pipes2.1×as often as a typical car
Drive shaft (CV) joints1.6×as often as a typical car

MOT pass rate by age

First-time pass rate at each MOT by the car’s age in years.

50%60%70%80%90%100%3456789101112131415161718192089%86%81%75%68%63%57%56%56%
Mercedes-Benz B-ClassTypical car, same age & mileage

Best and worst years

By year of first registration, ranked against all cars on UK roads after adjusting for age and mileage. Green = better than half of cars.

2005
Beats 60%
2006
Beats 55%
2007
Beats 54%
2008
Beats 52%
2009
Beats 55%
2010
Beats 50%
2011
Beats 37%
2012
Beats 74%
2013
Beats 77%
2014
Beats 69%
2015
Beats 73%
2016
Beats 68%
2017
Beats 60%
2018
Beats 56%
2019
Beats 79%
2020
Beats 84%
2021
Beats 83%

Engines

All years, most common first. Grades compare each car with cars of the same age and mileage (A = best 20% of cars on UK roads, E = worst 20%), so an older or higher-mileage car can grade above one with a higher pass rate.

EngineYearsTestsPass rateRankGrade
2.0 Diesel2005–2021118,82262.4%Beats 52%C
1.5 Diesel2013–2019118,00779.7%Beats 63%B
1.8 Diesel2012–201596,16875.6%Beats 74%B
1.5 Petrol2006–201167,67861.7%Beats 47%C
1.6 Petrol2012–201966,51583.6%Beats 79%B
2.1 Diesel2013–201857,49883.5%Beats 70%B
1.7 Petrol2005–201024,64662.0%Beats 60%C
1.3 Petrol2019–202119,78990.8%Beats 83%A
2.0 Petrol2005–20109,39063.4%Beats 63%B
Electric2016–20161,68482.9%Beats 46%C

Where it fails

Each area compared with a typical car of the same age and mileage, in points of pass rate. Tap or hover an area to see what to check.

Exhaust: 2.7% of tests fail on emissions & leaks, against 2.7% for a typical car of the same age and mileage. Listen for a blowing exhaust at start-up and look underneath for oil or fluid leaks.Suspension: 7.5% of tests fail on suspension, against 8.8% for a typical car of the same age and mileage. Listen for knocks over speed bumps and push each corner down: it should settle at once.Lights: 10.1% of tests fail on lights & electrics, against 11.2% for a typical car of the same age and mileage. Walk round the car with every light on, including brake, fog and number plate lights.Tyres: 6.7% of tests fail on tyres, against 6.3% for a typical car of the same age and mileage. Check the tread on every tyre, including the inner edge, and look for cuts or bulges.Brakes: 5.9% of tests fail on brakes, against 6.3% for a typical car of the same age and mileage. Brake firmly on the test drive: the car should stop straight with no pulsing or grinding.Lights: 10.1% of tests fail on lights & electrics, against 11.2% for a typical car of the same age and mileage. Walk round the car with every light on, including brake, fog and number plate lights.Lights+1.1 ptsTyres: 6.7% of tests fail on tyres, against 6.3% for a typical car of the same age and mileage. Check the tread on every tyre, including the inner edge, and look for cuts or bulges.Tyres−0.4 ptsBrakes: 5.9% of tests fail on brakes, against 6.3% for a typical car of the same age and mileage. Brake firmly on the test drive: the car should stop straight with no pulsing or grinding.Brakes+0.4 ptsSuspension: 7.5% of tests fail on suspension, against 8.8% for a typical car of the same age and mileage. Listen for knocks over speed bumps and push each corner down: it should settle at once.Suspension+1.3 ptsExhaust: 2.7% of tests fail on emissions & leaks, against 2.7% for a typical car of the same age and mileage. Listen for a blowing exhaust at start-up and look underneath for oil or fluid leaks.Exhaust0.0 ptsSuspension: 7.5% of tests fail on suspension, against 8.8% for a typical car of the same age and mileage. Listen for knocks over speed bumps and push each corner down: it should settle at once.Brakes: 5.9% of tests fail on brakes, against 6.3% for a typical car of the same age and mileage. Brake firmly on the test drive: the car should stop straight with no pulsing or grinding.Tyres: 6.7% of tests fail on tyres, against 6.3% for a typical car of the same age and mileage. Check the tread on every tyre, including the inner edge, and look for cuts or bulges.Lights: 10.1% of tests fail on lights & electrics, against 11.2% for a typical car of the same age and mileage. Walk round the car with every light on, including brake, fog and number plate lights.Exhaust: 2.7% of tests fail on emissions & leaks, against 2.7% for a typical car of the same age and mileage. Listen for a blowing exhaust at start-up and look underneath for oil or fluid leaks.Lights: 10.1% of tests fail on lights & electrics, against 11.2% for a typical car of the same age and mileage. Walk round the car with every light on, including brake, fog and number plate lights.Lights+1.1 ptsTyres: 6.7% of tests fail on tyres, against 6.3% for a typical car of the same age and mileage. Check the tread on every tyre, including the inner edge, and look for cuts or bulges.Tyres−0.4 ptsBrakes: 5.9% of tests fail on brakes, against 6.3% for a typical car of the same age and mileage. Brake firmly on the test drive: the car should stop straight with no pulsing or grinding.Brakes+0.4 ptsSuspension: 7.5% of tests fail on suspension, against 8.8% for a typical car of the same age and mileage. Listen for knocks over speed bumps and push each corner down: it should settle at once.Suspension+1.3 ptsExhaust: 2.7% of tests fail on emissions & leaks, against 2.7% for a typical car of the same age and mileage. Listen for a blowing exhaust at start-up and look underneath for oil or fluid leaks.Exhaust0.0 pts
Better than typicalTypicalWorse than typical
Tyres: 6.7% of tests fail on tyres, against 6.3% for a typical car of the same age and mileage. Check the tread on every tyre, including the inner edge, and look for cuts or bulges.

Every MOT area

Share of tests failing on each area, against a typical car of the same age and mileage (black line).

Lights & electrics
10.1% vs 11.2%
Suspension
7.5% vs 8.8%
Tyres
6.7% vs 6.3%
Brakes
5.9% vs 6.3%
Visibility
3.7% vs 4.7%
Body & structure
2.8% vs 3.0%
Emissions & leaks
2.7% vs 2.7%
Seat belts & airbags
1.3% vs 0.8%
Wheels
0.7% vs 0.3%
Steering
0.3% vs 1.7%

Buying one or MOT due? Check these

  • Indicator side repeaters 2.8× typical
    Walk around with the lights on: bulb failures are the easiest MOT fails to avoid.
  • Engine warning light 1.6× typical
    The engine warning light should come on with the ignition and go out once the engine starts. If it stays on, get the fault codes read before you buy.
  • Tyre damage & cracking
    Look for cuts, bulges and cracking on both sidewalls of every tyre.
  • Coil springs
    Look behind each wheel for a snapped coil (often the bottom one) and listen for clunks over bumps.
  • Headlight aim
    Park facing a wall at night: both dipped beams should sit level and dip to the left.
  • Windscreen washers
    Test the washers and wipers: a cheap fix, but a very common MOT fail.

Pass rate by mileage

First-time pass rate by mileage at the test.

50%60%70%80%90%100%0k10k20k30k40k50k60k70k80k90k100k110k120k130k140k150k94%88%80%72%64%59%57%54%
Mercedes-Benz B-ClassTypical car

Most common MOT failures

ItemThis carTypicalvs typical
Tyre damage & cracking4.8%3.5%1.4×
Coil springs3.1%2.7%1.2×
Headlight aim2.7%3.1%0.9×
Windscreen washers2.3%2.1%1.1×
Drive shaft (CV) joints1.9%1.2%1.6×
Brake pads1.9%1.9%1.0×
Number plate lights1.9%1.3%1.5×
Headlight bulbs & units1.7%2.0%0.8×
Tyre tread depth1.6%2.5%0.7×
Suspension ball joints1.6%1.4%1.1×

Specific defects found

Tester wording for the most frequent failure items, per 1,000 tests.

Defectper 1,000
A spring or spring component fractured or seriously weakened31.4
A tyre seriously damaged30.2
The aim of a headlamp is not within limits laid down in the requirements27.0
Windscreen washers not working or not providing sufficient fluid to clear the windscreen23.0
A suspension joint dust cover missing or no longer prevents the ingress of dirt etc20.0
A suspension pin, bush or joint excessively worn19.9
Engine MIL illuminated indicating a malfunction19.9
A transmission shaft constant velocity joint boot missing or no longer prevents the ingress of dirt etc19.8
Check another car

Pick a make and model to see its MOT pass rate, best and worst years and weak spots.

Every year and engine

Tap a year to see its engines. Grades compare each car with cars of the same age and mileage (A = best 20% of cars on UK roads, E = worst 20%), so an older or higher-mileage car can grade above one with a higher pass rate.

2021 Mercedes-Benz B-Class2 engines91.3% passA
EngineTestsPass rateRankGrade
1.3 Petrol2,62591.4%Beats 81%A
2.0 Diesel1,47291.1%Beats 87%A
2020 Mercedes-Benz B-Class2 engines91.0% passA
EngineTestsPass rateRankGrade
1.3 Petrol6,76591.0%Beats 81%A
2.0 Diesel3,91590.9%Beats 89%A
2019 Mercedes-Benz B-Class4 engines89.7% passB
EngineTestsPass rateRankGrade
1.3 Petrol10,39990.5%Beats 84%A
2.0 Diesel5,44589.1%Beats 79%B
1.6 Petrol1,88288.5%Beats 62%B
1.5 Diesel1,84887.9%Beats 69%B
2018 Mercedes-Benz B-Class3 engines86.0% passC
EngineTestsPass rateRankGrade
1.6 Petrol11,47488.1%Beats 66%B
1.5 Diesel6,12483.9%Beats 47%C
2.1 Diesel5,69084.0%Beats 40%C
2017 Mercedes-Benz B-Class3 engines84.4% passB
EngineTestsPass rateRankGrade
1.5 Diesel16,71182.6%Beats 49%C
2.1 Diesel15,26484.7%Beats 63%B
1.6 Petrol6,29388.3%Beats 78%B
2016 Mercedes-Benz B-Class4 engines83.6% passB
EngineTestsPass rateRankGrade
1.5 Diesel17,24282.3%Beats 64%B
2.1 Diesel16,34683.7%Beats 70%B
1.6 Petrol6,53687.0%Beats 79%B
Electric1,68482.9%Beats 46%C
2015 Mercedes-Benz B-Class4 engines82.2% passB
EngineTestsPass rateRankGrade
1.5 Diesel24,88280.6%Beats 66%B
2.1 Diesel16,07183.1%Beats 79%B
1.6 Petrol6,72986.7%Beats 87%A
1.8 Diesel1,42979.1%Beats 60%C
2014 Mercedes-Benz B-Class4 engines78.4% passB
EngineTestsPass rateRankGrade
1.5 Diesel44,08677.1%Beats 64%B
1.8 Diesel17,57879.2%Beats 75%B
1.6 Petrol7,97182.9%Beats 83%A
2.1 Diesel2,68681.2%Beats 83%A
2013 Mercedes-Benz B-Class4 engines77.0% passB
EngineTestsPass rateRankGrade
1.8 Diesel42,65776.6%Beats 77%B
1.6 Petrol11,70980.6%Beats 82%A
1.5 Diesel7,11474.0%Beats 67%B
2.1 Diesel1,44175.7%Beats 75%B
2012 Mercedes-Benz B-Class3 engines73.8% passB
EngineTestsPass rateRankGrade
1.8 Diesel34,50472.5%Beats 71%B
1.6 Petrol13,92177.1%Beats 80%B
2.0 Diesel2,10171.7%Beats 72%B
2011 Mercedes-Benz B-Class2 engines63.7% passD
EngineTestsPass rateRankGrade
2.0 Diesel15,72362.9%Beats 38%D
1.5 Petrol14,50464.5%Beats 35%D
2010 Mercedes-Benz B-Class4 engines63.4% passC
EngineTestsPass rateRankGrade
2.0 Diesel20,18962.2%Beats 50%C
1.5 Petrol17,25663.9%Beats 49%C
1.7 Petrol2,22267.2%Beats 56%C
2.0 Petrol1,72567.8%Beats 60%C
2009 Mercedes-Benz B-Class4 engines61.7% passC
EngineTestsPass rateRankGrade
2.0 Diesel21,05060.5%Beats 55%C
1.5 Petrol14,18162.0%Beats 53%C
1.7 Petrol4,42865.4%Beats 62%B
2.0 Petrol1,56864.2%Beats 57%C
2008 Mercedes-Benz B-Class3 engines58.8% passC
EngineTestsPass rateRankGrade
2.0 Diesel18,86758.1%Beats 53%C
1.5 Petrol10,46758.7%Beats 48%C
1.7 Petrol5,19061.5%Beats 56%C
2007 Mercedes-Benz B-Class4 engines58.4% passC
EngineTestsPass rateRankGrade
2.0 Diesel15,72957.0%Beats 52%C
1.5 Petrol6,56757.7%Beats 47%C
1.7 Petrol4,82760.7%Beats 59%C
2.0 Petrol2,21565.9%Beats 75%B
2006 Mercedes-Benz B-Class4 engines56.9% passC
EngineTestsPass rateRankGrade
2.0 Diesel11,44054.7%Beats 51%C
1.7 Petrol6,37359.7%Beats 61%B
1.5 Petrol4,70357.0%Beats 52%C
2.0 Petrol2,84759.7%Beats 60%B
2005 Mercedes-Benz B-Class3 engines57.1% passC
EngineTestsPass rateRankGrade
2.0 Diesel2,89154.2%Beats 53%C
1.7 Petrol1,60660.5%Beats 65%B
2.0 Petrol1,03559.8%Beats 64%B

FAQ

What is the Mercedes-Benz B-Class MOT pass rate?

73.6% of MOT tests on the Mercedes-Benz B-Class were passed first time, based on 580,197 tests between 2018 and 2026 of cars first registered 2005–2021. A typical car of the same age and mileage passes 71.5% of the time.

Is the Mercedes-Benz B-Class reliable?

On MOT results it rates B (good): it passes first time more often than a typical car of the same age and mileage and does better than 62% of cars on UK roads. MOT results cover safety and emissions items, not every kind of breakdown.

Which Mercedes-Benz B-Class year is best?

Among years with enough data, the 2013 B-Class does best for its age and mileage: it beats 77% of cars on UK roads. The 2011 does worst: it beats 37%.

Which Mercedes-Benz B-Class engine is best?

Across all years, the 1.6 Petrol does best: it beats 79% of cars on UK roads. The 1.5 Petrol does worst: it beats 47%.

What are the most common MOT failures on the Mercedes-Benz B-Class?

The most common failure items are tyre damage & cracking, coil springs, headlight aim. Compared with similar cars, indicator side repeaters comes up 2.8× as often.

How we calculate this. We use official MOT results for cars tested in Great Britain from 2018 to 2026. Each car is compared with typical cars of the same age and mileage, so old and new cars are judged fairly; “pts” are percentage points above or below them. Differences also reflect how cars are used and maintained, not only how they are built.