Model Reports 4 min read Updated 18 Oct 2026

Mercedes-Benz B-Class 2006: reliability & common MOT faults

In 2025, 56 in every 100 first MOTs on a 2006 Mercedes-Benz B-Class were passes. Most common reason for a fail: Drive shaft joints and boots (front).

Summary

The 2006 Mercedes-Benz B-Class follows the pattern of the model years either side.

At a glance

How 1,552 first tests went in 2025.

Passed first time
56 in every 100
Did not pass first time
44 in every 100683 failed first-attempt tests
The typical car
19 yearsabout 99,509 miles
First tests counted
1,552

What failed most often

  1. Drive shaft joints and boots (front)25 in every 100 failed tests
  2. Windscreen washers10 in every 100 failed tests
  3. Handbrake efficiency below minimum (roller test)9 in every 100 failed tests

How we count this. Data: UK MOT open data, 2025. Only Class 4 cars on their first MOT of the year are counted. A car that fails and is fixed at the test station still counts as a fail in the first-attempt rate. These are raw results, not adjusted for age, mileage, or peer mix. The MOT does not test engine or gearbox internals.

Note:

These are patterns across 2006 Mercedes-Benz B-Class vehicles in 2025, not a prediction that any one car will have them. Faults are grouped by part of the car. They come from MOT defect codes, not manufacturer bulletins, recalls or a diagnosis of any one car.

Brakes

One fault: brake efficiency below minimum (roller test), 5.1 times as often as on similar cars.

Figures below are measured across the 675 of 683 failed first attempts (98.8%) that recorded an odometer reading in 2025. Mileage is needed to compare like with like.

We only list faults with at least 20 failures and a rate of about 2.0 times that of similar cars, which keeps one-off results out of the list.

Brake efficiency below minimum (roller test)

Failed on 26 first tests5.1 times as often as similar carsPossible evidence

What it means

Service brake efficiency below the minimum requirement is Major, and efficiency less than half of the required value is graded Dangerous. On a roller brake tester, if more than half of the wheels of a brake system lock, the efficiency requirement for that system counts as met.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Body and structure

One fault: drive shaft joints and boots (front), 3.6 times as often as on similar cars.

Drive shaft joints and boots (front)

Failed on 169 first tests3.6 times as often as similar carsLikely evidence

What it means

A constant velocity boot that is only severely deteriorated is Minor. It is Major once it is missing, split or insecure so that it no longer prevents the ingress of dirt. A transmission joint excessively worn is Major, and graded Dangerous when it is so worn it is likely to fail.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Noise, emissions and leaks

One fault: diesel emissions test (pre-reg turbo rules before 01/07/2008), 2.9 times as often as on similar cars.

Diesel emissions test (pre-reg turbo rules before 01/07/2008)

Failed on 27 first tests2.9 times as often as similar carsPossible evidence

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Lamps and electrical

One fault: individual direction indicators (rear), 2.6 times as often as on similar cars.

Individual direction indicators (rear)

Failed on 44 first tests2.6 times as often as similar carsPossible evidence

What it means

Direction indicators must be amber, though vehicles first used before a set date may have white at the front and red at the rear when the indicators are combined with stop or position lamps, and sequential or dynamic ones are not a reason to fail. A lamp that is missing, inoperative or has more than half of a multiple light source not functioning is graded Major. A flashing rate outside the permitted range is graded Minor.

Also noted as an advisory

Testers also noted it as an advisory, worn but not yet failing, on 35 first tests, 2.8 times as often as on similar cars.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage. Advisories count notes recorded on failed first tests only.

Visibility

One fault: windscreen washers (front), 2.5 times as often as on similar cars.

Windscreen washers (front)

Failed on 49 first tests2.5 times as often as similar carsPossible evidence

What it means

Windscreen washers that are not working, or do not provide sufficient fluid to clear the windscreen, are graded Major. They must provide enough fluid for the wipers to clear the windscreen effectively. Vehicles with an opening windscreen, or some other adequate view to the front, left and right, are not inspected for washers.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Suspension

Two faults. The strongest is the coil spring (rear): 2.4 times as often as on similar cars.

Coil spring (rear)

Failed on 48 first tests2.4 times as often as similar carsPossible evidence

What it means

A missing bump stop rubber is not a reason to fail a coil spring. When the vehicle is jacked and lowered, a spring that does not correctly locate as the suspension returns to its normal running position is rejected as insecurely attached. A missing spring is Major, and graded Dangerous where directional control is affected.

Shock absorbers (front)

Failed on 27 first tests2.0 times as often as similar carsPossible evidence

What it means

Slight seepage that leaves a film of fluid on a shock absorber does not fail it. Severe leakage, or damage so that it does not function, is Major. A shock absorber missing or likely to become detached is graded Dangerous, though a missing one is only rejected if shock absorbers were fitted as standard.

Also noted as an advisory

Testers also noted it as an advisory, worn but not yet failing, on 51 first tests, 2.1 times as often as on similar cars.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage. Advisories count notes recorded on failed first tests only.

Advisories

Other things testers noted as worn or close to failing, more often than on similar cars.

An advisory is a note from the tester about something that has not failed yet. It is an early warning, not a fail. Advisories for the faults above are shown with those faults.

Non-component advisories (rear)

Noted on 50 first tests2.1 times as often as similar carsElevated evidence

Data: UK MOT open data, 2025. Counts cover advisories recorded on failed first tests only, compared with cars of the same age and mileage.

MOT pass rates

How first tests ended, and how the pass rates are counted.

Passed first time
56in every 100
Passed on the first test.
Fixed at the station
8in every 100
Failed, then fixed at the test station the same day.
Failed
36in every 100
Did not pass, and were not fixed at the test station.

First-attempt pass 56.0% of 1,552 first tests (2025): only cars that passed first time count. Official-style pass 64.2%: cars fixed at the test station also count as a pass. The 8 fixed and the 36 not fixed make the 44 in every 100 that did not pass first time.

Petrol and diesel

First testsPassed first time, as tested
Petrol97558
Diesel57753

Figures are in every 100 first tests.

Same model, other years

Passed first time in every 100, all tested in 2025.

4060801002006201020152020Newer cars
406080100200620102020Newer cars

Newer cars are younger, so look for a jump rather than the climb. A year earlier (2024), when these cars were a year younger, 55 in every 100 passed first time.

YearPassed first timeFirst tests
200553 in every 100309
2006 This car56 in every 1001,552
200755 in every 1002,116
200855 in every 1002,936
200958 in every 1003,849
201058 in every 1004,152
201158 in every 1003,257
201269 in every 1005,571
201371 in every 1006,793
201471 in every 1007,934
201576 in every 1005,481
201679 in every 1005,183
201780 in every 1005,502
201883 in every 1003,858
201989 in every 1004,149
202090 in every 1002,786
202192 in every 1001,727
202291 in every 1001,216

FAQs

Short answers about how to read this model-year guide.

The 2006 Mercedes-Benz B-Class follows the pattern of the model years either side. Its main cause of failure was Drive shaft joints and boots (front), about 25 in every 100 failed tests. In 2025, 56.0% of 1,552 first MOTs on the 2006 Mercedes-Benz B-Class passed first time (PRS: items fixed at the station the same day, counted as a fail). The official-style rate including PRS is 64.2%. Among 683 failed first-attempt MOT tests (test year 2025), Brake efficiency below minimum (roller test) appears more often than on similar cars (3.9% of those tests; 26 observed failures; about 5.1× more often than similar cars). There is no single reliability score here; this is a pre-purchase checklist built from DVSA open data, not a guarantee for any individual car.
Ranked by how often they were actually recorded, the items that most often failed a 2006 Mercedes-Benz B-Class at the first attempt were Drive shaft joints and boots (front) (25.0%), Windscreen washers (10.1%) and Handbrake efficiency below minimum (roller test) (9.5%), each as a share of the year's failed first attempts. That is what goes wrong most often on the car. The common faults table shows a different measure: faults that are unusual compared with similar cars.
Among failed first-attempt tests we highlight patterns that appear more often than on similar cars. Top example: Brake efficiency below minimum (roller test) (3.9% of those tests; 26 observed failures; about 5.1× more often than similar cars). These are statistical signals, not a diagnosis of any individual car.
Brake efficiency below minimum (roller test) shows up more often than on similar cars (3.9% of those tests; 26 observed failures; about 5.1× more often than similar cars). That does not prove a design fault. Age, mileage, and how the car was used still matter. Treat it as a pre-purchase checkpoint, not a manufacturer service bulletin.
Common MOT problem areas for the 2006 Mercedes-Benz B-Class include Brake efficiency below minimum (roller test), Drive shaft joints and boots (front), Individual direction indicators (rear). These are the faults that stand out compared with similar cars, not a complete list of what can go wrong on any individual car.
Advisories flag issues noted at the test and are not a fail rate. We show advisory patterns that appear more often than on similar cars among failed first-attempt tests, separate from common failure rows. Use them as early-warning checks, not as a pass/fail score.
This page highlights MOT failure patterns for the 2006 Mercedes-Benz B-Class (registration year) using UK DVSA open data for the selected test year. Patterns are compared with cars of a similar age and mileage. It is a buyer checklist from MOT defect statistics, not a full service history or manufacturer service-bulletin list.
No. MOT tests do not cover engine internals, gearboxes, or many electronic modules. Patterns here come from MOT defect statistics only and should not be read as engine or gearbox reliability scores.

About this data

How this page is built and what it can (and can't) say.

These figures come from UK MOT open data for this model year. We surface common failure patterns against similar cars, not a full reliability score, and not a pass/fail verdict on any individual vehicle.

2024 2025

What we include

UK Class 4 cars only. Normal MOT tests (not retests); first test per vehicle per calendar year; results pass, PRS, or fail.

Same-day repairs

PRS means the car failed items that were fixed at the test station and then passed the same day. We count PRS as a first-attempt fail in headline rates so same-day repairs do not hide problems.

How we compare

We compare this model year with other Class 4 cars of similar age and mileage in the same test year. This model family is left out of the peer group so the car is not measured against itself.

What this does not cover

  • MOTs do not cover engine internals, gearboxes, or many electronics; this is not a full reliability score.
  • Common faults come from MOT defect stats, not manufacturer TSBs or recalls.
  • Age and mileage matching reduces, but does not remove, differences in how cars were used and maintained.
  • If the data for a car is too thin to say anything useful, we say so rather than guess.

Contains public sector information licensed under the Open Government Licence v3.0.

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