Mercedes-Benz GLB MOT pass rate & common failures

At a glance

Recorded pass rate

We are not publishing a ranking for the GLB. The examples tested do not cover a wide enough spread of ages and mileages to compare it fairly, and an unadjusted pass rate mostly sorts models by how recently they were bought rather than how well they were built. The failure and advisory patterns below come from the same 12,283 tests and are worth reading on their own terms.

DVSA recorded wording

Most common failure items

Share of failed Mercedes-Benz GLB tests in which each item was recorded. One failed test often lists several items, so these do not sum to 100%.

1. 1.A tyre seriously damaged34.6%

   357 occurrencesTyre damaged or deteriorated explained

2. 2.A brake lining or pad worn below 1.5mm15.8%

   163 occurrencesBrake drum or shoe worn or contaminated explained

3. 3.A tyre cords visible or damaged14.5%

   149 occurrencesTyre ply or cord exposed, or the casing separating explained

4. 4.Tyre tread depth not in accordance with the requirements14.0%

   144 occurrencesTyre worn close to the legal limit explained

5. 5.Wiper blade missing or obviously not clearing the windscreen7.6%

   78 occurrencesWiper or washer not working properly explained

6. 6.Brake lining or pad worn down to wear indicator6.6%

   68 occurrencesBrake drum or shoe worn or contaminated explained

7. 7.Number plate does not conform to the specified requirements5.0%

   52 occurrencesRegistration plate missing, insecure or illegible explained

8. 8.Audible warning inoperative3.8%

   39 occurrencesHorn not working, or of the wrong type explained

9. 9.Brake disc or drum significantly and obviously worn2.9%

   30 occurrencesBrake disc worn, pitted or scored explained

10. 10.A tyre seriously damaged2.9%

    30 occurrencesTyre damaged or deteriorated explained

Warnings without a failure

Most common advisories

Share of all Mercedes-Benz GLB tests carrying each advisory. The denominator differs from the failure list above because an advisory can be issued on a car that passed.

1. 1.Tyre tread depth not in accordance with the requirements16.4%

   2,010 testsTyre worn close to the legal limit explained

2. 2.A tyre seriously damaged13.2%

   1,619 testsTyre damaged or deteriorated explained

3. 3.A brake lining or pad worn below 1.5mm9.9%

   1,212 testsBrake drum or shoe worn or contaminated explained

4. 4.Child Seat fitted not allowing full inspection of adult belt5.9%

   723 tests

5. 5.Brake disc or drum significantly and obviously worn4.5%

   556 testsBrake disc worn, pitted or scored explained

6. 6.Brake disc or drum excessively weakened, insecure or fractured4.0%

   486 testsBrake disc worn, pitted or scored explained

7. 7.A tyre seriously damaged3.1%

   376 testsTyre damaged or deteriorated explained

8. 8.Nail in tyre3.0%

   367 tests

What gets tested

The GLB fleet

Average mileage recorded at test

34,580

Across examples of every age, so this is a description of the fleet rather than an annual figure.

Fuel mix of tested cars

Petrol60.6%

Diesel39.3%

Compare within the range

Other Mercedes-Benz models

• Mercedes-Benz A-Class — 73.3% adjusted
• Mercedes-Benz C-Class — 77.0% adjusted
• Mercedes-Benz E-Class — 78.5% adjusted
• Mercedes-Benz GLA — 82.3% adjusted
• Mercedes-Benz Vito — 71.0% adjusted
• Mercedes-Benz GLC — 85.9% adjusted
• All Mercedes-Benz models →

Common questions

How reliable is the Mercedes-Benz GLB compared with other cars?

We do not publish a comparison for the Mercedes-Benz GLB, because the cars of this model that have been tested do not cover a wide enough range of ages and mileages. Its raw pass rate is 90.0% across 12,283 tests, but comparing a raw rate between models mostly ranks them by how new they are rather than how good they are. The failure and advisory patterns further down the page are still drawn from real tests and are worth reading.

What is the most common MOT failure on a Mercedes-Benz GLB?

The item recorded most often is "A tyre seriously damaged", which appears in 34.6% of failed Mercedes-Benz GLB tests. Because one failed test can list several items, these shares do not add up to 100%.

What do testers most often warn about on a Mercedes-Benz GLB?

The most common advisory is "Tyre tread depth not in accordance with the requirements", noted on 16.4% of all Mercedes-Benz GLB tests. An advisory is not a failure: it flags something that will likely need attention before the next test.

What mileage does a Mercedes-Benz GLB usually have at its MOT?

The average odometer reading recorded at test is 34,580 miles. This is the mileage across all tested examples of every age, not an annual figure, so treat it as a description of the fleet rather than a target for one car.

Are most Mercedes-Benz GLB models petrol or diesel?

Of the Mercedes-Benz GLB cars tested, 61% are petrol, 39% are diesel. Fuel type affects which items tend to fail, particularly emissions and exhaust components.

How this was worked out

Method and limits

Figures come from the DVSA anonymised MOT testing dataset, published under the Open Government Licence. Only class 4 initial tests are counted: retests are excluded so a car appears once, and abandoned tests are excluded entirely. No adjusted rate is shown because this model's tested examples do not cover enough of the national age and mileage range for standardisation to mean anything.

An MOT measures whether a car met a legal standard on the day. It is not a breakdown record, a service history or a running-cost estimate, and a pass rate is a property of a fleet rather than a prediction about one car.

Further reading

Make sense of the numbers

• How to judge reliability from evidence rather than reputation
• What counts as high or low mileage for a car’s age
• The most common MOT failures and how to avoid them
• What to check before buying a used Mercedes-Benz