Verdict
The Mercedes-Benz GLB-Class passes its MOT first time on 89.7% of tests, 3.1 points higher than a typical car of the same age and mileage (86.6%). That puts it ahead of 83% of cars on UK roads once age and mileage are taken into account.
By year of first registration, the 2023 GLB-Class does best (beats 88% of cars) and the 2020 worst (beats 79%).
Of its engines, the 1.3 Petrol does best (beats 85%) and the 2.0 Diesel worst (beats 83%).
Better than average on lights & electrics, visibility, suspension.
Watch these weak spots
MOT pass rate by age
First-time pass rate at each MOT by the car’s age in years.
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.
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.
| Engine | Pass rate | Rank | Grade |
|---|---|---|---|
| 1.3 Petrol | 90.3% | Beats 85% | A |
| 2.0 Diesel | 89.0% | Beats 83% | A |
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.
Every MOT area
Share of tests failing on each area, against a typical car of the same age and mileage (black line).
Buying one or MOT due? Check these
- Tyre damage & cracking
Look for cuts, bulges and cracking on both sidewalls of every tyre. - Brake pads
Ask when the pads were last replaced and look for a brake-wear warning on the dash. - Tyre tread depth
Check every tyre, including the inner edge, has at least 3 mm of tread. Uneven wear can point to alignment or suspension problems. - Headlight aim
Park facing a wall at night: both dipped beams should sit level and dip to the left. - Windscreen wipers
Test the washers and wipers: a cheap fix, but a very common MOT fail. - Brake discs
Look through the wheel spokes for scored discs or a heavy rust lip on the edge.
Pass rate by mileage
First-time pass rate by mileage at the test.
Most common MOT failures
| Item | This car | Typical | vs typical |
|---|---|---|---|
| Tyre damage & cracking | 3.7% | 3.8% | 1.0× |
| Brake pads | 1.5% | 1.3% | 1.1× |
| Tyre tread depth | 1.1% | 1.6% | 0.7× |
| Headlight aim | 1.0% | 1.5% | 0.7× |
| Windscreen wipers | 0.8% | 2.0% | 0.4× |
| Horn | 0.4% | 0.1% | 7.1× |
| Windscreen washers | 0.4% | 1.0% | 0.4× |
| Airbag warning light | 0.3% | 0.1% | 2.5× |
| Seat belt condition | 0.3% | 0.2% | 1.3× |
| Wheel nuts & fixings | 0.2% | 0.1% | 2.4× |
Specific defects found
Tester wording for the most frequent failure items, per 1,000 tests.
| Defect | per 1,000 |
|---|---|
| A tyre seriously damaged | 26.8 |
| Tyre tread depth not in accordance with the requirements | 11.0 |
| A tyre cords visible or damaged | 10.8 |
| A brake lining or pad worn below 1.5mm | 10.3 |
| The aim of a headlamp is not within limits laid down in the requirements | 10.0 |
| Wiper blade missing or obviously not clearing the windscreen | 7.9 |
| Brake lining or pad worn down to wear indicator | 5.3 |
| Audible warning inoperative | 4.0 |
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.
2023 Mercedes-Benz GLB-Class1 engine90.4% passA
| Engine | Pass rate | Rank | Grade |
|---|---|---|---|
| 1.3 Petrol | 90.4% | Beats 88% | A |
2022 Mercedes-Benz GLB-Class2 engines90.7% passA
| Engine | Pass rate | Rank | Grade |
|---|---|---|---|
| 1.3 Petrol | 90.8% | Beats 86% | A |
| 2.0 Diesel | 89.7% | Beats 81% | A |
2021 Mercedes-Benz GLB-Class2 engines90.0% passA
| Engine | Pass rate | Rank | Grade |
|---|---|---|---|
| 1.3 Petrol | 90.2% | Beats 85% | A |
| 2.0 Diesel | 89.8% | Beats 87% | A |
2020 Mercedes-Benz GLB-Class2 engines88.5% passB
| Engine | Pass rate | Rank | Grade |
|---|---|---|---|
| 2.0 Diesel | 88.5% | Beats 80% | A |
| 1.3 Petrol | 88.0% | Beats 67% | B |
FAQ
What is the Mercedes-Benz GLB-Class MOT pass rate?
89.7% of MOT tests on the Mercedes-Benz GLB-Class were passed first time, based on 31,121 tests between 2022 and 2026 of cars first registered 2020–2023. A typical car of the same age and mileage passes 86.6% of the time.
Is the Mercedes-Benz GLB-Class reliable?
On MOT results it rates A (excellent): it passes first time more often than a typical car of the same age and mileage and does better than 83% of cars on UK roads. MOT results cover safety and emissions items, not every kind of breakdown.
Which Mercedes-Benz GLB-Class year is best?
Among years with enough data, the 2023 GLB-Class does best for its age and mileage: it beats 88% of cars on UK roads. The 2020 does worst: it beats 79%.
Which Mercedes-Benz GLB-Class engine is best?
Across all years, the 1.3 Petrol does best: it beats 85% of cars on UK roads. The 2.0 Diesel does worst: it beats 83%.
What are the most common MOT failures on the Mercedes-Benz GLB-Class?
The most common failure items are tyre damage & cracking, brake pads, tyre tread depth. Compared with similar cars, horn comes up 7.1× as often.