Mercedes-Benz M-Class MOT Failure Rate & Common Faults
We analysed 36,671 MOT tests on the Mercedes-Benz M-Class carried out in 2023. 29% failed at the first attempt, which is roughly in line with the 29% average across all cars in the same data. Put another way, about 7 in 10 M-Classes passed first time.
Results cover cars first registered from 1999 to 2015. Compared with other cars of the same age, 2013 models did best (81% passed, +12.6 points against the average for 10-year-old cars), while 1999 models fared worst (59%, −3.9 points). Tested cars had covered 107,403 miles on average, against 73,145 across all cars.
The most common reason for failure was lights and electrics, found on 12.7% of tests (roughly in line with the 11.3% seen across all cars). The single most frequent fault was "not working", on 7.6% of tests.
- MOT tests analysed
- 36,671
- First-time pass rate
- 71%
- All cars: 71%
- Versus all cars
- −0.1 points
- Average mileage at test
- 107,403
- All cars: 73,145
Checking a particular M-Class?
See its own MOT history, advisories and mileage for free.
M-Class MOT pass rate by year
Older cars fail more often, so each year is compared with all cars of the same age. Bars above the dashed line did better than average for their age.
| First registered | Tests | Pass rate | All cars, same age | Difference | Avg mileage |
|---|---|---|---|---|---|
| 2015 | 3,220 | 85% | 75% | +9.2 points | 70,081 |
| 2014 | 3,912 | 82% | 72% | +9.9 points | 80,029 |
| 2013 | 4,345 | 81% | 68% | +12.6 points | 90,313 |
| 2012 | 2,682 | 77% | 66% | +11.6 points | 95,510 |
| 2011 | 2,845 | 72% | 63% | +8.6 points | 103,658 |
| 2010 | 2,949 | 68% | 60% | +7.4 points | 111,671 |
| 2009 | 2,300 | 68% | 59% | +8.9 points | 117,404 |
| 2008 | 2,657 | 66% | 57% | +9.0 points | 123,486 |
| 2007 | 2,603 | 66% | 57% | +9.4 points | 128,089 |
| 2006 | 2,295 | 67% | 56% | +10.5 points | 129,835 |
| 2005 | 1,256 | 59% | 56% | +2.7 points | 128,577 |
| 2004 | 1,733 | 58% | 56% | +1.6 points | 130,532 |
| 2003 | 1,263 | 56% | 57% | −0.4 points | 130,719 |
| 2002 | 1,151 | 61% | 58% | +3.1 points | 131,002 |
| 2001 | 632 | 63% | 59% | +4.2 points | 134,806 |
| 2000 | 524 | 60% | 61% | −0.8 points | 134,748 |
| 1999 | 256 | 59% | 62% | −3.9 points | 131,274 |
Why the Mercedes-Benz M-Class fails its MOT
The share of tests with at least one failure in each area, compared with all cars.
| Failure area | M-Class | All cars |
|---|---|---|
| Lights and electrics | 12.7% | 11.3% |
| Brakes | 8.3% | 6.8% |
| Suspension | 8.2% | 8.9% |
| Tyres | 5.3% | 6.3% |
| Noise, emissions and leaks | 4.1% | 3.1% |
| Body and structure | 3.2% | 3.5% |
| Visibility | 3.1% | 4.8% |
| Steering | 2.2% | 1.8% |
| Seatbelts and airbags | 1.4% | 1.0% |
| Road Wheels | 0.7% | 0.4% |
Top 10 specific failure reasons
- 1not working7.6%
- 2fractured or broken5.1%
- 3inoperative or indicates a malfunction2.2%
- 4tread depth below requirements of 1.6mm2.0%
- 5efficiency below requirements2.0%
- 6excessively corroded1.9%
- 7less than 1.5 mm thick1.5%
- 8has ply or cords exposed1.4%
- 9not working on dipped beam1.4%
- 10constant velocity boot split or insecure, no longer prevents the ingress of dirt1.3%
Common M-Class MOT advisories
Advisories don't cause a fail, but they show what's wearing out. On a used M-Class, check whether these have been dealt with. Read our guide to MOT advisories.
| Advisory | Area | Share of tests |
|---|---|---|
| tread depth below requirements of 1.6mm | Tyres | 17.2% |
| leaking excessively from engine | Noise, emissions and leaks | 14.8% |
| excessively corroded | Brakes | 10.9% |
| less than 1.5 mm thick | Brakes | 7.4% |
| in such a condition that it is seriously weakened | Brakes | 6.3% |
| pin or bush excessively worn | Suspension | 5.5% |
| has a tear, caused by separation or partial failure of its structure | Tyres | 3.9% |
| ball joint excessively worn | Suspension | 3.4% |
| corroded so that its cross sectional area is reduced and seriously weakened | Suspension | 3.4% |
| significantly and obviously worn | Brakes | 3.0% |
Tips to help your M-Class pass
Based on where M-Classes most often fail. For a full list, use our pre-MOT checklist.
Lights and electrics · 12.7% of M-Class tests
Walk round every light
With a helper, check headlights on dipped and main beam, sidelights, brake lights, indicators, the rear fog light and the number plate lamp. Replace blown bulbs in pairs and make sure no lenses are cracked.
Brakes · 8.3% of M-Class tests
Don't ignore brake warning signs
Grinding, squealing, a soft pedal or the car pulling to one side under braking are all worth investigating before the MOT. Check whether the last test noted worn pads or discs; if so, they may now be below the limit.
Compare with other models
Is the M-Class ULEZ compliant? See the Mercedes-Benz M-Class ULEZ check, or view all Mercedes-Benz models.
Other Mercedes-Benz models
Models with similar pass rates
About this data
Based on 36,671 first MOT tests of the Mercedes-Benz M-Class carried out in 2023.
Source: DVSA anonymised MOT test data (contains public sector information licensed under the Open Government Licence v3.0). First attempts on cars only; “pass rate” means passing first time. Averages cover all 32,735,164 cars tested (71% passed), and years with under 50 tests are hidden.
Learn more about how our data works.
Frequently asked questions
Answers from 36,671 first MOT tests of the Mercedes-Benz M-Class.
What is the Mercedes-Benz M-Class MOT failure rate?
In our data, 29% of 36,671 first MOT attempts on the Mercedes-Benz M-Class ended in a fail, compared with 29% for all cars.
What is the most common reason a Mercedes-Benz M-Class fails its MOT?
The most common failure areas were lights and electrics (12.7% of tests), brakes (8.3% of tests), suspension (8.2% of tests).
Which M-Class year has the best MOT pass rate?
Allowing for age, 2013 cars performed best: 81% passed first time, +12.6 points against the average for 10-year-old cars. The weakest was 1999, at 59% (−3.9 points).
How many miles had a typical Mercedes-Benz M-Class covered at its MOT?
The average was 107,403 miles, against 73,145 for all cars tested. 2015 cars averaged 70,081 miles and 1999 cars 131,274.
What is the most common MOT advisory on the Mercedes-Benz M-Class?
"tread depth below requirements of 1.6mm" was recorded on 17.2% of tests, in the tyres area. 5.3% of M-Classes failed in that area too.
How can I check a specific M-Class's MOT history?
Enter its registration in our free MOT check. Across the 36,671 M-Classes in our data, first-time pass rates ranged from 56% to 85% by year, so one car's own record says more than the average.
Related guides
- MOT · 6 min readPre-MOT checklist: 20 things to check yourself before the testTwenty quick checks, grouped by area, that you can do on your driveway in under half an hour. No tools beyond a coin and a helper needed for most.Read the guide
- MOT · 6 min readDangerous, major and minor MOT defects explainedSince 2018, every fault found at an MOT goes into one of four categories. Knowing the difference tells you whether you can drive home, and what to fix first.Read the guide
- MOT · 6 min readThe most common reasons cars fail their MOT (and how to avoid them)Lights alone failed 11.3% of cars at their 2023 MOT, more than any other area. The common failure areas, ranked, and the driveway checks that prevent them.Read the guide
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