The MOT Files

Known faults, from the test record

Mercedes-Benz ML common problems

What fails on the Mercedes-Benz ML at MOT, which parts are behind it, and how each model year compares. From 29,100 DVSA test records.

Data updated

Quick answer

The Mercedes-Benz ML's most common MOT problems are bulbs and lamps, tyres, coil springs, recorded in 35.0%, 30.9% and 23.4% of failed tests respectively. By model year, 2015 cars pass most often (81.6%) and 2006 cars least (67.2%), though most of that gap is age. Every figure here is what testers recorded, not what owners reported.

A “common problems” list is usually a forum thread: whoever had the worst day writes the longest post. This one is built the other way, from every Mercedes-Benz ML that took an MOT last year and what the tester wrote down. It cannot see breakdowns, electrical gremlins or a gearbox that hunts, because the test does not check those. What it can see, it sees across 29,100 cars.

By component

What wears out on a ML

Failure items grouped by the part behind them, with the share of failed Mercedes-Benz ML tests recording each. A part can carry several DVSA wordings; they are listed beneath. One failed test often lists several items, so shares do not sum to 100%.

  1. 1.Bulbs and lamps

    35.0% of failed tests

    Filament bulbs simply expire; the cheapest and most avoidable failure on the test, and one of the most recorded.

    • “A lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning” — explained9.7%
    • “Stop lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning” — explained8.1%
    • “A direction indicator lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning” — explained6.0%
    • “A headlamp or light source missing, inoperative or more than ½ not functioning in the case of LED” — explained4.0%

    Across all cars, bulbs and lamps failures climb 15-fold between three and fifteen years, peaking at 15+ years. How long bulbs and lamps last

  2. 2.Tyres

    30.9% of failed tests

    Tread wears with every mile and sidewalls age and take kerb damage; the legal minimum is 1.6 mm across the central three-quarters.

    • “Tyre tread depth not in accordance with the requirements” — explained11.7%
    • “A tyre cords visible or damaged” — explained9.6%
    • “A tyre seriously damaged” — explained7.1%
    • “A tyre seriously damaged” — explained2.5%

    Across all cars, tyres failures run at a similar rate at every age, because they are replaced on a cycle rather than wearing out with the car. How long tyres last

  3. 3.Coil springs

    23.4% of failed tests

    Springs fatigue and corrode where the coating chips, then snap, often at the bottom coil; potholes and salt accelerate it.

    • “A spring or spring component fractured or seriously weakened” — explained23.4%

    Across all cars, coil springs failures climb 20-fold between three and fifteen years, peaking at 12–14 years. How long coil springs last

  4. 4.Parking brake

    12.3% of failed tests

    Cables stretch and seize, rear shoes and adjusters wear; efficiency is measured on the roller tester against the vehicle's weight.

    • “Parking brake efficiency below minimum requirement” — explained5.4%
    • “Parking brake efficiency below minimum requirement” — explained2.4%
    • “Parking brake inoperative on one side” — explained2.3%
    • “Parking brake efficiency less than 50% of the required value” — explained2.2%

  5. 5.Brake pipes

    9.9% of failed tests

    Steel pipes under the car corrode from salt and moisture, fastest on cars kept outside in wet or coastal areas; failure is for excessive corrosion or damage.

    • “Brake pipe damaged or excessively corroded” — explained8.2%
    • “Leaking brake pipe or connection on a hydraulic system” — explained1.7%

    Across all cars, brake pipes failures climb from nothing between three and fifteen years, peaking at 15+ years. How long brake pipes last

  6. 6.Headlamp aim

    9.6% of failed tests

    Aim drifts with sagging suspension, a knocked lamp or a botched bulb change; adjustment, not a part.

    • “The aim of a headlamp is not within limits laid down in the requirements” — explained5.8%
    • “The aim of a headlamp is not within limits laid down in the requirements” — explained2.0%
    • “The aim of a headlamp is not within limits laid down in the requirements” — explained1.8%

  7. 7.Engine management

    8.8% of failed tests

    The MIL lamp lit is a failure in itself, whatever the stored code; the fault codes section explains what lies behind it.

    • “Engine MIL illuminated indicating a malfunction” — explained6.2%
    • “Engine MIL illuminated indicating a malfunction” — explained2.6%

  8. 8.Suspension bushes

    7.8% of failed tests

    Rubber bushes in arms and links perish and split with age and load; the most recorded suspension item on the test.

    • “A suspension pin, bush or joint excessively worn” — explained3.4%
    • “A suspension pin, bush or joint excessively worn” — explained2.5%
    • “A suspension pin, bush or joint excessively worn” — explained1.9%

    Across all cars, suspension bushes failures climb 20-fold between three and fifteen years, peaking at 15+ years. How long suspension bushes last

By registration year

ML problems by year

MOT pass rate for Mercedes-Benz ML cars by the year they were first registered, from years with at least 1,000 tests. Every car in a row is the same age, so the rate is raw. Neighbouring years differ by a year of wear — a step of a point or two is age. The step at 2012, up 6.2 points, is larger than wear explains and most likely marks a change in the cars themselves.

200667%
200768%+0.4
200868%+0.6
200967%−0.9
201068%+0.7
201170%+2.1
201276%+6.2
201380%+3.4
201480%+0.0
201582%+1.8

Last column: change on the previous year, in points. Years registered within the last three years have not yet been tested and are not shown.

Before it fails

What testers warn ML owners about

Advisories are the same parts a year or two earlier. Share of all Mercedes-Benz ML tests carrying an advisory for each.

Go deeper

The rest of the ML file

Common questions

What are the most common problems with a Mercedes-Benz ML?
Going by what fails the MOT, bulbs and lamps (recorded in 35.0% of failed tests), tyres (recorded in 30.9% of failed tests), and coil springs (recorded in 23.4% of failed tests). These are the items testers actually record across 29,100 tests, not reports from owners, so they describe what goes wrong at the point where it has to be fixed.
Which Mercedes-Benz ML year is the most reliable?
By MOT pass rate, Mercedes-Benz ML cars registered in 2015 do best at 81.6% and 2006 cars do worst at 67.2%. Most of that ordering is simply age — newer cars pass more — so read the year table for steps larger than a couple of points between neighbouring years; those mark a change in the cars rather than the calendar. The largest such step is at 2012, up 6.2 points on 2011.
Is the Mercedes-Benz ML reliable?
The Mercedes-Benz ML passes 72.2% of MOTs unadjusted; its fleet is too narrow in age or mileage for a fair national comparison. An MOT measures roadworthiness on the day rather than breakdowns or running costs, so this is a reliability measure in the narrow sense: how often the car meets the legal standard, and what stops it.
What should I check when buying a used Mercedes-Benz ML?
Start with what fails most: bulbs and lamps, tyres, coil springs. Then read the car's own MOT history for advisories carried year to year without repair — the model tells you what to expect, the history tells you whether this owner dealt with it.

Analysis built from DVSA data of