The MOT Files

Known faults, from the test record

Mini One common problems

What fails on the Mini One at MOT, which parts are behind it, and how each model year compares. From 51,292 DVSA test records.

Data updated

Quick answer

The Mini One's most common MOT problems are tyres, bulbs and lamps, wiper blades and washers, recorded in 38.9%, 26.1% and 22.2% of failed tests respectively. By model year, 2022 cars pass most often (90.0%) and 2011 cars least (64.0%), 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 Mini One 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 51,292 cars.

By component

What wears out on a One

Failure items grouped by the part behind them, with the share of failed Mini One 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.Tyres

    38.9% 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” — explained13.4%
    • “A tyre seriously damaged” — explained11.1%
    • “A tyre cords visible or damaged” — explained6.0%
    • “A tyre seriously damaged” — explained5.9%

    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

  2. 2.Bulbs and lamps

    26.1% 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” — explained13.2%
    • “Stop lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning” — explained5.0%
    • “An obligatory rear fog lamp missing, or a front or rear fog lamp inoperative or in the case of a multiple light source more than 1/2 not functioning” — explained3.0%
    • “A rear registration plate lamp or light source missing or inoperative in the case of a single lamp or all lamps” — explained1.8%

    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

  3. 3.Wiper blades and washers

    22.2% of failed tests

    Rubber blades harden and split within a year or two; washer jets block and pumps fail.

    • “Wiper blade missing or obviously not clearing the windscreen” — explained14.0%
    • “Windscreen washers not working or not providing sufficient fluid to clear the windscreen” — explained5.6%
    • “Windscreen washers not working or not providing sufficient fluid to clear the windscreen” — explained2.7%

    Across all cars, wiper blades and washers 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 wiper blades and washers last

  4. 4.Catalytic converter and emissions

    13.7% of failed tests

    Catalysts degrade with age and misfires; a failed emissions reading is usually the catalyst, a lambda sensor or a tired engine.

    • “Lambda coefficient outside the default limits or the range specified by the manufacturer” — explained4.0%
    • “Emissions levels exceed the manufacturer's specified limits” — explained3.1%
    • “Emissions levels exceed the manufacturer's specified limits” — explained1.9%
    • “Emissions levels exceed default limits” — explained1.8%

  5. 5.Brake pads and shoes

    13.4% of failed tests

    Friction material wears with use; the MOT limit is 1.5 mm and a pad that thin is close to metal on metal.

    • “a brake lining or pad worn below 1.5mm” — explained11.1%
    • “Brake lining or pad worn down to wear indicator” — explained2.3%

    Across all cars, brake pads and shoes 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 brake pads and shoes last

  6. 6.Engine management

    7.2% 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” — explained5.6%
    • “Engine MIL illuminated indicating a malfunction” — explained1.5%

  7. 7.Headlamp aim

    7.2% 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” — explained2.9%
    • “The aim of a headlamp is not within limits laid down in the requirements” — explained2.7%
    • “The aim of a headlamp is not within limits laid down in the requirements” — explained1.6%

  8. 8.Brake discs

    7.0% of failed tests

    Discs thin with each pad set and pit or corrode when lightly used; failure is for significant wear, fracture or insecurity, advisory for surface condition.

    • “Brake disc or drum significantly and obviously worn” — explained3.9%
    • “Excessive fluctuation in brake effort through each wheel revolution.” — explained1.6%
    • “Brake disc or drum excessively weakened, insecure or fractured” — explained1.5%

    Across all cars, brake discs failures climb 3-fold between three and fifteen years, peaking at 12–14 years. How long brake discs last

By registration year

One problems by year

MOT pass rate for Mini One 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 2014, up 7.3 points, is larger than wear explains and most likely marks a change in the cars themselves.

201164%
201270%+6.1
201371%+1.3
201479%+7.3
201582%+3.1
201684%+1.9
201784%+0.6
201887%+2.3
201987%+0.8
202086%−0.9
202187%+1.0
202290%+2.5

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 One owners about

Advisories are the same parts a year or two earlier. Share of all Mini One tests carrying an advisory for each.

Go deeper

The rest of the One file

Common questions

What are the most common problems with a Mini One?
Going by what fails the MOT, tyres (recorded in 38.9% of failed tests), bulbs and lamps (recorded in 26.1% of failed tests), and wiper blades and washers (recorded in 22.2% of failed tests). These are the items testers actually record across 51,292 tests, not reports from owners, so they describe what goes wrong at the point where it has to be fixed.
Which Mini One year is the most reliable?
By MOT pass rate, Mini One cars registered in 2022 do best at 90.0% and 2011 cars do worst at 64.0%. 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 2014, up 7.3 points on 2013.
Is the Mini One reliable?
Adjusted for the age and mileage of the cars tested, the Mini One passes 73.9% of MOTs against a national 72.3%. 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 Mini One?
Start with what fails most: tyres, bulbs and lamps, wiper blades and washers. 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