The MOT Files

Known faults, from the test record

Subaru Impreza common problems

What fails on the Subaru Impreza at MOT, which parts are behind it, and how each model year compares. From 16,713 DVSA test records.

Data updated

Quick answer

The Subaru Impreza's most common MOT problems are catalytic converter and emissions, bulbs and lamps, suspension arms and mountings, recorded in 42.7%, 31.9% and 28.8% of failed tests respectively. By model year, 2004 cars pass most often (77.6%) and 2007 cars least (71.5%), 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 Subaru Impreza 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 16,713 cars.

By component

What wears out on a Impreza

Failure items grouped by the part behind them, with the share of failed Subaru Impreza 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.Catalytic converter and emissions

    42.7% 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” — explained14.6%
    • “Emissions levels exceed the manufacturer's specified limits” — explained10.7%
    • “Emissions levels exceed default limits” — explained6.0%
    • “Emissions levels exceed default limits” — explained5.5%

  2. 2.Bulbs and lamps

    31.9% 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” — explained13.6%
    • “A rear registration plate lamp or light source missing or inoperative in the case of a single lamp or all lamps” — explained4.6%
    • “Stop lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning” — explained3.5%
    • “A headlamp or light source missing, inoperative or more than ½ not functioning in the case of LED” — explained3.5%

    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.Suspension arms and mountings

    28.8% of failed tests

    Arms bend on impact and mountings corrode into the body; a corroded mounting is a structural item and fails as one.

    • “The strength or continuity of the load bearing structure within 30cm of any sub-frame, spring or suspension component mounting (a 'prescribed area') is significantly reduced or inadequately repaired” — explained25.7%
    • “A suspension component excessively damaged or corroded” — explained3.1%

  4. 4.Headlamp aim

    17.1% 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” — explained7.4%
    • “The aim of a headlamp is not within limits laid down in the requirements” — explained5.3%
    • “The aim of a headlamp is not within limits laid down in the requirements” — explained4.5%

  5. 5.Wiper blades and washers

    14.8% 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” — explained6.6%
    • “Windscreen washers not working or not providing sufficient fluid to clear the windscreen” — explained5.1%
    • “Windscreen washers not working or not providing sufficient fluid to clear the windscreen” — explained3.2%

    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

  6. 6.Suspension bushes

    11.0% 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” — explained4.3%
    • “A suspension pin, bush or joint excessively worn” — explained3.6%
    • “A suspension pin, bush or joint excessively worn” — explained3.1%

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

  7. 7.Tyres

    10.8% 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.

    • “A tyre cords visible or damaged” — explained4.1%
    • “Tyre tread depth not in accordance with the requirements” — explained4.0%
    • “A tyre seriously damaged” — explained2.7%

    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

  8. 8.Body and structure

    10.1% of failed tests

    Structural corrosion within 30 cm of a seat belt, suspension or steering mounting fails; it is a disease of age, salt and wet storage.

    • “Vehicle structure corroded to the extent that the rigidity of the assembly is seriously reduced” — explained6.0%
    • “Body, cab or chassis excessively corroded at a mounting point” — explained4.1%

By registration year

Impreza problems by year

MOT pass rate for Subaru Impreza 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. No single step here is large enough to point at a generation change.

200374%
200478%+3.5
200575%−2.9
200675%−0.1
200772%−3.1

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 Impreza owners about

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

Go deeper

The rest of the Impreza file

Common questions

What are the most common problems with a Subaru Impreza?
Going by what fails the MOT, catalytic converter and emissions (recorded in 42.7% of failed tests), bulbs and lamps (recorded in 31.9% of failed tests), and suspension arms and mountings (recorded in 28.8% of failed tests). These are the items testers actually record across 16,713 tests, not reports from owners, so they describe what goes wrong at the point where it has to be fixed.
Which Subaru Impreza year is the most reliable?
By MOT pass rate, Subaru Impreza cars registered in 2004 do best at 77.6% and 2007 cars do worst at 71.5%. 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.
Is the Subaru Impreza reliable?
Adjusted for the age and mileage of the cars tested, the Subaru Impreza passes 78.5% 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 Subaru Impreza?
Start with what fails most: bulbs and lamps, wiper blades and washers, suspension bushes. 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