The MOT Files

Known faults, from the test record

BMW I3 common problems

What fails on the BMW I3 at MOT, which parts are behind it, and how each model year compares. From 26,183 DVSA test records.

Data updated

Quick answer

The BMW I3's most common MOT problems are tyres, wiper blades and washers, coil springs, recorded in 70.4%, 19.1% and 10.4% of failed tests respectively. By model year, 2021 cars pass most often (91.0%) and 2014 cars least (79.4%), 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 BMW I3 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 26,183 cars.

By component

What wears out on a I3

Failure items grouped by the part behind them, with the share of failed BMW I3 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

    70.4% 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 seriously damaged” — explained26.1%
    • “Tyre tread depth not in accordance with the requirements” — explained22.7%
    • “A tyre cords visible or damaged” — explained8.8%
    • “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.Wiper blades and washers

    19.1% 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” — explained9.1%
    • “Windscreen washers not working or not providing sufficient fluid to clear the windscreen” — explained8.2%
    • “Windscreen washers not working or not providing sufficient fluid to clear the windscreen” — explained1.9%

    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

  3. 3.Coil springs

    10.4% 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” — explained10.4%

    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.Bulbs and lamps

    9.4% of failed tests

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

    • “A direction indicator lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning” — explained5.9%
    • “A headlamp or light source missing, inoperative or more than ½ not functioning in the case of LED” — explained1.2%
    • “A direction indicator lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning” — explained1.0%
    • “Headlamp levelling device inoperative” — explained0.8%

    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

  5. 5.Headlamp aim

    5.8% 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” — explained2.7%
    • “The aim of a headlamp is not within limits laid down in the requirements” — explained2.5%
    • “The aim of a headlamp is not within limits laid down in the requirements” — explained0.6%

  6. 6.Brake discs

    5.3% 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” — explained2.3%
    • “Excessive fluctuation in brake effort through each wheel revolution.” — explained1.5%
    • “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

  7. 7.Wheels and fixings

    4.3% of failed tests

    Rims crack or distort on potholes and kerbs; a missing or loose wheel nut is a fitting error rather than wear.

    • “A wheel with a loose or missing wheel nut, bolt or stud” — explained1.7%
    • “Any fracture or welding defect on a wheel” — explained1.4%
    • “A wheel badly distorted or wear between wheel and hub at spigot mounting” — explained1.2%

  8. 8.Airbags

    3.5% of failed tests

    The warning lamp lit is a failure; usually a seat sensor, a connector under the seat or a clock spring.

    • “An SRS malfunction indicator lamp (MIL) indicates a system malfunction” — explained3.5%

By registration year

I3 problems by year

MOT pass rate for BMW I3 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 2018, up 4.5 points, is larger than wear explains and most likely marks a change in the cars themselves.

201479%
201582%+2.7
201682%−0.3
201784%+2.4
201889%+4.5
201988%−0.3
202089%+0.2
202191%+2.4
202288%−2.8

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 I3 owners about

Advisories are the same parts a year or two earlier. Share of all BMW I3 tests carrying an advisory for each.

Go deeper

The rest of the I3 file

Common questions

What are the most common problems with a BMW I3?
Going by what fails the MOT, tyres (recorded in 70.4% of failed tests), wiper blades and washers (recorded in 19.1% of failed tests), and coil springs (recorded in 10.4% of failed tests). These are the items testers actually record across 26,183 tests, not reports from owners, so they describe what goes wrong at the point where it has to be fixed.
Which BMW I3 year is the most reliable?
By MOT pass rate, BMW I3 cars registered in 2021 do best at 91.0% and 2014 cars do worst at 79.4%. 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 2018, up 4.5 points on 2017.
Is the BMW I3 reliable?
Adjusted for the age and mileage of the cars tested, the BMW I3 passes 84.3% 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 BMW I3?
Start with what fails most: tyres, wiper blades and washers, 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