The MOT Files

Known faults, from the test record

Citroen C1 common problems

What fails on the Citroen C1 at MOT, which parts are behind it, and how each model year compares. From 162,679 DVSA test records.

Data updated

Quick answer

The Citroen C1's most common MOT problems are tyres, bulbs and lamps, brake callipers, recorded in 29.6%, 25.1% and 17.6% of failed tests respectively. By model year, 2021 cars pass most often (89.9%) and 2006 cars least (51.7%), 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 Citroen C1 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 162,679 cars.

By component

What wears out on a C1

Failure items grouped by the part behind them, with the share of failed Citroen C1 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

    29.6% 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” — explained12.5%
    • “A tyre cords visible or damaged” — explained6.2%
    • “A tyre seriously damaged” — explained5.9%
    • “A tyre seriously damaged” — explained5.0%

    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

    25.1% 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” — explained11.0%
    • “Stop lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning” — explained4.3%
    • “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” — explained3.6%
    • “A headlamp or light source missing, inoperative or more than ½ not functioning in the case of LED” — explained3.2%

    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.Brake callipers

    17.6% of failed tests

    Pistons and slider pins seize with corrosion and disuse, dragging a brake on or leaving one side weak; shows as imbalance on the roller tester.

    • “Significant brake effort recorded with no brake applied indicating a binding brake” — explained12.5%
    • “Significant brake effort recorded with no brake applied indicating a binding brake” — explained2.8%
    • “Brakes imbalance across an axle such that the braking effort from any wheel is less than 70% of the maximum effort recorded from the other wheel on the same axle.” — explained2.3%

  4. 4.Suspension bushes

    14.6% 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” — explained6.6%
    • “A suspension pin, bush or joint excessively worn” — explained5.9%
    • “A suspension joint dust cover missing or no longer prevents the ingress of dirt etc” — explained2.1%

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

  5. 5.Suspension arms and mountings

    12.0% 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” — explained10.2%
    • “A suspension component excessively damaged or corroded” — explained1.8%

  6. 6.Headlamp aim

    12.0% 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” — explained9.1%
    • “The aim of a headlamp is not within limits laid down in the requirements” — explained2.8%

  7. 7.Exhaust system

    11.1% of failed tests

    Silencers and pipes rust through from the inside on short-trip cars; rubber hangers perish.

    • “Exhaust system leaking or insecure” — explained6.7%
    • “Exhaust system leaking or insecure” — explained2.5%
    • “An induction or exhaust leak that could affect emissions levels” — explained1.9%

    Across all cars, exhaust system failures climb 104-fold between three and fifteen years, peaking at 15+ years. How long exhaust system last

  8. 8.Brake pipes

    10.7% 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” — explained10.7%

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

By registration year

C1 problems by year

MOT pass rate for Citroen C1 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 5.3 points, is larger than wear explains and most likely marks a change in the cars themselves.

200652%
200753%+1.7
200853%−0.7
200955%+2.8
201059%+3.4
201161%+1.7
201265%+4.0
201368%+3.2
201473%+5.3
201576%+2.5
201676%+0.8
201780%+3.7
201884%+4.1
201984%+0.1
202086%+2.2
202190%+3.4

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 C1 owners about

Advisories are the same parts a year or two earlier. Share of all Citroen C1 tests carrying an advisory for each.

Go deeper

The rest of the C1 file

Common questions

What are the most common problems with a Citroen C1?
Going by what fails the MOT, tyres (recorded in 29.6% of failed tests), bulbs and lamps (recorded in 25.1% of failed tests), and brake callipers (recorded in 17.6% of failed tests). These are the items testers actually record across 162,679 tests, not reports from owners, so they describe what goes wrong at the point where it has to be fixed.
Which Citroen C1 year is the most reliable?
By MOT pass rate, Citroen C1 cars registered in 2021 do best at 89.9% and 2006 cars do worst at 51.7%. 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 5.3 points on 2013.
Is the Citroen C1 reliable?
Adjusted for the age and mileage of the cars tested, the Citroen C1 passes 68.7% 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 Citroen C1?
Start with what fails most: tyres, bulbs and lamps, 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