Model Reports 8 min read Updated 11 Sep 2026 DVSA open data · 7,941 tests analysed

Citroen C3 2021: reliability & common MOT faults

850 first-attempt MOT failures were recorded on the 2021 Citroen C3 in 2025. Figures are among first-attempt failed MOT tests, not among all tests.

Position lamp (rear) was the most common reason a 2021 C3 failed its MOT — 14.5% of its failed first attempts.

First-attempt pass

89.3%

of 7,941 first tests (2025)

First tests

7,941

test year 2025

Failed first attempts

850

failed first-attempt tests

MOT pass rates

First-attempt and official-style rates among class 4 first tests of the year.

First-attempt pass

89.3%

of 7,941 first tests (2025)

Official-style pass

92.2%

incl. same-day PRS fixes

First tests

7,941

class 4 · first MOT of the year

Typical age 4.0 yrs · median mileage 26,438 mi

vs 2024: -1.3 pp first-attempt

Note:

  • Class 4 cars · first MOT of the year per vehicle · P/PRS/F outcomes (2025 data).
  • PRS (fixed at the station the same day) counts as a fail in the first-attempt rate.
  • Raw outcomes for this cohort — not adjusted for age, mileage, or peer mix.
  • MOT doesn't test engine or gearbox internals.

Common faults

Failure patterns that show up more often on this registration year than on similar cars.

These MOT failure patterns show up more often on this registration year than on similar cars of the same class, age, and mileage.

Shares below are measured across the 850 failed first attempts in 2025 that the age-and-mileage comparison can be computed on.

Standout: Position lamp (rear) — 14.5% of this year's failed first attempts

Recorded on 123 of those tests. It tops the table on elevation — about 29× more often than on similar cars of the same age and mileage. On this year it is also the commonest failure, so it answers both questions at once. The full ranked list is in the table below.

Fault pattern Location Failures vs similar cars Share of fails Confidence
Position lamp (rear)
Lamps, reflectors and electrical equipment > Position lamps > Position lamp
 Rear 123 ×29 14.5% Strong
Front fog lamps (front)
Lamps, reflectors and electrical equipment > Front and rear fog lamps > Front fog lamps > Front fog lamps
 Front 22 ×9.0 2.6% Possible
Drive shafts — Joints (front)
Body, chassis, structure > Transmission > Drive shafts > Joints
 Front 41 ×6.3 4.8% Likely
Side repeaters
Lamps, reflectors and electrical equipment > Direction indicators > Flashing type > Side repeaters
 Any 23 ×4.3 2.7% Possible

Only patterns that clear minimum sample and elevation thresholds are shown (at least 20 failures and about 2.0× more often than similar cars).

Note: Rates and comparisons are among first-attempt failed tests, not all MOTs. Patterns come from MOT defect codes — not manufacturer service bulletins, recalls, or a diagnosis of any individual car. Failures and advisories are listed separately.

Wear patterns

Usage and mileage effects that often track road use rather than model design.

These patterns look like wear or usage effects rather than model-specific design faults. Tyres, brake friction material, and alignment-related defects often track mileage and road use.

Pattern Location Failures vs similar cars Share of fails Confidence
Brake discs (front)
Brakes > Mechanical brake components > Brake discs and drums > Brake discs
 Front 69 ×7.8 8.1% Wear
Brake pads (front)
Brakes > Mechanical brake components > Brake linings and pads > Brake pads
 Front 82 ×2.0 9.6% Wear
Note: These patterns are not treated as a model design fault in our common-faults ranking.

Advisories

Notes recorded at the test that appear more often than on similar cars.

Advisory notes recorded on failed first-attempt tests that appear more often than on similar cars.

Advisory pattern Location Notes vs similar cars Share Confidence
Pins and bushes (front)
Suspension > Suspension arms > Pins and bushes
 Front 45 ×3.9 5.3% Elevated
Brake discs (front)
Brakes > Mechanical brake components > Brake discs and drums > Brake discs
 Front 194 ×2.7 22.8% Wear
Note: Advisories are not a fail rate — they flag issues noted at the test, often before they become failures.

If you are buying one

What this year's MOT record means for the decision in front of you.

Nothing separates this year from the C3 either side of it, so buy on the individual car. The checks below are the items that actually failed 2021 C3, commonest first.

Other C3 years worth knowing about

Newer cars always pass more often, so a plain "best year" list would just rank by age. These are the years that beat or miss the trend their own neighbouring years set — the only age-adjusted signal this data supports.

Year vs the years either side First-attempt pass (rises with newer cars) First tests
2020 C3 +1.4 pp better 86.6% 7,568

What to check on a 2021 C3

The items that failed 2021 C3 most often, as a share of the year's failed first attempts. This is what goes wrong, not what is unusual — the table further up the page covers that.

  • Position lamp (rear) — recorded on 14.5% of failed first attempts
  • Tyres — Condition (front) — recorded on 10.4% of failed first attempts
  • Brake pads (front) — recorded on 9.6% of failed first attempts
  • Headlamp aim — recorded on 8.2% of failed first attempts
  • Brake discs (front) — recorded on 8.1% of failed first attempts

Every figure here is a first-attempt MOT rate from DVSA open data for this model line. MOTs do not test engine or gearbox internals, so this is a pre-purchase checklist, not a full reliability score.

FAQs

Short answers about how to read this model-year guide.

Position lamp (rear) was the most common reason a 2021 C3 failed its MOT — 14.5% of its failed first attempts. In 2025, 89.3% of 7,941 first MOTs on the 2021 Citroen C3 passed first time (PRS — items fixed at the station the same day — counted as a fail). The official-style rate including PRS is 92.2%. Among 850 failed first-attempt MOT tests (test year 2025), Position lamp (rear) appears more often than on similar…
Ranked by how often they were actually recorded, the items that failed 2021 Citroen C3s most often at the first attempt were Position lamp (rear) (14.5%), Tyres — Condition (front) (10.4%) and Brake pads (front) (9.6%) — each as a share of the year's failed first attempts. That is what goes wrong on the car. It is a different question from which patterns are unusual for the class, which the common-faults table answe…
Among failed first-attempt tests we highlight patterns that appear more often than on similar cars. Top example: Position lamp (rear) (14.5% of those tests; 123 observed failures; about 29× more often than similar cars). These are statistical signals, not a diagnosis of any individual car.
Position lamp (rear) shows up more often than on similar cars (14.5% of those tests; 123 observed failures; about 29× more often than similar cars). That does not prove a design fault — age, mileage, and how the car was used still matter. Treat it as a pre-purchase check point, not a manufacturer service bulletin.
Common MOT problem areas for the 2021 Citroen C3 include Position lamp (rear), Front fog lamps (front), Drive shafts — Joints (front). These patterns show up more often than on similar cars after we filter out sparse noise — not a full list of every possible fault on an individual car.
Advisories flag issues noted at the test and are not a fail rate. We show advisory patterns that appear more often than on similar cars among failed first-attempt tests, separate from common failure rows. Use them as early-warning checks, not as a pass/fail score.
This page highlights MOT failure patterns for the 2021 Citroen C3 (registration year) using UK DVSA open data for the selected test year. Patterns are compared with cars of a similar age and mileage. It is a buyer checklist from MOT defect statistics — not a full service history or manufacturer service-bulletin list.
No. MOT tests do not cover engine internals, gearboxes, or many electronic modules. Patterns here come from MOT defect statistics only and should not be read as engine or gearbox reliability scores.

About this data

How this page is built and what it can (and can't) say.

These figures come from UK MOT open data for this model year. We surface common failure patterns against similar cars — not a full reliability score, and not a pass/fail verdict on any individual vehicle.

2024 2025

What we include

UK Class 4 cars only. Normal MOT tests (not retests); first test per vehicle per calendar year; results pass, PRS, or fail.

Same-day repairs

PRS means the car failed items that were fixed at the test station and then passed the same day. We count PRS as a first-attempt fail in headline rates so same-day repairs do not hide problems.

How we compare

We compare this model year with other Class 4 cars of similar age and mileage in the same test year. This model family is left out of the peer group so the car is not measured against itself.

What this does not cover

  • MOTs do not cover engine internals, gearboxes, or many electronics — this is not a full reliability score.
  • Common faults come from MOT defect stats, not manufacturer TSBs or recalls.
  • Age and mileage matching reduces — but does not remove — differences in how cars were used and maintained.
  • We never invent pass rates, star scores, or ranks when those data marts are missing.

Contains public sector information licensed under the Open Government Licence v3.0.

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