Model Reports 4 min read Updated 18 Oct 2026

Citroen C4 2021: reliability & common MOT faults

In 2025, 79 in every 100 first MOTs on a 2021 Citroen C4 were passes. Most common reason for a fail: Anti-roll bar linkage ball joint dust cover (front).

Summary

At the same mileage, a diesel 2021 Citroen C4 passed first time more often than an electric one: 84 in every 100 against 76 in every 100.

At a glance

How 6,040 first tests went in 2025.

Passed first time
79 in every 100
Did not pass first time
21 in every 1001,246 failed first-attempt tests
The typical car
4 yearsabout 30,012 miles
First tests counted
6,040

What failed most often

  1. Anti-roll bar linkage ball joint dust cover (front)17 in every 100 failed tests
  2. Windscreen wipers (front)15 in every 100 failed tests
  3. Tyre condition (front)9 in every 100 failed tests

How we count this. Data: UK MOT open data, 2025. Only Class 4 cars on their first MOT of the year are counted. A car that fails and is fixed at the test station still counts as a fail in the first-attempt rate. These are raw results, not adjusted for age, mileage, or peer mix. The MOT does not test engine or gearbox internals.

Note:

These are patterns across 2021 Citroen C4 vehicles in 2025, not a prediction that any one car will have them. Faults are grouped by part of the car. A wear pattern follows age and use more than the way the car was built. They come from MOT defect codes, not manufacturer bulletins, recalls or a diagnosis of any one car.

Suspension

Three faults. The strongest is the anti-roll bar linkage ball joint dust cover (front): 31 times as often as on similar cars.

Figures below are measured across the 1,246 failed first attempts in 2025 that had a mileage recorded, which allows a like-for-like comparison.

We only list faults with at least 20 failures and a rate of about 2.0 times that of similar cars, which keeps one-off results out of the list.

Anti-roll bar linkage ball joint dust cover (front)

Failed on 210 first tests31 times as often as similar carsStrong evidence

What it means

A suspension joint dust cover that is severely deteriorated is Minor. It becomes Major once it is missing or no longer prevents the ingress of dirt, so what matters is whether it still keeps dirt out. DVSA words this for any suspension joint dust cover, and files it here under anti-roll bars.

Anti-roll bar ball joint dust cover (front)

Failed on 78 first tests29 times as often as similar carsLikely evidence

What it means

A missing anti-roll bar ball joint dust cover is Major, and so is one that no longer prevents the ingress of dirt. A cover that is only severely deteriorated is Minor. DVSA uses one wording for the dust cover on any suspension joint.

Suspension arm ball joint (front)

Failed on 97 first tests8.4 times as often as similar carsLikely evidence

What it means

A suspension arm ball joint is failed under the general suspension pin, bush or joint wording. Excessively worn is Major, and likely to become detached is graded Dangerous.

Also noted as an advisory

Testers also noted it as an advisory, worn but not yet failing, on 93 first tests, 12 times as often as on similar cars.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage. Advisories count notes recorded on failed first tests only.

Visibility

One fault: windscreen washers (front), 3.3 times as often as on similar cars.

Windscreen washers (front)

Failed on 109 first tests3.3 times as often as similar carsLikely evidence

What it means

Windscreen washers that are not working, or do not provide sufficient fluid to clear the windscreen, are graded Major. They must provide enough fluid for the wipers to clear the windscreen effectively. Vehicles with an opening windscreen, or some other adequate view to the front, left and right, are not inspected for washers.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Brakes

One fault and one wear pattern. The strongest is the brake discs (rear): 2.9 times as often as on similar cars.

Brake discs (rear)

Failed on 53 first tests2.9 times as often as similar carsWear pattern

What it means

A brake disc or drum must be significantly worn before it is rejected, and being worn below the manufacturer's recommended limits is not a reason in itself. Significantly and obviously worn is Major, as is contamination with oil or grease. A disc or drum that is fractured, insecure, seriously weakened or missing is graded Dangerous.

Also noted as an advisory

Testers also noted it as an advisory, worn but not yet failing, on 218 first tests, 2.5 times as often as on similar cars.

Brake performance (roller test, rear)

Failed on 31 first tests2.6 times as often as similar carsPossible evidence

What it means

A wheel with no recorded braking effort on the roller test is graded Dangerous. Inadequate effort, a brake grabbing severely, abnormal lag and excessive fluctuation in effort are each Major. So is significant brake effort recorded with no brake applied, which indicates a binding brake.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage. Advisories count notes recorded on failed first tests only.

MOT pass rates

How first tests ended, and how the pass rates are counted.

Passed first time
79in every 100
Passed on the first test.
Fixed at the station
4in every 100
Failed, then fixed at the test station the same day.
Failed
17in every 100
Did not pass, and were not fixed at the test station.

First-attempt pass 79.4% of 6,040 first tests (2025): only cars that passed first time count. Official-style pass 82.9%: cars fixed at the test station also count as a pass. The 4 fixed and the 17 not fixed make the 21 in every 100 that did not pass first time.

By fuel type

First testsTypical mileagePassed first time, as testedPassed first time, same mileage
Petrol3,99629,800 miles7979
Electric1,21828,284 miles7776
Diesel82634,018 miles8384

Figures are in every 100 first tests. Cars with more miles usually fail more often, so the same-mileage figure gives every fuel the mileage mix of all the cars in this year.

Same model, other years

Passed first time in every 100, all tested in 2025.

4060801002005201020152021Older cars
40608010020102021Older cars

Newer cars are younger, so look for a jump rather than the climb. A year earlier (2024), when these cars were a year younger, 82 in every 100 passed first time.

YearPassed first timeFirst tests
200554 in every 100617
200650 in every 1001,235
200749 in every 1003,668
200846 in every 1004,812
200948 in every 1003,669
201046 in every 1004,635
201153 in every 1005,770
201254 in every 1007,285
201354 in every 10010,925
201456 in every 10018,913
201560 in every 10025,465
201662 in every 10015,965
201767 in every 100836
201873 in every 1002,576
201977 in every 1004,766
202084 in every 1001,641
2021 This car79 in every 1006,040
202283 in every 1007,742

If you are buying one

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

Mileage matters most on a 2021 Citroen C4.

Of 2021 Citroen C4 vehicles with under 19,000 miles, 88 in every 100 passed their 2025 MOT first time. With 44,000 miles or more, 71 in every 100 did.

Under 19,0001,203 tests
88
19,000–26,0001,152 tests
81
26,000–34,000 Typical car1,257 tests
80
34,000–44,0001,184 tests
77
44,000 and over1,244 tests
71

Which fuel?

Typical mileagePassed first time,
as tested		Passed first time,
same mileage
Petrol29,800 miles7979
Electric28,284 miles7776

Figures are in every 100 first tests. At the same mileage there is no clear difference between the two.

What to check at your mileage

How often each fault turned up on a failed first test, by the car's mileage. Read it as: what is likely to need looking at on a car like the one in front of you.

Under 19,00026,000–34,00044,000 and over
Anti-roll bar linkage ball joint dust cover (front)1.53.05.2
Windscreen wipers (front)2.33.62.9
Tyre condition (front)1.22.02.2
Windscreen washers (front)0.91.23.7
Suspension arm ball joint (front)0.61.33.2

Faults per 100 first tests, by the car's mileage at the test.

When a car fails

50in every 100

of failed cars had one item to fix.

21in every 100

of failed cars had three or more items to fix.

4in every 100

of all first tests had a defect the tester marked dangerous (unsafe to drive away).

Every figure here is a first-attempt MOT rate from DVSA open data for this model line, for cars of this model year tested in 2025. Each mileage band holds a fifth of the tests. 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.

At the same mileage, a diesel 2021 Citroen C4 passed first time more often than an electric one: 84 in every 100 against 76 in every 100. In 2025, 79.4% of 6,040 first MOTs on the 2021 Citroen C4 passed first time (PRS: items fixed at the station the same day, counted as a fail). The official-style rate including PRS is 82.9%. Among 1,246 failed first-attempt MOT tests (test year 2025), Anti-roll bar linkage ball joint dust cover (front) appears more often than on similar cars (16.9% of those tests; 210 observed failures; about 31× more often than similar cars). There is no single reliability score here; this is a pre-purchase checklist built from DVSA open data, not a guarantee for any individual car.
Ranked by how often they were actually recorded, the items that most often failed a 2021 Citroen C4 at the first attempt were Anti-roll bar linkage ball joint dust cover (front) (16.9%), Windscreen wipers (front) (14.9%) and Tyre condition (front) (9.1%), each as a share of the year's failed first attempts. That is what goes wrong most often on the car. The common faults table shows a different measure: faults that are unusual compared with similar cars.
Among failed first-attempt tests we highlight patterns that appear more often than on similar cars. Top example: Anti-roll bar linkage ball joint dust cover (front) (16.9% of those tests; 210 observed failures; about 31× more often than similar cars). These are statistical signals, not a diagnosis of any individual car.
Anti-roll bar linkage ball joint dust cover (front) shows up more often than on similar cars (16.9% of those tests; 210 observed failures; about 31× 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 checkpoint, not a manufacturer service bulletin.
Common MOT problem areas for the 2021 Citroen C4 include Anti-roll bar linkage ball joint dust cover (front), Anti-roll bar ball joint dust cover (front), Suspension arm ball joint (front). These are the faults that stand out compared with similar cars, not a complete list of what can go wrong on any individual car.
This page highlights MOT failure patterns for the 2021 Citroen C4 (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.
  • If the data for a car is too thin to say anything useful, we say so rather than guess.

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

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