2025 MOT results
Mercedes-Benz C-Class common problems
The most common reason a Mercedes-Benz C-Class fails its MOT is a worn steering or suspension joint, on 16.8% of its 91,007 failed tests in 2025. Against other cars of the same age, 5 faults stand out, the widest gaps being: a worn steering or suspension joint at 16.8% of failures against 5.4% expected; corroded brake pipes at 4.2% of failures against 1.7% expected; the engine management light on at 10.9% of failures against 5.4% expected.
- Tests in 2025 358,848 Cars aged three and over
- Failed first time 25.4% 91,007 tests
- Found a dangerous defect 8.4% Unsafe to drive away
- Ended with an advisory 51.1% A problem to watch, not a failure
What fails a Mercedes-Benz C-Class MOT
Each bar is the share of failed Mercedes-Benz C-Class tests with that defect. Where we can compare it with cars of the same registration years, the marker shows what an average car of those ages records (12 of the 12 items below).
Most common reasons for failure
A test can fail for more than one defect, so shares add up to more than 100%.
| Defect | Share of failed tests |
|---|---|
| Suspension arms: ball joint excessively worn Suspension | 16.8% |
| Tyres: tread depth below requirements of 1.6mm Tyres | 12.2% |
| Malfunction indicator lamp: inoperative or indicates a malfunction Noise, emissions and leaks | 10.9% |
| Coil spring: fractured or broken Suspension | 10.7% |
| Tyres: ply or cords exposed Tyres | 6.8% |
| Tyres: cut in excess of the requirements deep enough to reach the ply or cords Tyres | 5.9% |
| Linkage ball joint dust cover no longer prevents the ingress of dirt Suspension | 5.3% |
| Parking brake efficiency below requirements Brakes | 5.2% |
| Brake pads: less than 1.5 mm thick Brakes | 4.9% |
| Rigid brake pipes: excessively corroded Brakes | 4.2% |
| Headlamp aim: too low Lamps, reflectors and electrical equipment | 4.0% |
| Washers: provides insufficient washer liquid Visibility | 3.7% |
Source:DVSA,UK Motoring analysis 2025 Updated
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Worn steering or suspension joint
16.8% of failures 5.4% expected 3.1 times as often
Play in a steering or suspension joint, where a worn ball and socket lets the wheel move where it should not.
A knock at low speed over rough ground, or vague steering, is the usual warning.
-
Tyre worn below the legal limit
12.2% of failures 8.1% expected 1.5 times as often
A tyre worn past the 1.6mm legal minimum across the middle three quarters of the tread.
A 20p coin in the main grooves: if the outer band of the coin is visible, the tyre is close to the limit.
-
Engine management light on
10.9% of failures 5.4% expected 2 times as often
The engine management light is on, or has been disconnected. Either fails the test.
A cheap code reader on the diagnostic socket will say what the car has stored before you pay for a test.
-
Broken coil spring
10.7% of failures 9.2% expected somewhat more often
A broken suspension spring, which usually snaps in the bottom coil and often fails on both sides within a year.
Look at each corner for a sagging ride height, and listen for a knock over speed bumps.
-
Tyre worn through to the cords
6.8% of failures 4.8% expected somewhat more often
The tyre is worn or damaged far enough to expose the cords underneath, which is a dangerous defect.
Run a hand round the inner and outer walls of each tyre, which is where kerbing shows.
-
Cut tyre
5.9% of failures 4.7% expected somewhat more often
A cut in the tyre deep or long enough to reach the structure underneath, usually from a kerb or debris.
Run a hand round the inner and outer walls of each tyre, which is where kerbing shows.
Which parts of the car fail
Suspension is the area that most often fails a Mercedes-Benz C-Class, on 40.8% of failed tests. That is also where it differs most from cars of the same registration years, which record 33.5%.
Failure categories
DVSA's own sections of the test. The marker is what cars of the same registration years record.
| Defect category | Share of failed tests |
|---|---|
| Suspension | 40.8% |
| Tyres | 29.7% |
| Brakes | 23.6% |
| Lamps, reflectors and electrical equipment | 23.6% |
| Noise, emissions and leaks | 14.2% |
| Visibility | 10.2% |
| Body, chassis, structure | 4.1% |
| Seat belts and supplementary restraint systems | 3.8% |
Source:DVSA,UK Motoring analysis 2025 Updated
What testers warn about
51.1% of Mercedes-Benz C-Class tests ended with at least one advisory: a fault the tester found that did not fail the test. On Mercedes-Benz C-Classes, these are the items to ask about on a car you are viewing, because they are what the last tester expected to go next.
Most common advisories
Share of all tests, passes included.
| Advisory | Share of tests |
|---|---|
| Tread depth: worn close to legal limit or worn on edge Tyres | 20.9% |
| Brake discs: worn, pitted or scored, but not seriously weakened Brakes | 8.2% |
| Rigid brake pipes: corroded, covered in grease or other material Brakes | 7.9% |
| Brake pads: wearing thin Brakes | 7.4% |
| Suspension arms: ball joint has slight play Suspension | 5.5% |
| Tyres: slightly damaged or cracking or perishing Tyres | 5.0% |
| Engine oil leak, but not excessive Noise, emissions and leaks | 4.4% |
| Suspension arms: pin or bush worn but not resulting in excessive movement Suspension | 4.1% |
| Brake discs: worn, but not excessively Brakes | 3.6% |
| Wheel bearings: slight play Suspension | 2.8% |
| Coil spring: corroded Suspension | 2.7% |
| Sub-frame: corroded but not seriously weakened Suspension | 2.2% |
Source:DVSA,UK Motoring analysis 2025 Updated
What changes as a Mercedes-Benz C-Class gets older
A 2022 Mercedes-Benz C-Class failed 11.0% of its MOT tests in 2025; a 2002 one failed 36.2%. What fails changes as much as how often, and these are the two years themselves rather than an average across them.
2022 Mercedes-Benz C-Class 11.0% failed, from 4,618 tests
- Cut tyre 29.2%
- Tyre worn through to the cords 23.7%
- Tyre worn below the legal limit 11.8%
- Bulge in a tyre 8.7%
- Worn brake pads 5.1%
- Headlamp aim set too low 3.6%
2002 Mercedes-Benz C-Class 36.2% failed, from 2,026 tests
- Broken coil spring 16.2%
- Worn steering or suspension joint 15.4%
- Engine management light on 10.4%
- Wiper blades that do not clear the screen 9.5%
- Headlamp aim out of line 8.3%
- Brake light out 8.0%
Shares are of each year's failed tests. Every MOT a particular car has had, with the defects and advisories written at each test, is on GOV.UK's MOT history service from the registration, free.
Mercedes-Benz C-Class problems: common questions
What is the most common problem with a Mercedes-Benz C-Class?
Of the faults that fail an MOT, “Suspension arms: ball joint excessively worn” is the most common: it appears on 16.8% of failed Mercedes-Benz C-Class tests. Across categories, suspension is the area that most often fails one, on 40.8% of failed tests.
How often does a Mercedes-Benz C-Class fail its MOT?
25.4% of Mercedes-Benz C-Class tests in 2025 were not passed first time, from 358,848 tests of cars aged three and over. Allowing for the age and mileage of the cars tested, that gives it a UK Motoring Reliability Score of 55 out of 100, where 50 is as expected.
Does anything fail more often on a Mercedes-Benz C-Class than on other cars?
Yes. “Suspension arms: ball joint excessively worn” appears on 16.8% of its failures against 5.4% for cars of the same age, and “Rigid brake pipes: excessively corroded” appears on 4.2% of its failures against 1.7% for cars of the same age. Where an item is missing from the national figures for a year, we use the smallest share those figures show, so the comparison never overstates the difference.
Are these the same as breakdowns or known faults?
No. These are the items a tester recorded at the MOT, which covers condition and safety: lamps, brakes, tyres, suspension, corrosion and emissions. A gearbox that is unpleasant, an infotainment screen that has died, or a car that will not start on a cold morning are not part of the test, so they are not in these figures.
Where do the figures come from?
Every normal MOT test of a Mercedes-Benz C-Class aged three and over in Great Britain in 2025, from DVSA's anonymised MOT results. Retests are excluded, and the same fault on more than one wheel counts once.
Data stories to read next
Data sources and methodology
| Figures | Source | Period | Records | Updated |
|---|---|---|---|---|
| MOT defects and advisories | Anonymised MOT tests and results Driver and Vehicle Standards Agency Derived statistics UK Motoring | 2025 | 358,848 MOT tests | 19 September 2026 |
- Shares for defects are of failed tests; shares for advisories are of all tests. A test can carry several defects, so shares add to more than 100%.
- The expected share is what an average car of the same registration years records, weighted by where this model’s failures fall. Where an item is outside the national figures for a year, the smallest share those figures show is used in its place, which is an upper bound, so the comparison never overstates a model’s problems. No expectation is published where less than 80% of the model’s failures can be compared.
- Great Britain only: DVSA does not run MOT testing in Northern Ireland. Cars under three years old are not tested.
- The descriptions of what each part does are general and the same on every model. Every figure comes from the MOT data.
Contains public sector information licensed under the Open Government Licence v3.0.