2025 MOT results
Porsche Cayman common problems
The most common reason a Porsche Cayman fails its MOT is a sidelight out, on 11.8% of its 1,634 failed tests in 2025. Against other cars of the same age, 3 faults stand out: emissions above the limit at 8.5% of failures against 2.5% expected; corroded brake pipes at 6.5% of failures against 2.2% expected; headlamp aim set too high at 6.1% of failures against 2.8% expected.
- Tests in 2025 14,704 Cars aged three and over
- Failed first time 11.1% 1,634 tests
- Found a dangerous defect 2.7% Unsafe to drive away
- Ended with an advisory 30.0% A problem to watch, not a failure
What fails a Porsche Cayman MOT
Each bar is the share of failed Porsche Cayman 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 (11 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 |
|---|---|
| Position lamp: not working Lamps, reflectors and electrical equipment | 11.8% |
| Tyres: tread depth below requirements of 1.6mm Tyres | 10.7% |
| Catalyst emissions: lambda reading after 2nd fast idle outside specified limits Noise, emissions and leaks | 8.5% |
| Coil spring: fractured or broken Suspension | 7.7% |
| Rigid brake pipes: excessively corroded Brakes | 6.5% |
| Wipers: does not clear the windscreen effectively Visibility | 6.2% |
| Headlamp aim: too high Lamps, reflectors and electrical equipment | 6.1% |
| Tyres: cut in excess of the requirements deep enough to reach the ply or cords Tyres | 5.5% |
| Suspension arms: ball joint excessively worn Suspension | 4.3% |
| Parking brake efficiency below requirements Brakes | 3.9% |
| Malfunction indicator lamp: inoperative or indicates a malfunction Noise, emissions and leaks | 3.8% |
| Tyres: bulge, caused by separation or partial failure of its structure Tyres | 3.4% |
Source:DVSA,UK Motoring analysis 2025 Updated
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Sidelight out
11.8% of failures 10.2% expected somewhat more often
A sidelight, also called a position lamp, not working. It marks the width of the car at night.
Walk round the car with the lights on and the hazards going; these are the cheapest failures to avoid.
-
Tyre worn below the legal limit
10.7% of failures 7.8% expected somewhat more 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.
-
Emissions above the limit
8.5% of failures 2.5% expected 3.4 times as often
The exhaust gases are outside the limits for the car, which can be the catalytic converter, a sensor, or simply a poor state of tune.
A long run before the test helps a catalyst get hot; a persistent failure usually needs a diagnosis.
-
Broken coil spring
7.7% of failures 8.9% expected about as expected
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.
-
Corroded brake pipes
6.5% of failures 2.2% expected 3 times as often
Corroded or damaged brake pipework. It is a safety item, and on older cars the rear pipes go first.
Look along the pipes under the sills with a torch; flaking rust rather than surface staining is the problem.
-
Wiper blades that do not clear the screen
6.2% of failures 6.3% expected about as expected
Wiper blades that leave the windscreen smeared or streaked across the area the driver looks through.
Look for split or hardened rubber, and lift each blade to see whether it still sits flat.
Which parts of the car fail
Lamps, reflectors and electrical equipment is the area that most often fails a Porsche Cayman, on 32.1% of failed tests. The widest gap against cars of the same registration years is tyres, on 24.8% against 21.4% expected.
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 |
|---|---|
| Lamps, reflectors and electrical equipment | 32.1% |
| Tyres | 24.8% |
| Brakes | 20.3% |
| Suspension | 18.2% |
| Noise, emissions and leaks | 15.4% |
| Visibility | 13.0% |
| Body, chassis, structure | 4.2% |
| Identification of the vehicle | 4.2% |
Source:DVSA,UK Motoring analysis 2025 Updated
What testers warn about
30.0% of Porsche Cayman tests ended with at least one advisory: a fault the tester found that did not fail the test. On Porsche Caymans, 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 | 8.8% |
| Brake discs: worn, pitted or scored, but not seriously weakened Brakes | 6.6% |
| Rigid brake pipes: corroded, covered in grease or other material Brakes | 6.3% |
| Tyres: slightly damaged or cracking or perishing Tyres | 6.0% |
| Engine oil leak, but not excessive Noise, emissions and leaks | 2.0% |
| Nail in tyre Non-component advisories | 1.8% |
| Play in steering rack inner joint(s) Non-component advisories | 1.7% |
| Brake pads: wearing thin Brakes | 1.6% |
| Suspension arms: ball joint has slight play Suspension | 1.5% |
| Suspension arms: pin or bush worn but not resulting in excessive movement Suspension | 1.4% |
| Tyres: cut but not deep enough to reach the ply or cords Tyres | 1.1% |
| Brake discs: worn, but not excessively Brakes | 1.1% |
Source:DVSA,UK Motoring analysis 2025 Updated
Porsche Cayman problems: common questions
What is the most common problem with a Porsche Cayman?
Of the faults that fail an MOT, “Position lamp: not working” is the most common: it appears on 11.8% of failed Porsche Cayman tests. Across categories, lamps, reflectors and electrical equipment is the area that most often fails one, on 32.1% of failed tests.
How often does a Porsche Cayman fail its MOT?
11.1% of Porsche Cayman tests in 2025 were not passed first time, from 14,704 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 79 out of 100, where 50 is as expected.
Does anything fail more often on a Porsche Cayman than on other cars?
Yes. “Catalyst emissions: lambda reading after 2nd fast idle outside specified limits” appears on 8.5% of its failures against 2.5% for cars of the same age, and “Rigid brake pipes: excessively corroded” appears on 6.5% of its failures against 2.2% 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 Porsche Cayman 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 | 14,704 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.