What does 5.3.5 mean on an MOT certificate?

It refers to sub-section 5.3.5 of the MOT inspection manual, "Gas, air and fluid suspension", within section 5, axles, wheels, tyres and suspension. The letter or letters after it — (a), (b)(i) and so on — identify the specific defect from the 4 listed here. 2 of them are graded Dangerous, 2 Major and 0 Minor.

Which gas, air and fluid suspension defect is recorded most often?

"An obvious leak from any part of the system" (5.3.5 (c)), recorded about 0.0 times per 100 failed MOT tests nationally.

Does a Minor defect fail the MOT?

No. a defect with no significant effect on safety or the environment. Recorded on the certificate; the vehicle passes. Major and Dangerous defects fail. A Dangerous defect also means the car must not be driven until it is repaired.

Section 5 · Axles, wheels, tyres and suspension

5.3.5 Gas, air and fluid suspension

Manual indexed 3 September 2026

Quick answer

Sub-section 5.3.5 of the MOT inspection manual covers gas, air and fluid suspension and lists 4 defects, 2 of them Dangerous. A reference like "(5.3.5 (a))" on a certificate points to the matching row below. The most recorded is "An obvious leak from any part of the system", about 0.0 times per 100 failed tests.

Official wording

The defect clauses

5.3.5 (a)Dangerousunder 0.1 per 100 fails
A gas, air or fluid suspension system inoperative
5.3.5 (b)(i)Majorunder 0.1 per 100 fails
A gas, air or fluid suspension system component damaged, modified or deteriorated in a way that it would adversely affect the functioning of the system
5.3.5 (b)(ii)Dangerousunder 0.1 per 100 fails
A gas, air or fluid suspension system component damaged, modified or deteriorated in a way that its function is seriously affected
5.3.5 (c)Majorunder 0.1 per 100 fails
An obvious leak from any part of the system

Wording and categories reproduced from the DVSA inspection manual under the Open Government Licence. Frequencies are items per 100 failed class 4 tests across the DVSA anonymised MOT dataset; a clause with no figure was not recorded often enough to appear in any model’s top forty failure items. 0 of 4 clauses link to our own explanation.

Grading

What the categories mean

Dangerous: a direct and immediate risk to road safety or the environment. The vehicle fails and must not be driven until repaired, even to a garage.
Major: a defect that affects safety, the environment or other road users. The vehicle fails.
Minor: a defect with no significant effect on safety or the environment. Recorded on the certificate; the vehicle passes.

The full guide to defect grading

Section 5

Other sub-sections of axles, wheels, tyres and suspension

5.1.1Axles
5.1.2Stub axles
5.1.3Wheel bearings
5.2.1Road wheel and hub
5.2.2Road wheel condition
5.2.3Tyres
5.3.1Springs
5.3.2Shock absorbers
5.3.3Suspension arms, rods, struts, sub-frames, anti-roll bars etc.
5.3.4Suspension joints, pins and bushes
5.3.6Complete suspension system

All sections of the manual

Common questions

What does 5.3.5 mean on an MOT certificate?: It refers to sub-section 5.3.5 of the MOT inspection manual, "Gas, air and fluid suspension", within section 5, axles, wheels, tyres and suspension. The letter or letters after it — (a), (b)(i) and so on — identify the specific defect from the 4 listed here. 2 of them are graded Dangerous, 2 Major and 0 Minor.
Which gas, air and fluid suspension defect is recorded most often?: "An obvious leak from any part of the system" (5.3.5 (c)), recorded about 0.0 times per 100 failed MOT tests nationally.
Does a Minor defect fail the MOT?: No. a defect with no significant effect on safety or the environment. Recorded on the certificate; the vehicle passes. Major and Dangerous defects fail. A Dangerous defect also means the car must not be driven until it is repaired.