What does 5.3.3 mean on an MOT certificate?

It refers to sub-section 5.3.3 of the MOT inspection manual, "Suspension arms, rods, struts, sub-frames, anti-roll bars etc.", 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 6 listed here. 3 of them are graded Dangerous, 3 Major and 0 Minor.

Which suspension arms, rods, struts, sub-frames, anti-roll bars etc. defect is recorded most often?

"A suspension component excessively damaged or corroded" (5.3.3 (b)(i)), recorded about 0.7 times per 100 failed MOT tests nationally. We explain what it means and what puts it right.

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

5.3.3 Suspension arms, rods, struts, sub-frames, anti-roll bars etc.

Manual indexed 3 September 2026

Quick answer

Sub-section 5.3.3 of the MOT inspection manual covers suspension arms, rods, struts, sub-frames, anti-roll bars etc. and lists 6 defects, 3 of them Dangerous. A reference like "(5.3.3 (a)(i))" on a certificate points to the matching row below. The most recorded is "A suspension component excessively damaged or corroded", about 0.7 times per 100 failed tests.

Official wording

The defect clauses

5.3.3 (a)(i)Majorunder 0.1 per 100 fails
A suspension component insecurely attached to chassis or axle
Suspension mounting corroded or insecure explained: what it means and what puts it right
5.3.3 (a)(ii)Dangerousunder 0.1 per 100 fails
A suspension component missing, likely to become detached or directional stability impaired
Suspension mounting corroded or insecure explained: what it means and what puts it right
5.3.3 (b)(i)Major0.7 per 100 fails
A suspension component excessively damaged or corroded
Suspension mounting corroded or insecure explained: what it means and what puts it right
5.3.3 (b)(ii)Dangerous0.1 per 100 fails
A suspension component fractured or likely to fail
Suspension mounting corroded or insecure explained: what it means and what puts it right
5.3.3 (c)(i)Majorunder 0.1 per 100 fails
A suspension component with an unsafe modification
5.3.3 (c)(ii)Dangerous
A suspension component modified so that the suspension is inoperative or likely to foul other components

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. 4 of 6 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

All sections of the manual

Common questions

What does 5.3.3 mean on an MOT certificate?: It refers to sub-section 5.3.3 of the MOT inspection manual, "Suspension arms, rods, struts, sub-frames, anti-roll bars etc.", 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 6 listed here. 3 of them are graded Dangerous, 3 Major and 0 Minor.
Which suspension arms, rods, struts, sub-frames, anti-roll bars etc. defect is recorded most often?: "A suspension component excessively damaged or corroded" (5.3.3 (b)(i)), recorded about 0.7 times per 100 failed MOT tests nationally. We explain what it means and what puts it right.
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.