What does 4.1.4 mean on an MOT certificate?

It refers to sub-section 4.1.4 of the MOT inspection manual, "Compliance with requirements", within section 4, lamps, reflectors and electrical equipment. The letter or letters after it — (a), (b)(i) and so on — identify the specific defect from the 4 listed here. 4 Major and 0 Minor.

Which compliance with requirements defect is recorded most often?

"Product on the lens or light source which obviously reduces light intensity or changes emitted colour to other than white or yellow" (4.1.4 (b)), recorded about 0.4 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 4 · Lamps, reflectors and electrical equipment

4.1.4 Compliance with requirements

Manual indexed 3 September 2026

Quick answer

Sub-section 4.1.4 of the MOT inspection manual covers compliance with requirements and lists 4 defects. A reference like "(4.1.4 (a))" on a certificate points to the matching row below. The most recorded is "Product on the lens or light source which obviously reduces light intensity or changes emitted colour to other than white or yellow", about 0.4 times per 100 failed tests.

Official wording

The defect clauses

4.1.4 (a)Major0.1 per 100 fails
Headlamp emitted colour, position or intensity not in accordance with the requirements
Lamp of the wrong colour, position or intensity explained: what it means and what puts it right
4.1.4 (b)Major0.4 per 100 fails
Product on the lens or light source which obviously reduces light intensity or changes emitted colour to other than white or yellow
Lamp of the wrong colour, position or intensity explained: what it means and what puts it right
4.1.4 (c)Majorunder 0.1 per 100 fails
Light source and lamp not compatible
Lamp of the wrong colour, position or intensity explained: what it means and what puts it right
4.1.4 (d)Majorunder 0.1 per 100 fails
Mandatory headlamps, intended to be a matched pair, are not the same shape, size or colour

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. 3 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 4

Other sub-sections of lamps, reflectors and electrical equipment

All sections of the manual

Common questions

What does 4.1.4 mean on an MOT certificate?: It refers to sub-section 4.1.4 of the MOT inspection manual, "Compliance with requirements", within section 4, lamps, reflectors and electrical equipment. The letter or letters after it — (a), (b)(i) and so on — identify the specific defect from the 4 listed here. 4 Major and 0 Minor.
Which compliance with requirements defect is recorded most often?: "Product on the lens or light source which obviously reduces light intensity or changes emitted colour to other than white or yellow" (4.1.4 (b)), recorded about 0.4 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.