What does 4.13 mean on an MOT certificate?

It refers to sub-section 4.13 of the MOT inspection manual, "Battery(ies)", 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 3 listed here. 2 Major and 1 Minor.

Which battery(ies) defect is recorded most often?

"A battery insecure and likely to fall from carrier or cause a short circuit" (4.13 (a)(ii)), 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 4 · Lamps, reflectors and electrical equipment

4.13 Battery(ies)

Manual indexed 3 September 2026

Quick answer

Sub-section 4.13 of the MOT inspection manual covers battery(ies) and lists 3 defects. A reference like "(4.13 (a)(i))" on a certificate points to the matching row below. The most recorded is "A battery insecure and likely to fall from carrier or cause a short circuit", about 0.0 times per 100 failed tests.

Official wording

The defect clauses

4.13 (a)(i)Minor
A battery insecure but not likely to fall from carrier
4.13 (a)(ii)Majorunder 0.1 per 100 fails
A battery insecure and likely to fall from carrier or cause a short circuit
4.13 (b)Major
A battery leaking

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 3 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 4.13 mean on an MOT certificate?: It refers to sub-section 4.13 of the MOT inspection manual, "Battery(ies)", 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 3 listed here. 2 Major and 1 Minor.
Which battery(ies) defect is recorded most often?: "A battery insecure and likely to fall from carrier or cause a short circuit" (4.13 (a)(ii)), 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.