73 Auto Research · MOT statistics

The most common reasons cars fail the MOT

The most common MOT failure in Great Britain in 2023–24 was “Position lamp: not working”, on 2.6% of 65,477,892 DVSA tests, followed by “Tread depth: tread depth below requirements of 1.6mm” (2.4%) and “Coil spring: fractured or broken” (2.3%). 24.0% of failed tests failed only on lights or the driver's view of the road.

Source: DVSA anonymised MOT data, 2023-01-01 to 2024-12-30 (n = 65,477,892 tests). Download the data (CSV)

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Data to 2024-12-30 · Page updated 2026-09-28 · Publisher: 73 Auto

Key findings

DVSA dataThe most common reason for failing an MOT in 2023–24 was “Position lamp: not working”, found on 2.6% of all tests (1,684,901 tests, DVSA data).
DVSA dataThe next most common MOT failures were “Tread depth: tread depth below requirements of 1.6mm” (2.4% of tests) and “Coil spring: fractured or broken” (2.3%), DVSA data 2023–24.
DVSA data24.0% of failed MOTs failed only on lights and the driver's view of the road (bulbs, wipers, washers, mirrors and the windscreen) — 4,469,792 tests in 2023–24.
DVSA data16.1% of failed MOTs failed on lights and electrics alone (3,007,761 tests, DVSA data 2023–24).
DVSA dataLights, reflectors and electrical was the most common failure area, on 39.1% of failed tests, followed by suspension (31.2%) and brakes (23.8%).

At a glance

The most common reasons cars fail the MOT: headline figures
Figure	Value	Basis	Type
Tests analysed	65,477,892	2023–24	DVSA data
Tests with a fail-level defect	18,656,275	of 18,656,905 failed or PRS tests	DVSA data
Failed on lights or view only	24.0%	4,469,792 tests	DVSA data
Average fail-level defects per failed test	2.1	18,656,275 tests	DVSA data

Official data

Counts and rates taken directly from DVSA's MOT records: 73 Auto counted them, but applied no model or adjustment.

The 30 most common MOT failures

DVSA data

The 30 most common MOT fail items, 2023–24
Defect (DVSA wording)	Rank	Area	Category	Tests	Share of all tests	Share of failed tests
Position lamp: not working	1	Lights, reflectors and electrical	Major	1,684,901	2.57%	9.0%
Tread depth: tread depth below requirements of 1.6mm	2	Tyres	Dangerous	1,598,898	2.44%	8.6%
Coil spring: fractured or broken	3	Suspension	Major	1,520,007	2.32%	8.1%
Wipers: does not clear the windscreen effectively	4	Driver's view of the road	Major	1,383,455	2.11%	7.4%
Stop lamp: not working	5	Lights, reflectors and electrical	Major	1,282,860	1.96%	6.9%
Brake pads: less than 1.5 mm thick	6	Brakes	Dangerous	1,239,514	1.89%	6.6%
Washers: provides insufficient washer liquid	7	Driver's view of the road	Major	952,375	1.45%	5.1%
Headlamp: not working on dipped beam	8	Lights, reflectors and electrical	Major	952,093	1.45%	5.1%
Ball joint: ball joint excessively worn	9	Suspension	Major	934,284	1.43%	5.0%
Joints: constant velocity boot split or insecure, no longer prevents the ingress of dirt	10	Body, chassis and structure	Major	892,068	1.36%	4.8%
Condition: has ply or cords exposed	11	Tyres	Dangerous	888,583	1.36%	4.8%
Headlamp aim: projected beam image is obviously incorrect	12	Lights, reflectors and electrical	Major	857,651	1.31%	4.6%
Condition: has a cut in excess of the requirements deep enough to reach the ply or cords	13	Tyres	Major	854,364	1.31%	4.6%
Pins and bushes: pin or bush excessively worn	14	Suspension	Major	786,424	1.20%	4.2%
Headlamp aim: too low	15	Lights, reflectors and electrical	Major	780,690	1.19%	4.2%
Rbt (sp): efficiency below requirements	16	Brakes	Major	728,150	1.11%	3.9%
Registration plate lamp(s): inoperative in the case of a single lamp or all lamps	17	Lights, reflectors and electrical	Major	721,994	1.10%	3.9%
Track rod end: ball joint has excessive play	18	Steering	Major	699,573	1.07%	3.7%
Malfunction indicator lamp: inoperative or indicates a malfunction	19	Noise, emissions and leaks	Major	623,494	0.95%	3.3%
Headlamp aim: too high	20	Lights, reflectors and electrical	Major	578,033	0.88%	3.1%
Shock absorbers: has a serious fluid leak	21	Suspension	Major	548,631	0.84%	2.9%
Washers: not working	22	Driver's view of the road	Major	540,949	0.83%	2.9%
Exhaust system: has a major leak of exhaust gases	23	Body, chassis and structure	Major	508,492	0.78%	2.7%
Service brake performance: excessively binding	24	Brakes	Major	473,797	0.72%	2.5%
Linkage ball joint dust cover: ball joint dust cover no longer prevents the ingress of dirt	25	Suspension	Major	453,550	0.69%	2.4%
Linkage ball joints: ball joint excessively worn	26	Suspension	Major	446,426	0.68%	2.4%
Rigid brake pipes: excessively corroded	27	Brakes	Major	435,464	0.66%	2.3%
Brake discs: significantly and obviously worn	28	Brakes	Major	395,728	0.60%	2.1%
Condition: has a tear, caused by separation or partial failure of its structure	29	Tyres	Dangerous	369,608	0.56%	2.0%
Catalyst emissions: Lambda reading after 2nd fast idle outside specified limits	30	Noise, emissions and leaks	Major	349,989	0.53%	1.9%

Where DVSA uses the same wording under several defect codes, the commonest code is shown. Category is DVSA's deficiency category.

Failures by area

DVSA data

Share of failed MOT tests with a failure in each area
Area	Failed tests with a failure here	Share of failed tests
Lights, reflectors and electrical	7,302,695	39.1%
Suspension	5,816,370	31.2%
Brakes	4,443,267	23.8%
Tyres	4,195,007	22.5%
Driver's view of the road	3,100,363	16.6%
Body, chassis and structure	2,261,891	12.1%
Noise, emissions and leaks	2,064,198	11.1%
Steering	1,243,166	6.7%
Seat belts and airbags	665,630	3.6%
Road wheels	241,800	1.3%
Registration plates and VIN	231,352	1.2%
Speedometer and driving controls	3,028	0.0%

Failures an owner can often spot first

DVSA dataMany of these are a blown bulb, worn wiper blades or an empty washer bottle. Some, such as a cracked windscreen or wiring faults, need a garage.

Failed MOTs whose only failures were lamps or the driver's view
Failed tests where every failure was in…	Tests	Share of failed tests
Lights, reflectors and electrical	3,007,761	16.1%
Lights, or the driver's view of the road	4,469,792	24.0%

Method

Source: DVSA's anonymised MOT tests and results for 2023-01-01 to 2024-12-30, published under the Open Government Licence v3.0. 73 Auto counted every record itself; no figure is taken from a secondary report.

Scope: class 4 vehicles (cars and light vans), normal tests only (retests excluded), vehicles at least 2.5 years old at test, whose make matches 73 Auto's vehicle catalogue: 65,477,892 tests in 2023–24.

First-time pass rate: the share of normal tests with the result Pass. A test where a defect was fixed at the station and the car passed the same day (PRS, pass after rectification) counts as an initial fail, as DVSA counts it.

Failure areas and items: a test counts once for an area or item if it had at least one fail-level (Major or Dangerous, or pre-2018 fail) defect in it, however many locations were affected. Advisories and minor defects are not failures.

Share of failed tests uses every normal test that did not pass first time (fail or PRS) as the base. A test with the same defect at two locations counts once.

Publication test: The 30 commonest fail items by wording, each with 10,000+ tests. Items shown: 30 (minimum 30); Failed tests: 18,656,905 (minimum 1,000,000).

Limitations

DVSA's defect wordings changed in May 2018; older and newer wordings for the same fault are listed separately where both occur.

The share of failed tests is not the share of fails caused by a defect alone: most failed cars have more than one defect.

An MOT result records a car's condition on test day. Servicing, owners' habits, annual mileage and where the car is driven all affect it, so a low failure rate is not proof of mechanical reliability or build quality.

Citing this study

Cite as: 73 Auto, “The most common reasons cars fail the MOT”, 2026-09-28, https://73auto.com/research/most-common-mot-failures. Based on DVSA anonymised MOT tests and results, Open Government Licence v3.0. The data behind every table is free to reuse with attribution.

More MOT studies

UK MOT statistics 2023–24 · 28.5% of UK MOT tests in 2023–24 did not pass first time: 18,656,905 of 65,477,892 tests (DVSA data).
Which car makes fail the MOT most? A ranking adjusted for age and mileage · Of the 21 car makes with over a million MOT tests in 2023–24, BMW cars failed 24% less often than comparable cars of the same age, mileage and fuel (73 Auto analysis of 3,694,719 DVSA tests).
The cars that fail the MOT least and most, class by class · Of 190 models with 20,000+ MOT tests, the BMW M3 had the lowest failure ratio against cars of the same age, mileage and fuel (0.41, 31,544 tests, 2023–24).
How MOT pass rates fall with age and mileage · 87.1% of 3-year-old cars passed their first MOT first time in 2023–24, against 67.5% of 10-year-old cars (DVSA data, 3,907,416 and 4,163,623 tests).
Which MOT failures rise most as cars get older · Steering failures rise the most with age: 0.13% of MOT tests on 3-year-old cars against 3.4% at 15 years, 26 times as often (DVSA data, 2023–24).
MOT failure rates by test area: brakes, tyres, lights and more compared · Lights, reflectors and electrical is the MOT area cars fail on most: 11.2% of all tests and 39.1% of failed tests (2023–24, DVSA data).
Dangerous MOT defects: how many cars have them and what they are · 5,141,819 MOT tests in 2023–24 found at least one dangerous defect: 7.9% of all tests, about 1 in 13 (DVSA data).
Petrol vs diesel vs hybrid: MOT pass rates compared · At ages 3–10, 85.6% of hybrid MOT tests passed first time, against 79.6% for petrol and 75.5% for diesel (DVSA data, 2023–24).
Electric car MOT statistics: how EVs compare with petrol and diesel · 83.5% of MOT tests on electric cars aged 3–10 passed first time in 2023–24, against 79.6% for petrol cars of the same ages (DVSA data, 330,180 EV tests).

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Where these figures come from

Anonymised MOT tests and results, 2023 and 2024 — Driver and Vehicle Standards Agency (DVSA). Open Government Licence v3.0.

Figures labelled as 73 Auto estimates are our own analysis of these sources, set out in the methodology and data sources. To report a factual error, see corrections.