The most common reasons UK cars fail their MOT

From 27,338,585 individual failure items recorded across 58 million MOT tests in 2024. These aren't the number of cars that failed; each failed car can have multiple failure items. Here's where the problems cluster.

Lights

7,048,058

25.8% of all

Suspension

5,705,635

20.9% of all

Brakes

3,323,584

12.2% of all

Tyres

3,017,505

11.0% of all

Wipers & glass

3,464,312

12.7% of all

Steering

1,347,360

4.9% of all

Lighting is the biggest single category: 7,048,058 failure items, 25.8% of the total. Missing bulbs, dead registration plate lamps, and headlamp aim account for most of it. The irony is these are often the cheapest to fix. A bulb is under £10, headlamp alignment under £30. A two-minute walk-around check with someone pressing the pedals could catch most of these before the test.

Suspension and springs are the expensive ones. Worn bushes, fractured springs, and damaged shock absorbers generated 5,705,635 failures (20.9%). These aren't DIY fixes. Expect £150–£400 per component at a garage. Cars with high mileage or that have been driven on poor roads are most affected. Sites like BookMyGarage let you compare garage prices online.

Brakes come third at 3,323,584 failures (12.2%). Worn pads and discs are the usual culprits. Repair costs vary widely. Budget £100–£300 per axle depending on the car.

Tyres are fourth but the easiest to prevent. 3,017,505 failures from worn tread, damage, and visible cords. Unlike suspension, tread depth is something you can check yourself. 1.6mm is the legal minimum, 3mm is recommended. A new set costs £200–£500 depending on size. You can check tyre prices at Black Circles.

Want to know which failures affect your specific car? Check the common problems by make or search for your model's MOT data.

All 50 failure reasons, ranked

From 27,338,585 individual failure items in 2024.

#	Reason	Count	% of all
1	a suspension pin, bush or joint excessively worn	2,005,050	7.3%
2	a rear registration plate lamp or light source missing or inoperative in the case of multiple lamps or light sources	1,574,433	5.8%
3	windscreen or window damaged or seriously discoloured but not adversely affecting driver's view	1,421,945	5.2%
4	tyre tread depth not in accordance with the requirements	1,267,267	4.6%
5	a suspension joint dust cover severely deteriorated	1,098,132	4.0%
6	a tyre seriously damaged	1,092,938	4.0%
7	the aim of a headlamp is not within limits laid down in the requirements	966,874	3.5%
8	a spring or spring component fractured or seriously weakened	893,834	3.3%
9	a lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning	887,660	3.2%
10	a brake lining or pad worn below 1.5mm	834,830	3.1%
11	a transmission shaft constant velocity joint boot severely deteriorated	815,970	3.0%
12	wiper blade missing or obviously not clearing the windscreen	746,763	2.7%
13	a suspension joint dust cover missing or no longer prevents the ingress of dirt etc	730,844	2.7%
14	windscreen washers not working or not providing sufficient fluid to clear the windscreen	670,831	2.5%
15	a tyre cords visible or damaged	657,300	2.4%
16	headlamp reflector or lens slightly defective	645,610	2.4%
17	wiper blade defective	624,773	2.3%
18	a transmission shaft constant velocity joint boot missing or no longer prevents the ingress of dirt etc	608,413	2.2%
19	stop lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning	540,435	2.0%
20	parking brake efficiency below minimum requirement	535,272	2.0%
21	steering rack gaiter or ball joint dust cover damaged or deteriorated	532,597	1.9%
22	a steering ball joint with excessive wear or free play	514,214	1.9%
23	engine mil illuminated indicating a malfunction	504,754	1.8%
24	a headlamp or light source missing, inoperative or more than ½ not functioning in the case of led	487,343	1.8%
25	the strength or continuity of the load bearing structure within 30cm of any sub-frame, spring or suspension component mounting (a 'prescribed area') is significantly reduced or inadequately repaired	453,220	1.7%
26	brake pipe damaged or excessively corroded	449,969	1.6%
27	significant brake effort recorded with no brake applied indicating a binding brake	425,854	1.6%
28	exhaust system leaking or insecure	415,127	1.5%
29	a shock absorber damaged to the extent that it does not function or showing signs of severe leakage	378,335	1.4%
30	a rear registration plate lamp or light source missing or inoperative in the case of a single lamp or all lamps	357,831	1.3%
31	brake disc or drum significantly and obviously worn	315,772	1.2%
32	obligatory mirror or device slightly damaged or loose	315,555	1.2%
33	steering rack gaiter or ball joint dust cover missing or no longer prevents the ingress of dirt etc	300,549	1.1%
34	lamp emitted colour, position or intensity not in accordance with the requirements	292,798	1.1%
35	a direction indicator lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning	274,043	1.0%
36	parking brake inoperative on one side	244,390	0.9%
37	brakes imbalance across an axle such that the braking effort from any wheel is less than 70% of the maximum effort recorded from the other wheel on the same axle.	217,861	0.8%
38	lambda coefficient outside the default limits or the range specified by the manufacturer	217,039	0.8%
39	vehicle structure corroded to the extent that the rigidity of the assembly is seriously reduced	199,092	0.7%
40	a lens defective which has no effect on emitted light	190,321	0.7%
41	an obligatory rear fog lamp missing, or a front or rear fog lamp inoperative or in the case of a multiple light source more than 1/2 not functioning	184,379	0.7%
42	emissions test unable to be completed	171,689	0.6%
43	a battery insecure but not likely to fall from carrier	171,365	0.6%
44	an srs malfunction indicator lamp (mil) indicates a system malfunction	168,468	0.6%
45	warning device shows system malfunction	167,411	0.6%
46	a lamp with a multiple light source up to 1/2 not functioning	162,308	0.6%
47	emissions levels exceed default limits	161,271	0.6%
48	parking brake efficiency less than 50% of the required value	152,101	0.6%
49	excessive fluctuation in brake effort through each wheel revolution.	147,535	0.5%
50	a suspension component excessively damaged or corroded	146,220	0.5%

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MOT data from DVSA anonymised test results, 2024 test year. Crown copyright, OGL v3.0. Pass rates are statistical summaries, not assessments of individual vehicle safety.