The MOT Test checks list – overview

The MOT Test checks list section is a complete list and description of the checks your vehicle will undergo during its MOT Test. While this list groups the checks under each component, the Tester will carry out the checks in a specific sequence designed to save time, Testing all under-vehicle items or under-bonnet items at the same time for example.

Bear in mind that a Tester may not fail an item if it is within the limits set by DVSA – if it is dangerously close to failing but still within limits the Tester must still pass it, but may give the vehicle an ‘Advisory’ notice. For your own and other road users’ safety you are urged to take urgent notice and act on any advisory items you may find on your certificate. (See ‘New MOT failure definitions’ below).

If you want to ask an MOT Tester about a specific problem, first register on the MOT Forum, then ask your question in the appropriate section.

Links to all MOT Tests | MOT Test Descriptions

List of MOT Test Checks

This is a description of MOT checks made during an MOT inspection.

It is designed to give you a better understanding of the MOT and to enable you to carry out some simple checks for yourself before taking your car for its MOT.

The following list of MOT checks will tell you which parts of your car are inspected, how the pass or fail result may differ from previous MOT inspections and tells you about some new items which have been added to the MOT Test.

The biggest changes will be to your MOT Test result document – MOT defects will now fall into one of three categories:

Your car may pass with no defects at all, or with one or more ‘minor’ defects – it is still a pass.

If your car has one or more ‘major’ or ‘dangerous’ defects, it is a fail.

*A “dangerous” note on your MOT failure document is informing you clearly in writing that your vehicle is not safe to drive.

Additionally, your car may pass with no ‘defects’ at all, but still carry an ‘advisory’ note from the Tester if he discovers something which may not be part of the MOT Test, but nevertheless is something you should be aware of.

From 6 February 2023, if a tester uses the defect ‘item not tested’, the reason for selecting this defect must be explained in the additional information box. This applies to all classes of vehicles.

Click here for an item by item description of the MOT.

Further information: The online MOT Tester’s Manual.

Contains public sector information licensed under the Open Government Licence v3.0.

MOT Test Check List: What’s Checked on an MOT

Every vehicle over 3 years old in the UK must undergo an annual MOT test to ensure it meets road safety and environmental standards xpressgarage.co.uk. The MOT is not a general engine or mechanical health check – for example, the condition of the engine, clutch, or gearbox isn’t inspected gov.uk. Instead, the test focuses on essential components related to safety (like brakes, lights, tyres) and emissions. In fact, the most common reasons for MOT failures are typically issues with lights or signals, suspension faults, brake defects, and tyre problems confused.com.

Below is a comprehensive MOT test checklist, organised by vehicle area, so you know exactly what is checked on an MOT. Use this MOT check list to understand which parts of your car will be inspected and ensure your vehicle is ready for its MOT.

Vehicle Identification (VIN & Registration Plates)

Vehicle Identification Number (VIN): The tester will check that a single, legible VIN is permanently displayed on vehicles first used on or after 1 August 1980 gov.uk. The VIN plate should not be missing or tampered with – a missing or non-matching VIN can result in a refusal to test.

Registration Plates: Both the front and rear number plates must be present, secure, and in good condition gov.uk. The plates are checked for the correct colour (white front, yellow rear) and that the characters are legally formed and spaced gov.uk. Any significant damage, fading, or incorrect fonts/spacing on a number plate can lead to a failure. The tester also verifies that the registration plate illumination lamp is working, as the rear plate must be lit at night xpressgarage.co.uk. It’s wise to ensure your plates are clean and the plate bulbs are working before the test.

Brakes

The MOT includes a thorough test of the vehicle’s braking system performance and condition. The tester will use equipment to measure brake efficiency and balance. This means the service brakes (foot brake) must demonstrate adequate stopping force and even braking across wheels, and the parking brake (handbrake) must hold the vehicle securely. The condition of brake components is inspected – for example, checking for worn, damaged or missing brake pads or discs, and looking for any brake fluid leaks or corroded brake lines gov.ukgov.uk. If a brake pad is dangerously worn or a brake disc is missing (e.g. due to improper repair), it’s a Major defect gov.uk.

Modern vehicles have electronic systems that are also checked. The tester will confirm that the anti-lock braking system (ABS) and electronic stability control (ESC) (if fitted) warning lights turn on and then off as they should, indicating those systems are functional gov.uk. A dashboard warning lamp that remains lit for ABS or ESC signifies a fault, which is usually an MOT failure (Major defect) gov.uk. Similarly, vehicles with an electronic parking brake or brake fluid level warning lamp will fail if those warning lights indicate a malfunction gov.uk. In short, any issue that significantly affects braking performance or safety – whether mechanical (like poor performance or imbalance) or electronic (warning light on) – will need fixing to pass the MOT gov.ukgov.uk.

Steering

The MOT test of the steering system covers the steering wheel, column, rack-and-pinion or steering box, and associated linkages for wear or damage. The steering wheel itself must be securely attached and not so loose as to cause concern. The tester checks for excessive free play in the steering – joints and bearings shouldn’t be excessively worn. The power steering system (if the car has power or electric steering) is inspected for proper function: the steering should turn smoothly without undue stiffness or play, and hydraulic power steering fluid levels should be adequate (no obvious leaks in the system) gov.uk. Any leaks from power steering pipes or hoses, or corrosion that could cause failure, can result in a fail gov.uk.

The MOT also ensures any steering lock or anti-theft steering device engages and releases correctly if the vehicle is equipped with one gov.uk. For example, if your car’s ignition key is removed, the steering lock (on cars that have this feature) should engage; a faulty steering lock can be a reason for failure. Additionally, the dashboard power steering warning light (or steering assistance fault lamp) is checked – if illuminated indicating a fault, that would typically result in a failure gov.uk. In summary, the steering must be in good condition, securely mounted, and operate reliably; any significant play, insecurity, or warning of failure in the steering system will cause an MOT fail.

Visibility (Windscreen, Wipers, Washers, Mirrors & Bonnet)

Good driver visibility is crucial for safety, so the MOT includes checks on anything that might hinder your view of the road. The windshield (windscreen) is inspected for cracks, chips, or damage, especially in the driver’s field of view. Damage larger than 10mm in the area directly in front of the driver (the “A-zone” about 290mm wide) will typically cause a fail, as will any chip or crack 40mm or larger in the swept area of the screen theaa.com. The tester will ensure the windscreen is in good condition and that there are no stickers or obstructions impeding the driver’s view beyond the allowed tolerance.

The windscreen wipers must work properly and be in good condition (no splits or missing chunks on the blades) so they can clear the screen effectively gov.uk. Likewise, the washer jets must spray sufficiently – a washer system that doesn’t dispense fluid is a common MOT failure for poor visibility. It’s important to top up your screenwash and check that the washers are not clogged before the test. The MOT tester will operate the wipers and washers to verify they clear the windscreen enough for a clear view gov.uk.

All rear-view mirrors required on the vehicle are checked for presence, condition, and security gov.uk. This includes the interior mirror and the obligatory exterior mirrors (passenger and driver’s side). The mirrors should not be cracked such that rear vision is significantly obscured, and they must be firmly attached. Missing or badly damaged mirrors can lead to a failure, since a driver must have the minimum required views to the rear and sides gov.uk.

An often overlooked item in the visibility category is the bonnet catch. The tester will inspect that the bonnet (hood) can be securely latched gov.uk. This is a safety item – if the bonnet were to fly open while driving, it would severely obstruct your view. Thus, a bonnet that doesn’t latch properly (for example, a broken catch or secondary safety catch) will cause the vehicle to fail. Make sure your bonnet opens and closes securely; if you’ve recently checked your oil, double-check that the bonnet is fully closed afterward.

In summary, the vehicle must allow the driver a clear view of the road: the windscreen should be free of significant damage, wipers and washers must function to keep it clean, mirrors must be intact and correctly mounted, and the bonnet must be secured to prevent sudden opening.

Lights and Electrical Equipment

Nearly all of the vehicle’s exterior lamps and lighting are covered in the MOT, since proper lighting is vital for seeing and being seen. In fact, lighting and signalling issues are one of the top reasons for MOT failures (almost 1 in 5 failing cars have a lighting fault) rac.co.uk. The MOT tester will inspect all required lights on your car for operation, condition, and correct colour. This includes:

• Headlamps (front headlights): Both dipped and main beam must work. The headlamp units are checked for damage, secure mounting, and correct alignment/aim. The beam aim is tested to ensure it isn’t too high or dazzles other drivers. If your car has HID or LED headlights, the tester will also verify any self-levelling or headlamp cleaning devices (washers) are present and functioning, if those were fitted as standard gov.uk. A missing or non-working headlamp washer on vehicles that require them (e.g. some cars with xenon HID lights) can be a fail. The main beam indicator on the dashboard must illuminate when main beams are on gov.uk.
• Side lights (parking lights) and Rear position lamps: These must be operational on both sides. On newer vehicles, daytime running lights (DRLs) are also checked – for cars first used from 1 March 2018, the MOT will include ensuring DRLs (if fitted) are working correctly gov.ukgov.uk (note that most of those vehicles only started needing MOTs in 2021 due to age).
• Indicators and Hazard Lights: All indicator lights (front, rear, and side repeaters) should flash at the correct frequency and be the correct amber colour (or have an amber bulb behind a clear lens). The hazard warning function (all indicators flashing) must also operate. The dashboard tell-tale light for the indicators (the blinking arrow light or sound) should function; a failing tell-tale can result in a minor, but the primary concern is that the external signals work so other road users can see your intentions.
• Brake Lights: All brake lamps, including the high-level brake light (if fitted), must illuminate promptly when the brake pedal is pressed. The tester will have an assistant check or use reflective surfaces to verify brake lights. A non-functioning brake light (or brake light stuck on) is a Major defect. Ensure bulbs are good and there are no bad connections.
• Rear Fog Light: Vehicles post-1986 are required to have at least one rear fog lamp (typically on the driver’s side) that emits a red light. During the MOT, the fog light must switch on via its control and show a dashboard indicator light. A missing or inoperative rear fog lamp is a fail.
• Reverse Lights: From 2018, the MOT now includes a check of reversing lights on vehicles first used on or after 1 September 2009 gov.uk. If you have a newer car (2009+) with one or two reverse lamps, they must come on when reverse gear is engaged. If these don’t work, it can result in a failure.
• Number Plate Light: The rear number plate must be illuminated. The test will fail if the number plate lamp is not working or is missing xpressgarage.co.uk, since the plate needs to be readable at night. This is an easy thing to overlook – a quick bulb replacement is usually all that’s needed if it’s out.
• Reflectors: The rear reflectors (usually incorporated in the tail lamp units or separate reflectors on the rear of the car) must be present and not cracked. They ensure your car is visible when light shines on it in the dark. Missing or broken rear reflectors can cause a fail, so replace them if damaged.

All lights need to be securely mounted and in good condition (e.g. no broken lens that white light shows through where only red should, etc.). The tester will also check that the lights do not have any colouring or tinting that is illegal (for example, tint films on headlights that significantly reduce light output or change the colour from white could be a problem).

Additionally, if your vehicle is equipped with a tow bar and electric towing socket, the MOT includes a test of the trailer lighting socket. The 13-pin trailer electrical socket (or old-style 7-pin) will be checked for correct operation of the trailer lights circuit gov.uk – garages use a plug-in tester to ensure that indicators, brake, tail, etc. would work on a towed trailer. Any wiring should be secure and in good shape to pass.

Tip: Walk around your car before the MOT and double-check every bulb. Having a friend help or looking at reflections can ensure you catch any that are out. Since lighting faults are such a common MOT failure cause, replacing dim or dead bulbs and cleaning foggy lenses ahead of time can save you from an avoidable fail rac.co.uk.

Tyres, Wheels and Suspension

Your vehicle’s tyres and wheels must meet several important standards for the MOT. Tyres are critical for safety, and the tester will check all of them for:

• Tread Depth: The legal minimum tread depth is 1.6mm across the central three-quarters of the tyre’s width, around the entire circumference. Any tyre worn below 1.6mm will fail the MOT theaa.comtheaa.com. It’s wise to replace tyres before they reach this limit. Testers often use a gauge or the tread wear indicators on the tyre to assess this.
• Condition: Tyres should be free from deep cuts, bulges, or visible cord exposure. Damage like nails, bulging sidewalls, or cracks may result in failure if deemed serious. Make sure there are no objects lodged in the tread and no sidewall damage. Even small cuts that reach the tyre cord or fabric are cause for failure.
• Tyre Type and Matching: All tyres must be of a suitable type for the vehicle and the same axle must have tyres of the same construction (you shouldn’t have a radial tyre on one side and a cross-ply on the other, for instance). Unusual tyre sizes or mixes (e.g. winter tyre on one side, summer on the other) could be an issue if they affect safety. As long as they are the correct size and rating for the car and match per axle, it’s fine. The spare tyre, if your car has one, is not inspected in the MOT gov.uk – only the tyres actually mounted on wheels on the car are tested. However, it’s good practice to ensure your spare is roadworthy too.
• Wheel Security and Condition: Wheels (rims) are checked to ensure they are not cracked or severely damaged. All wheel nuts or bolts must be present and tight. If you have locking wheel nuts, ensure the key is available in case the tester needs to remove a wheel (though usually wheels are not removed during an MOT). A missing wheel nut or a seriously damaged wheel can result in failure if it compromises safety.

The MOT also covers the suspension and associated components, since these affect both safety and tyre wear. The suspension is inspected both by visual check and by a “bounce” or shaker test. The tester will look at shock absorbers, springs, suspension arms, linkages, bushings, and joints for any signs of excessive wear, damage or corrosion. For example, a broken coil spring is a common reason for MOT failure in areas with potholes ccmhelp.co.uk. If a spring is cracked or snapped, or a shock absorber is leaking fluid such that it significantly affects damping, it will fail. The tester may also push down on each corner of the car to see if it rebounds correctly (it should not continue to bounce). A car that leans to one side or has an uneven ride height can indicate a suspension problem confused.com. Any suspension component that is excessively worn, fractured, or insecure will result in a fail. Even suspension rubber bushings that are deteriorated to the point of likely failure can be marked as a defect. Additionally, the condition of wheel bearings is checked (usually by rocking the wheels to feel for play) – worn-out wheel bearings can be dangerous and lead to failure if there is excessive roughness or looseness.

Modern vehicles also have a Tyre Pressure Monitoring System (TPMS) if first used on or after 1 January 2012. The MOT will check the TPMS warning light. If the TPMS malfunction indicator stays on, indicating a fault in the system, it can be a reason for failure gov.uk. (Note: A TPMS warning simply for low pressure may not fail you if inflating the tyres solves it – but a system fault or dead sensor causing the light to stay on will typically result in a failed MOT honestjohn.co.uk.) So, ensure your tyre pressures are correct and resolve any TPMS issues before the test.

In summary, all tyres must be legally treaded and in good shape, wheels secured and undamaged, and the suspension system must be intact and functional. Because tyres and suspension take a lot of abuse on UK roads, they account for many MOT failures – nearly 8% of cars fail due to tyres and around 13% due to suspension issues rac.co.ukrac.co.uk. Regularly check your tyre condition and listen for odd suspension noises so you can fix problems early.

Vehicle Structure and Body (Including Doors, Seats, Fuel & Towbar)

The body, chassis, and structure of the vehicle are examined to ensure it’s free from excessive corrosion or damage in specific safety-critical areas gov.uk. The MOT isn’t concerned with cosmetic rust, but any corrosion that weakens load-bearing parts of the car (like sills, suspension mounting points, braking system mounts, etc.) is taken seriously. The rule of thumb is that rust or damage within 30cm of critical components (like seatbelt anchorages or suspension mounting) could cause a fail if it’s more than just superficial. The tester will also feel for sharp edges on the bodywork that could cause injury – any protruding sharp edge (for instance, from a torn body panel or bumper) might need to be fixed gov.uk. In short, the vehicle’s structure must be solid and secure. Significant dents, deformation, or corrosion holes in the wrong places can result in failure, especially if they affect safety.

Doors and openings: All doors must latch securely in the closed position, and front doors should open from both inside and outside the vehicle gov.uk. Rear doors need to open from the outside (locks and handles must function) gov.uk – this is so that in an emergency, passengers can be rescued. The tester will check door hinges, catches, and locks for security and condition. A door that won’t open (or won’t stay closed) is a problem. Also, the boot or tailgate is checked to ensure it can close properly gov.uk (this is referred to as “load security” – a boot lid that can’t secure might allow luggage to fall out). The bonnet we covered under visibility, but it also ties into structure as it must latch. Floorpans are considered part of the body structure – any holes in the floor (especially near seat mounts) could be a fail, so the tester will glance under carpets or from underneath for serious issues.

Seats: The MOT focuses on two main aspects of seats – security and functionality. The driver’s seat adjustment mechanism must work, so that the seat can be secured in different positions (especially important it can lock in the upright position) gov.uk. If the driver’s seat is fixed in position due to a broken adjuster, it might fail. All seats should be securely mounted to the vehicle; the tester will try to move the seat to ensure it’s bolted down properly. Seat backs (especially front seats) must be able to lock in the upright position and not fold down on their own while drivinggov.uk. In practical terms, if you have a folding rear seat, the latch should work, but generally front seat backrests are checked. Loose or wobbly seats are dangerous and will result in a fail.

Fuel System: The fuel system is inspected for any leaks and secure components gov.uk. The examiner will check fuel pipes and hoses under the car and in the engine bay – they should be in good condition, not excessively corroded or damaged, and properly clipped in place gov.uk. Any sign of a fuel leak (smell of petrol or visible dripping) is an immediate fail and also a safety hazard, so ensure there are no leaks. The fuel filler cap is opened to see if it seals correctly – the cap seal and mechanism must secure to prevent fuel leaks gov.uk. If your filler cap requires a key, make sure you provide it so the tester can open the cap gov.uk. A missing or loose fuel cap that doesn’t seal will fail.

Towbar (Towing Equipment): If your car has a towbar, it is part of the MOT check. The towbar’s mounting, nuts and bolts are examined for tightness and corrosion. The towball or hitch mechanism must not be excessively worn or cracked. The tester will look for any inappropriate repairs or modifications to the towbar structure gov.uk – for example, a towbar that’s been welded (when it shouldn’t be) or bodged onto the car could be rejected. They’ll also check that the electrical wiring to the trailer socket is secure and not damaged, and as mentioned earlier, test the towbar electric socket for correct functioning of lights gov.uk. If the towbar is detachable, it should be properly secured in use. A towbar or its electrical socket in poor condition, or any evidence of it being loose, will result in a fail. Additionally, the MOT requires that if a speedometer is present (which it must be on any car with a towbar after 1984 due to construction rules), it should be in good working order gov.uk – this note is included in the towbar section of the manual likely because towing legislation often ties with speed limits, but essentially, a broken speedometer can be a defect (usually minor if it’s just not indicating correctly, but it should function).

In summary, the vehicle’s body and attached components must be structurally sound. Doors must open and close safely, seats must be secure, the fuel system must not leak, and any towing equipment must be properly attached and functional. Any serious weakness or insecurity in these areas – such as a corroded sill with a hole, a loose seat, a door that won’t open, a fuel leak, or a dangerous towbar – will cause an MOT failure gov.ukgov.uk.

Seatbelts & Other Safety Equipment

All seat belts fitted to the car are checked for their condition and operation. The tester will verify that each mandatory seatbelt is present, in good condition (no significant fraying or cuts), and that it latches securely into its buckle gov.uk. They will give the belts a sharp tug to see that the inertia-reel mechanism locks properly (though note, some rear belts only lock under vehicle movement, which the tester will be aware of) mattersoftesting.blog.gov.uk. If a seat belt is cut, excessively worn, or will not retract or lock as intended, it will fail. All seatbelts must be the correct type for the vehicle and seating position (for example, you cannot remove an original three-point belt and replace it with a lap belt – that would not meet standards). The MOT also covers seatbelt anchor points – if there’s serious corrosion where the belt mounts to the car, that’s a fail for structure (as mentioned above). Also, child seat warning: if you have a child car seat fitted, it’s best to remove it before the MOT so the tester can fully inspect belts. A tester is not allowed to dismantle or remove child seats, which might restrict belt checks.

If the vehicle has Supplementary Restraint Systems (SRS) such as airbags, seat belt pretensioners, or seat belt load limiters, the warning lights for these will be checked gov.uk. On modern cars, when you turn the ignition on, the dashboard SRS or airbag light should briefly illuminate and then extinguish, indicating the system has no fault. If the airbag (SRS) warning lamp remains lit (or doesn’t light at all), it indicates a fault in the system. A lit airbag/SRS warning light is usually a Major defect, meaning an MOT fail rac.co.uk. This is a change from many years ago; it’s now clear that an airbag system fault will cause failure, so you cannot ignore that airbag light. The same goes for seatbelt pretensioner warnings – many cars use the same SRS light for airbags and belt tensioners. If it’s on, you’ll need to fix the issue (which could be as simple as a bad sensor or connection) to pass the MOT.

Other “safety equipment” items checked include the horn, which must be present and of a correct type (a continuous tone horn, not a musical or multi-tone horn) and it must function properly gov.uk. The tester will press the horn button to verify it makes an audible sound. A non-working horn or inappropriate noise (e.g. an aftermarket siren) is a fail.

The speedometer (speedometer head) should be fitted and functioning. The MOT will fail a vehicle if the speedometer is missing, not illuminated (if it can’t be read in the dark), or obviously in error. Generally, as long as your speedo works and isn’t completely off (or stuck), it’s fine – speedometers rarely cause MOT fails unless broken or unreadable. Note that if your speedometer has a shattered glass or inoperative dial, that’s something to address.

If the car has an anti-theft or immobiliser system that was standard, the MOT may check that it hasn’t been removed or disabled in a dangerous manner. For example, a steering column lock (anti-theft device) is required on cars first used after Sept 2001, and if missing, it might be noted. However, this is rarely an issue in testing; just be aware that obvious tampering with required immobilisers/alarms could be a problem if it affects the vehicle’s ability to be safely tested.

Finally, the MOT testing now groups checks of various dashboard malfunction indicator lamps (MIL) across different sections. We’ve mentioned some already (airbag, ABS, etc.), but it’s worth summarizing: if your car has warning lights for the airbags/SRS, ABS, ESC (stability control), brake fluid/parking brake, or power steering, the tester will verify these lights function correctly (come on with ignition and then go out). Any of those staying on indicates a fault that usually results in a failure gov.ukgov.uk. One exception is that not all older cars have these systems; the test only applies to vehicles fitted with them (and for engine MIL, only to vehicles from 2003/2008 onward as noted below). In the next section, we will detail the emissions and engine MIL specifically.

Exhaust, Emissions and Noise

The MOT test also ensures your vehicle isn’t overly polluting or unreasonably noisy. The exhaust system is checked front to back. It must be securely mounted, complete (no missing sections) and not have major leaks gov.uk. A small exhaust leak might not fail if it doesn’t affect noise or emissions, but any blowing exhaust that results in excessive noise or could leak fumes dangerously will need repair. The tester will examine the exhaust including the catalytic converter if one was originally fitted – a missing or clearly tampered-with catalytic converter is a fail (Major defect) on any car that originally had one gov.ukgov.uk. In other words, you cannot remove the cat or diesel particulate filter just to improve performance; that’s illegal and the MOT will catch it. Likewise, any other emissions control device (EGR valve, oxygen sensor, DPF, etc.) visibly missing or disconnected is a fail gov.ukgov.uk.

Emissions testing: Depending on your car’s age and fuel type, the MOT center will perform an emissions test. For petrol cars, this usually means a probe in the tailpipe to measure CO (carbon monoxide) and HC (hydrocarbons), and sometimes CO₂ and lambda (air-fuel balance) if a catalytic converter test is required. The car must meet the limits for its age category – older cars have more lenient limits, while cars with a cat must meet stricter “CAT test” limits gov.ukgov.uk. For diesel cars, the test is typically a smoke opacity test: the car is revved and the opacity of the exhaust smoke is measured. As of 20 May 2018, stricter rules for diesel emissions apply, especially for diesels with a DPF (Diesel Particulate Filter). If the tester sees any visible smoke of any colour from a modern diesel’s exhaust, it is a Major defect (fail) gov.ukgov.uk. Additionally, if there is any evidence the DPF has been removed or tampered (for example, cut open and gutted), that’s an automatic fail gov.uk. Diesel smoke limits are quite strict for newer cars; even a moderate puff of black smoke might fail a car that should have “zero visible smoke”. Owners of diesels should ensure the car is well-maintained – a good run to warm it up fully before the test can help reduce smoke gov.uk.

Cars with engine management warning lights for emissions-related systems are now included in the MOT. Specifically, if the Engine Malfunction Indicator Lamp (MIL) – often the “check engine light” – is illuminated on the dashboard, it will generally cause a fail on cars first used from 1 July 2003 (petrol) or 1 July 2008 (diesel) onward rac.co.uk. The tester will check that the engine MIL comes on with the ignition and then goes out once the engine is running gov.ukgov.uk. A car with its check-engine light on is classed as having a Major defect in the MOT rac.co.uk because it indicates a likely emissions-control fault. If you have an older car where this light isn’t applicable, that’s fine; but for modern vehicles, you’ll want to fix any engine management issues (such as lambda sensor faults or catalytic converter efficiency problems that trigger the light) before the MOT. Keep in mind that if the MIL is on but the emissions tailpipe test still meets the limits, it still fails due to the light – the presence of the fault code itself is the issue.

The MOT tester will also assess exhaust noise. The car should not be unreasonably louder than a standard vehicle of its type gov.uk. If you have a loud aftermarket exhaust with no silencers and it’s blatantly much noisier than normal, the tester can fail it for noise. Generally, as long as you have some form of silencer and it’s not outrageously loud, it’s okay – but if you’ve removed the mufflers or have a racing exhaust, be aware of this rule gov.uk. The tester will use judgement; there’s no precise decibel limit in the MOT, but any excessively loud exhaust is a problem gov.uk. This goes hand-in-hand with checking that all parts of the noise suppression system (silencers, resonators) are intact and secure.

Finally, the tester checks for fluid leaks that could be harmful – for example, fuel or oil leaks that are seen as a serious environmental risk. Significant leaks (not just minor dampness or drips, but anything actively leaking or pooling) can result in a failure under the new rules gov.uk. This typically refers to things like a fuel leak, or hydraulic fluid leak, or even coolant leak if it’s severe. A few drops of oil might get an advisory at most, but a big leak will fail. Make sure there are no major leaks from your engine, transmission, or other components when you go for the test.

Summary of emissions/noise: Your car must meet the emissions standards for its age – the MOT will check exhaust gases or smoke. Keep your emissions equipment in place (catalysts, DPFs) and fix that check-engine light if you have one on. The exhaust system should be intact and not excessively loud or leaking. By maintaining your car (regular services can catch emissions issues early), you’ll avoid most of the pitfalls in this section. Remember, a car that fails on “emissions” is often not running correctly and could be polluting more than allowed, so it’s both a legal and environmental concern to resolve it.

Dashboard Warning Lights and Electrical Checks

As mentioned throughout this checklist, a variety of dashboard warning lights are now part of the MOT assessment. Here is a consolidated list of the main indicator lamps that are scrutinized and what a tester expects to see:

• Airbag/SRS Warning Light: Should go out after the car is started. If it stays on (indicating a fault in the airbag or seatbelt pretensioner system), it’s likely a fail rac.co.uk.
• ABS Warning Light: Should illuminate then extinguish. A continuous ABS light means the anti-lock brakes have a fault – MOT fail gov.uk.
• ESC (Electronic Stability Control) or ESP Light: If fitted (required on most cars from 2014), it should go out after start up. A lit ESC fault light is a fail gov.uk.
• Brake System Warning Lamp: This could be the same as the handbrake light on many cars. If it indicates low brake fluid or other brake system fault and stays on (when handbrake is off), that’s a fail gov.uk. Make sure your brake fluid is topped up and that the handbrake switch isn’t sticking.
• Electronic Parking Brake (EPB) Light: If your car has an electronic handbrake, a warning here would be treated similarly – it should not indicate a fault.
• Power Steering Warning Light: For cars with electronic power steering, a warning lamp that stays on is a fail since it signals a problem with steering assistance gov.uk.
• Engine Management Light (EML): As detailed above, for petrol cars 2003+ and diesels 2008+, an illuminated engine MIL is a Major defect and causes failure rac.co.uk. Essentially, if your car is new enough to have an engine light, it must be off during the test (after the initial bulb check).
• Tyre Pressure Monitoring System (TPMS) Light: On cars after 2012, if the TPMS warning lamp indicates a system fault (stays on continuously), it can lead to failure gov.ukhonestjohn.co.uk. Make sure your tyres are inflated and reset the TPMS if needed. (A TPMS lamp that is on because a tyre is simply under-inflated should turn off after correcting the pressure; if it doesn’t, there may be a sensor fault).
• Beyond warning lights, general electrical checks include things like the condition of visible wiring and the battery mounting gov.uk. While the MOT isn’t going to run a full electrical test, the examiner will note if the battery is insecure or if there are exposed wires that might be a safety issue. The battery should be secure in its tray and not leaking.
• All the other electrical bits such as lights, horn, wipers we’ve covered. The alternator charging system isn’t explicitly tested, but indirectly, if your battery light stays on indicating a charging fault, that’s not strictly a test item – however, it’s wise to address it as it could lead to breakdown.
• In short, your dashboard should ideally be free of any persistent warning lights when the car is running. If you have an MOT coming up, it’s worth plugging in a diagnostic tool or visiting a mechanic to clear any fault codes and fix the underlying issues. The MOT testers now have clear guidance to fail cars with certain warning lights lit, as these indicate that safety systems are not working as intended.

• Conclusion: This MOT test checklist covers all the key components and systems that are inspected during a Class 4 MOT (standard car MOT). By understanding what is checked – from lights and brakes to structure and emissions – you can better prepare your vehicle. Many MOT failures are due to simple things that could be fixed beforehand (blown bulbs, worn tyres, etc.), so it pays to do a thorough pre-MOT check yourself or have a mechanic do a quick inspection. Always use quality replacement parts and maintain your car well; an MOT is a minimum safety standard, and while passing it means your car met the standard on the day of the test, regular maintenance is crucial year-round xpressgarage.co.ukxpressgarage.co.uk.
• If your vehicle does fail, you’ll receive a list of defects. You must repair Major or Dangerous defects to make the car roadworthy and legal. You can retake the MOT after fixes – often garages offer a free retest within a certain timeframe for failed vehicles. Remember that driving with a known Dangerous defect is illegal gov.uk, and driving without a valid MOT (if required) can result in fines up to £1,000 gov.uk.
• By following this comprehensive MOT checklist and addressing any issues in advance, you’ll improve your chances of passing first time. Safe motoring!
• References & Sources: This article has been updated using official UK government and DVSA guidance on MOT checks and regulations, as well as trusted motoring resources for drivers. For more detailed information, you may refer to the official [MOT Inspection Manual for cars】gov.uk and [government MOT guidance for motorists】gov.ukgov.uk. The information is current as of the latest MOT rules in 2025 and reflects the standards of an authoritative motoring resource in the UK.