09/02/2019
No motorist looks forward to the dreaded MOT test, especially the possibility of a failure. It often brings unwelcome surprises and unexpected expenses. However, understanding the different types of faults that can lead to an MOT failure is your best defence. By knowing what to look out for, you can proactively address potential issues, saving yourself time, money, and stress down the line. This comprehensive guide will break down the categories of MOT defects, explain their implications for your vehicle, and provide essential tips to help you sail through your next test.
Understanding MOT Defect Categories
When your vehicle undergoes an MOT test, any issues identified by the examiner are categorised based on their severity. These categories are crucial as they determine whether your vehicle passes or fails, and what immediate actions you need to take. The three primary defect categories are Minor, Major, and Dangerous.
Minor Defects: The Warning Signs
Minor MOT defects are relatively small issues that, while noted, are not serious enough to cause your vehicle to fail its MOT. Think of them as early warning signs – minor concerns that should be addressed soon, even if they don't pose an immediate risk to safety or roadworthiness. Your car will still pass the test if it only has minor defects, but these faults will be recorded on your MOT certificate. Ignoring them can lead to them escalating into more serious, and costly, problems over time.
Major Defects: The Failure Point
Major defects signify more serious issues that have a direct impact on your vehicle's safety, environmental emissions, or overall roadworthiness. If your car is found to have one or more major defects, it will unfortunately fail its MOT test. While these faults might not prevent your car from moving, they compromise its ability to operate safely and legally on public roads. Should your vehicle be deemed to have major defects, it will need to be repaired and then retested before it can legally return to the road. Driving a vehicle with a failed MOT and major defects, especially if your previous MOT certificate has expired, is illegal and can result in significant penalties.
Dangerous Defects: Immediate Prohibition
Dangerous defects are precisely what their name implies: faults that make your vehicle unequivocally unsafe to drive. If a dangerous defect is identified during your MOT, your vehicle not only fails the test instantly, but you are also legally prohibited from driving it on public roads until the issue is rectified. These types of faults pose an immediate and severe risk to you, your passengers, and other road users. Common examples include severely compromised braking systems or steering components that could lead to a complete loss of control. In such cases, the test centre will not allow you to drive the vehicle away; it must be repaired on site or transported via a recovery truck. This strict measure is in place for public safety.
Common MOT Faults Explained
To give you a clearer picture, let's delve into some of the most common faults found during MOT tests, categorised by their severity. Understanding these can help you perform simple checks before your test, potentially preventing a failure.
Common Minor Faults
These faults won't cause a failure but are crucial indicators that attention is needed. They are recorded on your certificate as 'advisories'.
| Minor Fault | Description & Implication |
|---|---|
| Windscreen Washer Not Spraying Properly | If the jets are partially clogged or the fluid level is low, it won't fail your MOT. However, clear visibility is paramount, especially in adverse weather, so it's a quick and essential fix to ensure safety. |
| Worn Wiper Blades | Wipers that leave streaks or miss patches on the windscreen are flagged as minor. While they might still clear some of the screen, their effectiveness is compromised, reducing visibility in rain. Cheap to replace, vital for clear vision. |
| Slightly Worn Tyres (Above Legal Limit) | Tyres nearing the 1.6mm legal tread depth minimum will be noted. They still meet the minimum requirement, but their performance in wet conditions is reduced, and they will need replacing soon to maintain optimal grip and roadworthiness. |
| Cracked Number Plate (Still Readable) | A number plate with minor cracks, as long as all characters are clearly visible and correctly spaced, is a minor issue. However, damage can worsen, potentially obscuring characters and leading to a major defect or a fine. |
| Faded or Slightly Damaged Reflectors | Rear reflectors that are somewhat cloudy or chipped but still adequately reflect light are considered minor. Their primary function is to make your vehicle visible in low light, so ensure they are clean and functional. |
| Loose or Noisy Exhaust Mounts | A slight rattle from the exhaust due to a worn mount isn't dangerous yet, but it indicates wear in the exhaust system. It can become a major issue if the exhaust detaches or leaks, affecting noise levels and emissions. |
| Minor Fluid Leaks (Not Dripping) | Slight misting or dampness around pipes or joints that isn't actively dripping fluid is a minor observation. However, any fluid leak can indicate a developing problem that needs monitoring to prevent more significant, and potentially dangerous, fluid loss. |
| Loose Trim or Panels | Exterior trim or panels that are starting to come loose but are not in danger of falling off are typically marked as minor. While not affecting mechanical operation, they can pose a hazard if they detach at speed or cause sharp edges. |
Common Major Faults
These issues will result in an MOT failure and must be repaired before your vehicle can legally return to the road.
| Major Fault | Description & Implication |
|---|---|
| Tyres Below the Legal Tread Depth | If any tyre's tread depth is below the 1.6mm legal limit, it's an immediate fail. Insufficient tread severely compromises braking distance and grip, especially in wet conditions, posing a significant safety risk. |
| Brake Pad Wear Beyond the Limit | Brake pads that are excessively thin cannot provide adequate stopping power. Even if the brakes feel okay to the driver, they fail to meet safety standards, leading to a major defect due to reduced braking efficiency. |
| Broken or Non-Working Headlights | A failure of dipped or main beam headlights, or incorrect alignment that dazzles other drivers, will result in a major defect. Adequate lighting is essential for visibility and ensuring your vehicle can be seen by others. |
| Suspension Wear or Damage | Worn-out springs, bushes, or shock absorbers significantly affect vehicle handling, stability, and comfort. Suspension issues can compromise control, particularly during cornering or braking, and are a serious safety concern. |
| Handbrake Not Holding Properly | A handbrake that fails to adequately secure the vehicle on a slope is a critical safety issue. This can lead to uncontrolled vehicle movement, especially when parked on inclines, and is an immediate fail. |
| Excessive Emissions | If your vehicle emits more carbon dioxide (CO2) or other pollutants than allowed for its age and fuel type, it will fail. This indicates issues with the engine's combustion or emission control system, impacting air quality. |
| Steering Rack Issues | Loose, worn, or leaking steering components can lead to excessive play in the steering, making the vehicle difficult to control accurately. Any compromise to the steering system is a major safety concern requiring immediate attention. |
| Sharp Edges from Exterior Damage | Rust or damage to the bodywork that creates sharp edges poses a hazard to pedestrians and other road users. Even if the vehicle drives fine, these edges can cause injury and are deemed a major defect. |
| Brake Fluid Leaks | Any discernible leak from the brake system's hydraulic lines or components is a major defect. Loss of brake fluid severely reduces braking performance, potentially leading to complete brake failure and an extremely dangerous situation. |
| Indicators Not Working | If one or more of your vehicle's indicators are not functioning correctly, it's a major issue. Indicators are vital for communicating your intentions to other drivers and pedestrians, preventing accidents. |
Common Dangerous Faults
These faults mean your car is an immediate risk and cannot be driven until repaired.
| Dangerous Fault | Description & Implication |
|---|---|
| Severely Worn or Exposed Tyres | Tyres with bald patches, exposed cords, or significant sidewall damage are critically unsafe. Such tyres are highly prone to blowouts, loss of grip, and hydroplaning, making the vehicle uncontrollable and a severe hazard. |
| Brakes Not Working or Severely Worn | If one or more brakes are entirely non-functional, or the brake pedal goes to the floor, the vehicle lacks critical stopping power. This makes it impossible to safely control the vehicle, posing an extreme risk of collision. |
| Steering Completely Loose or Unresponsive | Excessive play in the steering, or components that have broken loose, means the driver could completely lose control of the vehicle at any moment. This is an immediate and grave danger to all road users. |
| Leaking Fuel System | Any smell of fuel or visible leaks of petrol or diesel from the fuel system is a major fire risk. Such leaks can ignite easily, leading to catastrophic consequences for the vehicle occupants and surrounding environment. |
| Dangerous Corrosion on Suspension or Chassis | Extensive rust that compromises the structural integrity of the vehicle's chassis or critical suspension mounting points makes the vehicle unsafe. It can lead to structural collapse or component failure, especially during impacts. |
| Missing or Broken Seatbelts | Seatbelts that are frayed, missing, or do not latch securely render the vehicle unsafe for occupants. In the event of an accident, seatbelts are crucial for occupant restraint, and their failure puts lives at severe risk. |
| Blown-Out or Cracked Brake Pipes | Brake pipes under pressure can burst if they are cracked, heavily corroded, or damaged. This results in an immediate loss of hydraulic pressure and, consequently, a complete loss of braking ability when it's most needed. |
| Suspension Springs Snapped or Detached | A broken or dislodged suspension spring severely impairs vehicle handling, stability, and control. It can cause the vehicle to lean, bounce erratically, or become unpredictable, significantly increasing the risk of an accident. |
| Completely Failed Lighting Systems | If all front or rear lights are out, or the vehicle cannot be seen in poor visibility conditions, it's too dangerous to be on the road. Lack of proper lighting prevents other drivers from seeing your vehicle, especially at night or in bad weather. |
| Wheels Not Securely Attached | Loose wheel nuts or damaged hubs that pose a risk of a wheel detaching while driving are an immediate dangerous fault. A wheel detaching at speed can lead to a catastrophic loss of control and severe accidents. |
What Happens If My Car Fails Its MOT?
An MOT failure can be frustrating, but the next steps depend entirely on the type of defects identified and whether your current MOT certificate is still valid.
Major Defects and Your Next Steps
If your car receives major defects, it fails the MOT. However, you might still be able to drive it, provided your existing MOT certificate has not yet expired and the vehicle is still considered roadworthy despite the identified issues. This 'breathing room' allows you to take the vehicle for necessary repairs. Once the repairs are completed, you can bring it back to the test centre for a partial retest, often referred to as a 'recheck'. If the repairs are done at the same test centre within 10 working days, the retest might be free or charged at a reduced rate.
Dangerous Defects: An Immediate Prohibition
This is where the situation changes dramatically. If a dangerous defect is flagged during your MOT, the vehicle is legally deemed unsafe to be on the road. You are prohibited from driving it away from the test centre, even if your old MOT certificate is technically still in date. The only legal options are to have the repairs carried out at the test centre itself, or to arrange for the vehicle to be transported away on a recovery truck. Attempting to drive a vehicle with a dangerous defect on public roads is a serious offence, carrying hefty fines and penalty points.
Preventing MOT Failures: A Proactive Approach
The best way to avoid the stress and expense of an MOT failure is through proactive maintenance. Regular checks and servicing can identify minor issues before they escalate into major or dangerous faults. Here's how you can help ensure your car passes with flying colours:
Regular Servicing
Having your vehicle regularly serviced is arguably the most effective way to prevent MOT failures. A professional service (whether interim, full, or major) involves a thorough inspection of your car's vital components, often covering many of the same points as an MOT. This allows mechanics to spot wear and tear early, address fluid levels, check brakes, tyres, and suspension, and ensure your engine is running efficiently, which helps with emissions.
Pre-MOT Checks You Can Do Yourself
Before your MOT, take an hour to perform some basic checks. Many common failure points are easily identifiable:
- Lights: Check all headlights (dipped and main beam), sidelights, brake lights, indicators, fog lights, and number plate lights. Get someone to help you check brake lights.
- Tyres: Ensure tyres are correctly inflated and check tread depth across the entire tyre. Look for any bulges, cracks, or embedded objects. The legal limit is 1.6mm across the central three-quarters of the tread.
- Wipers and Washers: Test your windscreen wipers for streaks or missed areas. Top up your screenwash and ensure the jets spray effectively onto the windscreen.
- Fluid Levels: Check engine oil, brake fluid, power steering fluid, and coolant levels. Low levels can indicate leaks or excessive consumption.
- Horn: Give it a quick blast to ensure it works.
- Seatbelts: Pull each seatbelt out fully to check for fraying or damage. Ensure they retract smoothly and latch securely.
- Visibility: Check your windscreen for chips or cracks, especially those larger than 10mm in the driver's direct line of sight or 40mm elsewhere on the screen.
Listen to Your Car
Your car often gives you clues when something isn't right. Pay attention to any new noises (squealing brakes, rattling exhausts, clunking suspension), changes in handling (pulling to one side, loose steering), unusual smells (burning oil, fuel), or warning lights on your dashboard. Addressing these symptoms promptly can prevent them from becoming major MOT failures.
Frequently Asked Questions About MOT Faults
How much does an MOT cost?
The maximum fee for an MOT test for a car is capped by the government at £54.85. However, many garages offer tests for less than this maximum price, especially if combined with a service.
When does my car need its first MOT?
New cars in the UK do not need an MOT for the first three years from their date of first registration. After this initial period, your vehicle will require an MOT test annually.
Can I drive a car with a failed MOT?
It depends on the type of failure. If your car fails with only 'minor' defects, it still passes the MOT. If it fails with 'major' defects, you can only drive it if your existing MOT certificate is still valid and the car is roadworthy. If it fails with 'dangerous' defects, you cannot drive it on public roads at all, even if your existing MOT certificate is still valid. Driving a car with an expired MOT certificate is illegal, regardless of the defect type, unless you're driving it to a pre-booked MOT test.
What is checked during an MOT?
An MOT test covers around 100 different points on your vehicle, designed to ensure it meets minimum road safety and environmental standards. Key areas include the bodywork and structure, fuel system, exhaust emissions, brakes, tyres and wheels, lights, steering and suspension, seatbelts, windscreen, wipers, and horn. It does not check the engine, clutch, or gearbox's mechanical condition in detail, nor does it involve a general service.
How long does an MOT test take?
An MOT test typically takes between 45 minutes to an hour. However, the total time you spend at the garage might be longer, allowing for administrative processes, waiting times, and any discussions about potential repairs if your vehicle fails.
What's the difference between an MOT and a service?
An MOT is a legal requirement that checks your vehicle's safety and environmental standards at a specific point in time; it's a pass/fail test. A car service, on the other hand, is preventative maintenance designed to keep your vehicle running efficiently and reliably. It involves replacing parts like oil and filters, topping up fluids, and inspecting components for wear, aiming to prevent breakdowns and extend the life of your car. While a service can help your car pass its MOT, they are distinct processes.
Understanding the different types of MOT faults and taking a proactive approach to vehicle maintenance are key to stress-free motoring in the UK. Regular checks, timely servicing, and addressing minor issues before they escalate will not only help you pass your MOT but also ensure your vehicle remains safe, reliable, and legal on the road for years to come.
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