What Does Failing an MOT Mean?
Failing your vehicle's MOT means it does not meet the minimum required environmental and road safety standards set by the Driver and Vehicle Standards Agency (DVSA). Your car will receive a 'refusal of an MOT certificate' notification detailing the reasons for the failure. You cannot legally drive a vehicle that has failed its MOT on public roads, unless you are driving it to a pre-booked appointment for repair or to a pre-booked MOT test. Any driving outside of these circumstances could lead to prosecution.
- Failure means your vehicle is unsafe or does not meet legal standards.
- You'll receive a report detailing the specific reasons for failure.
- Driving a failed vehicle is illegal, except for repairs or retest.
- Repairs must address all 'dangerous' and 'major' defects.
- Minor defects result in advisories, not failure, but should still be addressed.
The DVSA categorises defects found during an MOT into three types: Dangerous, Major, and Minor. A vehicle will fail if it has one or more Dangerous defects, or one or more Major defects. Minor defects are recorded as advisories, meaning they don't cause an immediate failure but should be monitored and repaired to prevent future issues.
Understanding these categories is crucial for preparing your vehicle and avoiding an unexpected trip back to the test centre. The MOT test is designed to ensure all vehicles on the road are safe for their occupants and other road users, and that they comply with emissions standards.
Common Causes for MOT Test Failures
Many common issues can lead to your vehicle failing its MOT, often related to visibility, braking, tyres, and structural integrity. These are the areas inspectors scrutinise most closely. For instance, the condition of your tyres is paramount; under-inflated tyres, tyres with insufficient tread depth (below 1.6mm), cuts, or bulges will result in a failed MOT. This is why regular tyre checks are so important.
Visibility is another critical area. Cracked or damaged windscreens can cause a fail if the damage is within the driver's line of sight, specifically in the 'wipers' swept area of the windscreen. A mot test windscreen chip or crack exceeding 10mm anywhere in that zone, or larger than 40mm elsewhere, will lead to failure. Similarly, faulty lights – broken bulbs, incorrect colour, or misaligned beams – are common reasons for failure, as they directly impact your ability to see and be seen.
Structural and Suspension Defects
Rust and corrosion are also significant MOT failure points. While minor surface rust might be an advisory, excessive corrosion that affects the vehicle's structure, such as on the chassis, body panels near safety-critical components, or suspension mounting points, will lead to a fail. The DVSA's mot rules are stringent on structural integrity to ensure the vehicle can withstand road stresses.
Suspension components, including shock absorbers and springs, are inspected for excessive wear, damage, or leaks. Any significant play in the suspension system or leaking shock absorbers will result in a failed MOT. It's not just about aesthetics; these components are vital for handling and stability.
Braking System Issues
The braking system is one of the most heavily tested areas. Inspectors check for leaks, worn brake pads and discs, malfunctioning callipers, and incorrect brake fluid levels. Any sign of brake fluid leaks, a brake pedal that feels spongy, or excessively worn brake pads will cause a failure. The effectiveness of the braking system is non-negotiable for road safety.
The condition of your vehicle's lights, tyres, and brakes are the most frequent reasons for an MOT failure.
Emissions and Exhaust System Requirements
How can you ensure your vehicle passes the emissions test? The exhaust system is rigorously checked not only for structural soundness but also for its emissions output. A noisy exhaust, significant leaks, or a catalytic converter that is missing or damaged will lead to a failed MOT. The system must be secure, free from leaks, and meet the required emissions standards.
Why do MOT tests include an exhaust emission test? This is to ensure vehicles are not contributing excessively to air pollution and to check that they comply with UK environmental regulations. For petrol vehicles, the test measures carbon monoxide (CO), hydrocarbons (HC), and lambda. Diesel vehicles are tested for particulate matter. If your vehicle emits pollutants above the legal limits, it will fail.
Specific Emission Standards
The exact emission limits vary depending on the vehicle's age and type. For instance, newer vehicles equipped with catalytic converters have much stricter limits than older vehicles. The DVSA new MOT rules, including those for electric vehicles, are continually updated. While electric vehicles do not have exhaust emissions, their MOT still covers safety aspects like brakes, tyres, lights, and structural integrity.
Regular maintenance, including servicing your exhaust and ensuring your engine is running efficiently, can help prevent an emissions-related MOT failure. If your car has been running poorly or making unusual noises from the exhaust, it's wise to have it checked before the MOT.
Ensuring your exhaust system is sound and your engine is well-maintained is key to passing the emissions part of the MOT.
Other Critical MOT Failure Points
Beyond the most common issues, several other areas can cause your vehicle to fail its MOT. The steering and suspension systems are checked for excessive wear or looseness. Components like ball joints, track rod ends, and bushings must be in good condition. If there's too much play in any of these parts, it's a fail.
The vehicle's body and chassis are inspected for structural integrity. This includes checking for excessive corrosion that could compromise safety. Areas like wheel arches, sills, and the floor pan are examined. Any sharp edges protruding from the bodywork that could injure pedestrians are also a fail.
Horn and Registration Plates
The horn must be present and audible. If it's not working or is a non-standard, excessively loud type, it can result in a fail. Registration plates are checked for legibility, security, and correct format. Missing, faded, or incorrectly displayed plates will cause a failure.
For electric vans, the uk electric van MOT rules change starting on june 1 apply, focusing on the safety of high-voltage systems, battery condition, and charging points, in addition to standard roadworthiness checks. This reflects the evolving automotive landscape and the need to adapt safety standards.
Always check official DVSA guidance for the most up-to-date and comprehensive list of MOT failure points.
Before your MOT, check your lights, tyres (pressure and tread depth), windscreen wipers, and horn to catch obvious faults and avoid an immediate fail.
What Happens After a Failed MOT?
If your vehicle fails its MOT, you’ll receive a report listing the defects. You cannot drive the vehicle until these defects are repaired, unless you are taking it to a pre-arranged repair appointment or retest. The vehicle must be repaired to meet the required standards. It's crucial to address all 'Dangerous' and 'Major' defects identified.
Once repairs are completed, your vehicle will need a retest. Depending on the centre and the extent of the repairs, some centres offer a partial retest on specific items, while others may require a full MOT again. It is often beneficial to have the repairs carried out at the same garage that performed the original MOT, as they may offer a free or reduced-price retest if the vehicle is brought back within a certain timeframe, typically 10 working days.
However, if you choose to take your vehicle to a different garage for repairs, you will typically have to pay for a full MOT test again. Always clarify the retest policy with the MOT centre when you book your initial test. This understanding can save you money and hassle.
To avoid unexpected costs and inconvenience, it is always advisable to perform pre-MOT checks yourself. This includes inspecting tyre tread depth and condition, checking all lights are working, ensuring the windscreen is clear and free from significant chips, and verifying that your horn functions correctly. By proactively checking these common mot tyre rules and other critical areas, you significantly increase the chances of passing first time.