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What Warning Lights Can Lead To MOT Failure

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  • 15-08-2023
What Warning Lights Can Lead To MOT Failure

What warning lights can lead to MOT failure? From engine management to airbags, understand how these indicators impact your vehicle's roadworthiness. Godstone Mercedes Ltd offer Mercedes servicing & MOT in Godstone and Surrey. Learn about the potential issues behind warning lights and ensure your car is in top condition for a successful MOT.

Warning Lights to Check Before an MOT Test

When it comes to the MOT test, a dashboard filled with illuminated warning lights can be a cause for concern. These warning lights serve as essential indicators, alerting you to potential issues with your vehicle. However, having certain warning lights illuminated during the MOT test can lead to an automatic fail.

Therefore, understanding the significance of these warning lights and taking timely action is crucial to ensure your car's success in passing the MOT examination. Some warning lights hold particular importance in determining the outcome of the MOT test. 

What Stops A Car From Passing An MOT?

The ABS light, engine management light, brake fluid light, and airbag warning light are among the most critical indicators. Should these warning lights be illuminated during the test, it is highly likely that your car will fail the examination.

These lights directly relate to vital safety systems and overall vehicle performance, and any issues with them need to be addressed promptly. While not all engine warning lights will result in an MOT failure, it is essential to approach any illuminated warning light with caution. 

Often, these warning lights signify underlying problems that require attention. Ignoring warning lights can exacerbate issues and lead to more extensive and costly repairs in the future.

Thus, it is best practice to take any warning light seriously and seek professional assistance to diagnose and resolve the problem before the MOT test. To increase the chances of your car passing the MOT test with flying colours, it is vital to ensure that all warning lights on your dashboard are thoroughly checked and resolved ahead of time. 

Regular vehicle maintenance and proactive repairs can significantly reduce the likelihood of encountering warning lights during the MOT examination, providing you with peace of mind and confidence in your vehicle's roadworthiness.

What do car dashboard warning lights mean?

Car dashboard warning lights play a vital role in keeping you informed about your vehicle's health and safety. When a warning light illuminates on your dashboard, it serves as a crucial indicator that the condition of your car has changed and requires attention.

These warning lights act as a proactive communication system, helping you address potential issues that may impact your car's performance and safety while driving. Warning lights can take the form of symbols or words, visually representing the specific problem that needs addressing.

What Warning Lights Can Lead To Mot Failure?

In some vehicles with digital driver's displays, additional text may accompany the warning light, providing further explanation of the issue at hand. This clear visual and textual feedback empowers drivers to respond promptly to any emerging problems.

While certain warning lights are standard and present in every car, others may pertain to specific equipment that only certain vehicles possess. Despite slight variations in symbols across manufacturers, the meaning behind the warning lights remains consistent. Understanding these indicators is essential for every car owner to ensure safe and responsible driving.

Some warning lights highlight relatively simple issues that may not hinder immediate driving. However, others may signal critical problems that demand immediate attention to maintain safe vehicle operation. Ignoring warning lights can lead to potential hazards on the road and result in more significant and expensive repairs down the line.

Most Common Warning Lights

Your car's dashboard warning lights serve as crucial communication tools, alerting you to potential issues that require attention. Understanding the meaning of these warning lights is essential for every car owner to ensure safety and prevent potential breakdowns.

In this comprehensive guide, we will explore the most frequently encountered warning lights and provide insights on how to respond effectively.

 Low Tyre Pressure Warning

This warning light indicates that your tyre pressures have dropped below a safe level. It could be a result of neglecting to pump them up or possibly due to a puncture.

When this warning appears, it is vital not to exceed 50mph and promptly find a fuel station to inflate the tyres to the recommended pressure.

After doing so, you need to reset your car's tyre pressure monitoring system (TPMS) to clear the warning. Always take this warning seriously and ensure that your tyres are properly inflated for safe driving.

Most Common Warning Lights

 Low Battery Charge Warning

When you start your car and see the low battery charge warning, it indicates that your car's battery is not fully charged. This warning is most likely due to an ageing battery that needs replacement.

In some cases, it could be a sign of a faulty alternator that fails to charge the battery adequately. If the warning light appears while driving, find a safe spot to stop and call a breakdown service for assistance, especially during night time when the headlights may go out, and the engine could stall.

 ABS Failure Warning

The anti-lock braking system (ABS) is a critical safety feature in modern cars, preventing skidding during heavy braking. If the ABS failure warning light comes on, it typically indicates a failed sensor within the ABS system. While the brakes will still work, they may not function as effectively.

If the ABS failure warning appears while driving, stop your car in a safe place and contact a breakdown service for further inspection. When braking with the ABS warning light illuminated, be cautious, as the tyres may skid.

 Engine Temperature Warning Light

The engine temperature warning light signifies that your car's engine is overheating and is at risk of breaking down. The most common reasons for this warning are low engine oil or low coolant levels.

If the warning light appears, you can address the issue by refilling the engine oil or coolant yourself. However, if the warning light repeats or persists, it may indicate a more serious problem that requires professional attention.

If the engine temperature warning light illuminates while driving, it is crucial to stop in a safe location immediately and seek assistance from a breakdown service. Continuing to drive with an overheated engine can lead to severe damage and costly repairs.

Engine Temperature Warning Light

 Engine Management Warning

The engine management warning light signifies that the engine management system, also known as the electronic control unit, has detected a fault that could affect the engine's performance. 

The list of potential causes is extensive, ranging from blocked filters to electrical faults. If the engine management warning light appears while driving, it is likely that the engine will go into a low-power 'limp' mode, restricting acceleration and top speed. 

The severity of the problem will dictate how slow your car becomes. If it's safe to continue driving, head to the nearest garage for repairs. 

However, if the issue poses a significant risk, stop in a secure location and call a breakdown service for assistance.

Understanding the meaning of common warning lights is a fundamental aspect of responsible car ownership. These warning lights serve as your car's early warning system, informing you of potential issues that require attention. Taking prompt action and maintaining your vehicle regularly can prevent breakdowns, enhance safety, and prolong the life of your car.

By staying informed and proactive, you can confidently navigate the road and enjoy a smooth and worry-free driving experience. Remember, safety should always be a top priority when it comes to your vehicle, and being attentive to warning lights is a key step in ensuring your car's optimal performance and peace of mind on the road.


Are you looking for Mercedes MOT in Surrey? If you are a Mercedes-Benz owner you will want to ensure your car is in the right hands. 

 Follow the links below for Mercedes servicing and repairs in Godstone, Crawley, Croydon, Sevenoaks and the surrounding areas.