When it comes to vehicle safety and roadworthiness, few things are as crucial as the annual MOT test in the UK. One of the most common concerns for vehicle owners is the impact of dashboard warning lights on their MOT results. This comprehensive guide will explore which warning lights can lead to an MOT failure and how to address these issues to ensure your vehicle passes with flying colors.
| Warning Light | MOT Impact | Severity |
|---|---|---|
| Engine Management Light | Fail | High |
| ABS Light | Fail | High |
| Airbag Warning Light | Fail | High |
| Brake System Warning | Fail | High |
| Tyre Pressure Monitoring System | Fail (for vehicles from 2012) | Medium |
Understanding MOT and Warning Lights
The MOT (Ministry of Transport) test is an annual check of vehicle safety, roadworthiness aspects, and exhaust emissions required in the United Kingdom for most vehicles over three years old. One of the critical areas inspected during an MOT test is the dashboard warning lights.
Warning lights are designed to alert drivers to potential issues with their vehicle's systems. These lights can indicate problems ranging from minor concerns to severe safety hazards. Understanding which warning lights can lead to an MOT failure is crucial for vehicle owners to ensure their cars pass the test and remain safe on the roads.
The Significance of Warning Lights in MOT Tests
MOT testers are required to check that certain warning lights illuminate when the ignition is switched on and then extinguish once the engine is running. This check ensures that the warning light systems are functioning correctly and can alert the driver to potential issues while driving.
"As a general rule, a warning light in the instrument display will be a fail point if it indicates the failure of a component that is also part of the test procedure."[24]
This statement underscores the importance of addressing any illuminated warning lights before your MOT test. Let's delve deeper into the specific warning lights that can lead to an MOT failure.
Warning Lights That Will Fail Your MOT
1. Engine Management Light (EML)
The Engine Management Light, often referred to as the "Check Engine" light, is one of the most critical warning indicators on your dashboard. If this light remains illuminated during your MOT test, it will result in an automatic failure.
An illuminated EML can indicate various issues, from minor sensor malfunctions to severe engine problems. The MOT tester cannot determine the exact cause without further diagnostics, but the presence of this warning light suggests that the vehicle's emissions may exceed legal limits or that there's a significant issue with the engine's performance.
Action required: If your EML is on, it's crucial to have your vehicle diagnosed and repaired before the MOT test. Many auto parts stores offer free diagnostic scans that can help identify the issue.
2. ABS (Anti-lock Braking System) Warning Light
The ABS warning light indicates a problem with the vehicle's anti-lock braking system. This safety feature is critical for maintaining control during emergency braking situations.
An illuminated ABS light will result in an immediate MOT failure. The ABS system is considered a crucial safety feature, and any malfunction could compromise the vehicle's ability to stop safely.
Action required: If your ABS light is on, have the system checked by a qualified mechanic. Common issues include faulty wheel speed sensors or ABS control module problems.
3. Airbag Warning Light
The airbag warning light indicates a problem with the vehicle's Supplemental Restraint System (SRS). This system is responsible for deploying airbags in the event of a collision.
An illuminated airbag warning light will cause your vehicle to fail its MOT test. The airbag system is a critical safety feature, and any malfunction could put occupants at risk in the event of an accident.
Action required: If your airbag light is on, have the SRS system diagnosed by a professional. Common issues include faulty sensors or expired airbag modules.
4. Brake System Warning Light
The brake system warning light can indicate various issues, from low brake fluid levels to more severe problems with the braking system.
An illuminated brake warning light will result in an MOT failure. The braking system is fundamental to vehicle safety, and any issues must be addressed immediately.
Action required: Check your brake fluid levels first. If they're low, top them up and see if the light goes out. If the light remains on, have your braking system inspected by a professional mechanic.
5. Tyre Pressure Monitoring System (TPMS) Warning Light
For vehicles first used after 1 January 2012, the Tyre Pressure Monitoring System is part of the MOT test. This system alerts drivers when tyre pressure is too low or too high.
An illuminated TPMS warning light will result in an MOT failure for applicable vehicles.
Action required: Check and adjust your tyre pressures according to the manufacturer's recommendations. If the light remains on, you may need to have the TPMS sensors checked or reset.
Other Warning Lights to Be Aware Of
While not all warning lights will result in an automatic MOT failure, it's important to address any illuminated warnings before your test. Some lights that may not directly cause a failure but could indicate underlying issues include:
- Power Steering Warning Light
- Battery Charge Warning Light
- Oil Pressure Warning Light
- Coolant Temperature Warning Light
These lights may not cause an immediate fail, but they could indicate problems that might affect other aspects of the MOT test, such as emissions or vehicle safety.
Preparing Your Vehicle for the MOT Test
To increase your chances of passing the MOT test and avoiding issues with warning lights, follow these steps:
- Regular Maintenance: Keep up with your vehicle's regular service schedule. This can prevent many issues that trigger warning lights.
- Pre-MOT Check: Conduct a thorough check of your vehicle about a month before your MOT is due. This gives you time to address any issues.
- Address Warning Lights Promptly: If any warning lights appear on your dashboard, have them diagnosed and repaired as soon as possible.
- Check All Lights: Ensure all external lights are working correctly, including headlights, taillights, indicators, and brake lights.
- Tyre Inspection: Check tyre tread depth and pressure, ensuring they meet legal requirements.
What to Do If Your Vehicle Fails the MOT Due to Warning Lights
If your vehicle fails its MOT due to warning lights, don't panic. Here's what you should do:
- Understand the Failure: The MOT tester will provide a list of reasons for the failure. Make sure you understand what each issue means.
- Get a Professional Diagnosis: Have a qualified mechanic diagnose the exact cause of the warning light.
- Repair the Issues: Once diagnosed, have the necessary repairs carried out.
- Retest: After repairs, you can have your vehicle retested. If this is done within 10 working days, you may be eligible for a partial retest, which could be free or at a reduced cost.
The Importance of Addressing Warning Lights
While preparing for an MOT test is important, it's crucial to remember that warning lights serve a vital purpose beyond just passing a yearly inspection. They are your vehicle's way of communicating potential issues that could affect its safety, performance, and longevity.
Addressing warning lights promptly can:
- Prevent minor issues from becoming major, expensive repairs
- Ensure your vehicle remains safe to drive
- Maintain your vehicle's performance and fuel efficiency
- Potentially increase your vehicle's lifespan
"Warning lights usually indicate a problem that will impact the performance of the vehicle, so the car will likely fail its MOT test."[22]
This statement emphasizes the dual importance of addressing warning lights: not only for passing your MOT but for maintaining your vehicle's overall health and safety.
The Future of MOT Tests and Warning Lights
As vehicles become more technologically advanced, the role of warning lights in MOT tests is likely to evolve. We may see more sophisticated diagnostic procedures becoming part of the standard MOT test, potentially including:
- More comprehensive electronic system checks
- Integration of onboard diagnostic (OBD) systems into the MOT process
- Checks for advanced driver assistance systems (ADAS)
Staying informed about these changes and maintaining your vehicle accordingly will be crucial for future MOT success.
Conclusion
Understanding which warning lights can fail your MOT test is crucial for every vehicle owner in the UK. The most critical lights to be aware of are the Engine Management Light, ABS Warning Light, Airbag Warning Light, and Brake System Warning Light. These lights indicate issues that directly impact your vehicle's safety and emissions, which are core aspects of the MOT test.
Regular maintenance, prompt attention to any illuminated warning lights, and thorough preparation before your MOT test can significantly increase your chances of passing. Remember, while passing the MOT is important, the ultimate goal is to ensure your vehicle is safe and roadworthy at all times.
By staying informed and proactive about your vehicle's health, you not only increase your chances of MOT success but also contribute to safer roads for everyone. Don't ignore those dashboard warnings – they're there to help you maintain a safe, efficient, and legal vehicle.
FAQs
- Can I still drive my car if it fails the MOT due to a warning light?
No, it's illegal and unsafe to drive a car that has failed its MOT, except to a pre-booked repair appointment or another MOT test. - How long do I have to fix issues after failing an MOT?
You have 10 working days to have your vehicle repaired and retested for a reduced fee or potentially free partial retest. - Will disconnecting the battery reset warning lights for the MOT?
No, this is not recommended and could be detected, potentially leading to test failure or even accusations of fraud. - Are all dashboard warning lights checked during an MOT?
Not all, but critical safety-related lights like ABS, airbags, and engine management are always checked. - Can I pass an MOT with the check engine light on?
No, an illuminated check engine light (EML) will result in an automatic MOT failure.
