Will My Car Fail its MOT Test if the Engine Management Light is On?

Your car may fail its MOT if there are issues with the suspension or brakes, but what about the engine management light? 

The EML comes on to let you know when there’s an issue with the engine, exhaust or emissions system. 

If your car’s EML is on, it means something is wrong with your car – so you may be concerned about passing an upcoming MOT test. 

In this blog, we cover whether the EML being on means MOT failure, what causes this light to come on, and how to turn it off... 

Is an Illuminated EML Cause for an MOT Fail?

Yes, if your car has an illuminated engine management light that stays on during an MOT test, this will be classed as a major fault, and your car will fail the test. 

This is understandable, given that this likely means an aspect of your car is not as safe or working as well as it needs to be. 

If you notice that your car’s EML stays on when you turn on the ignition or it comes on when driving, then there could be a problem under the bonnet which a garage needs to fix for you. 

That’s why it pays to be prepared and have any issues fixed ahead of your MOT test, to give your car the best chance of passing. 

When you book a professional diagnostic check, a mechanic will use the necessary tools and equipment to pinpoint the underlying issue and find a solution for your car.

Common Causes of an Illuminated EML

Your car’s engine management light can come on for a range of reasons, including any of the following: 

• Engine overheating 
• Software issues 
• A loose or damaged fuel cap 
• Catalytic converter problems 
• Performance issues 

Unlike other warning lights, the EML doesn’t indicate a specific fault, but can let you know that a problem is present.

What Do the Different EML Colours Mean?

The engine management light will show as a steady amber, red or flashing light, depending on the severity of the underlying issue. 

Whilst you may be fine to keep driving your car with an amber EML, a flashing or red light can be more serious and mean that there is a problem impacting the way your car handles or drives. 

If you notice a red light whilst driving, you should pull over when it is safe to do so, and call a breakdown provider right away.

How Do I Turn Off My Car's EML?

Once the issue with your car has been sorted, the technician working on your vehicle will then reset the ECU – this should turn off the EML after a little while. 

If the light comes back on after the repair – or doesn’t go off – then this could mean that there are still issues with your car which need to be addressed. 

The garage may need to perform another reset of the EML – the light should not be coming on for no reason at all.

We're here to help you find a local garage to carry out your diagnostic check, giving you the peace of mind and confidence in your vehicle you deserve.

Is your car ready to take the MOT test? You can choose from a range of professional local garages to find the right one to carry out your vehicle’s inspection.