Have you noticed an illuminated engine management light (EML) on your car’s dashboard?

A lit up dashboard warning light can be a source of anxiety, but your vehicle’s engine management light is there to give you a chance to fix potential issues with your car.

An illuminated EML can lead to MOT failure if you don’t have the problem sorted as this is considered to be a major fault.

That's why it is so important that you book a diagnostic check as soon as you notice this warning light.

Read on and find out 5 reasons why your car’s engine management light might have come on, what this means, and how to reset it.


What Does My Engine Management Light Look Like?

The engine management light looks like the outline of an engine.

An amber engine management light.

Don't ignore an illuminated check engine light for long.

This warning light can also show as the words 'check engine'.


What Can Cause the Engine Management Light to Come On?

The engine management light – also known as the ‘check engine’ light - can come on for a wide range of reasons, so it isn’t always easy to identify the exact cause of the problem.

Many issues can be difficult to find without specialist equipment and an expert knowledge of engine fault codes, which is why you should book a diagnostic check if you notice this warning light.


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A professional mechanic will be able to identify the issue and reset the engine management light for you.

Whilst it can be difficult to determine the exact cause without the help of a mechanic, here are some of the most likely reasons why your EML is illuminated.


Blocked Diesel Particulate Filter (DPF)

Whilst modern diesel cars are likely to have a diesel particulate filter (DPF) warning light, the EML is likely to come on too if the filter becomes blocked.

If the DPF does not regenerate when it needs to – be it active or passive regeneration – then you may need to book in with a professional mechanic.

You may wish to book a DPF clean if the problem is not too severe.


Ignition System Fault

In a petrol car, the engine management light can start flashing if there is a problem with the spark plugs or coils.

Petrol-powered cars rely on the ignition system to run the engine, and the car can misfire and lose performance if there is an ignition system fault.

If the spark plugs or coils get old or develop a fault, they will struggle to provide the spark that helps fuel and air combust within the engine.

This can make it hard to start the vehicle and will cause a jerky drive or occasional dips in power whilst driving.


Contaminated Catalytic Converter

You should have a contaminated catalytic converter looked at immediately.

The catalytic converter keeps exhaust emissions as clean as possible.

Any issue or damage can lead to a very expensive repair if left to deteriorate.


Oxygen Sensor Malfunction

Modern cars have sensors in their exhaust systems to monitor the oxygen content of exhaust fumes. These ensure that your car is as efficient and environmentally friendly as possible.

If too much or too little oxygen leaves your car, or there is a fault with the sensor, the check engine light will come on.

Not enough oxygen indicates that your fuel is burning too rich, whilst too much indicates that your fuel is running too lean.


Mass Airflow Sensor Fault

A mass airflow sensor fault can signal that your air filter could be missing, damaged or blocked.

Without the data from this sensor, your ECU will assume that the engine is getting no air at all and will trigger the EML.

This will protect the engine from overheating and causing serious damage.

You may experience rough idling or jerky acceleration if the engine isn’t burning enough oxygen during combustion.

Your car’s air filter should be changed every couple of years.

In addition, the issue causing the EML to come on could be any of the following:

  • Faulty Exhaust Gas Recirculation Valve (EGR)
  • Leaky Vacuum Hose
  • Blocked Fuel Injectors
  • Blocked Fuel Pump
  • Loose Filler Cap

You should drive at a reduced speed to the nearest garage if you experience any of these issues whilst driving.


How Do I Reset My Check Engine Light?

Your car’s check engine light will not reset itself – you need to take it to a garage so that a mechanic can diagnose and fix the fault for you.

Once the issue is resolved, the light should turn off automatically. If the light turns back on after the problem is fixed, then you will need to take it back to the garage.


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You can book a diagnostic check so that a technician can use state-of-the-art equipment to scan your ECU and find out which error code(s) it is reporting.

Once the technician knows what’s wrong with your vehicle, they will provide you with a quote for the repair and get your car back on the road as quickly as possible.


Why Should I Do Something About My Check Engine Light?

If your car is struggling to run efficiently, this can put additional strain on other related car parts.

Ignoring a check engine light could result in a costly repair later down the line as a result of increase wear and tear.

You may notice a decrease in fuel economy, as your engine will have to work harder keep you moving – meaning higher fuel bills and more regular fill ups.

Not to mention that an illuminated engine management light could mean your vehicle fails its MOT if you don’t have the problem resolved and the light reset soon.


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What Does the Engine Management Light Mean?

Modern cars feature multiple on-board sensors which monitor the performance of the engine and other systems.

Measuring aspects such as the amount of air drawn into the system, the type of emissions produced, and how well the engine is igniting the fuel, a car’s on-board computer can report on how effectively the vehicle is running.

The engine management light doesn't indicate a specific fault – unlike other warning lights – but it can alert you that there is an issue with your vehicle.

The EML could be alerting you to more than one issue, usually relating to the engine or exhaust emissions.

Some are far more serious than others, depending on the type of light that is illuminated.


Steady Amber Engine Management Light

A steady amber engine management light usually indicates that there is an issue with emissions, and is the least severe type of check engine light you may see.

You should be able to finish your journey, but you should have your vehicle looked at by a professional mechanic soon.


Flashing Amber Engine Management Light

A flashing amber EML is more serious than a steady amber light, and could indicate that there is a critical problem with the catalytic converter or another vital component.

You must act quickly and book in with a professional mechanic now to avoid a costly repair later down the line.


Steady Red Engine Management Light

A steady red engine management light means that there is a critical issue with your car.

You should stop driving if you see this light and call your breakdown cover provider right away.


Is It Safe to Drive with the EML On?

Whilst you can continue driving your vehicle with the EML on – provided there are no signs that something is wrong with your car – you should have it looked at as soon as possible.

You should not keep driving the vehicle if the EML is red or flashing whilst the engine is on, as there could be a more serious problem with your car.

If you notice this whilst driving, you should pull over when it is safe to do so, turn off the engine, and call your breakdown cover provider to assist you.

Continuing to drive the vehicle could do further damage to your car’s vital components.


Can I Keep Driving If I Lose Power?

Modern cars have engine control units (ECU) that will automatically put the car into ‘limp home’ mode when a problem is detected.

Power will be restricted in an effort to keep driving safe and reduce the likelihood of an accident.

You should not continue driving your car if you can help it, especially if you notice any of the following:

  • Sluggish acceleration
  • Top speed between 35 and 45mph
  • RPM limited to less than 3,000
  • EML is on

Limp home mode is usually activated when a serious problem is detected, so you should never ignore it.

Driving for an extended period of time in limp home mode will only exacerbate the problem.

If your vehicle enters limp home mode and you are far away from your destination or need to join fast roads, then you may need to have it rescued.


You should book a diagnostic check as soon as possible to have the problems affecting your vehicle fixed.


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We hope you have enjoyed learning all about your vehicle's engine management light.



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