A lit up engine management light (EML) on your vehicle's dashboard means that your car's on-board sensors have detected a problem.
Ignoring a check engine light could result in a costly repair later down the line as a result of increased wear and tear.
An illuminated EML light can also result in MOT failure if you don’t have the problem fixed.
You will need to take the vehicle to a garage to have the engine management light reset and the related issue resolved.
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What Is the Meaning of the Engine Management Light?
The engine management light - also known as the check engine light - in your car is an engine-shaped symbol on your car's dashboard.
It is triggered by the onboard computer system if an engine-related issue is detected.
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 usually lights up when you start the vehicle and should switch off after a few seconds.
If the light stays on or starts flashing, then that means that there could be a problem with the engine or another related issue to address.
Some EML problems are far more serious than others, as indicated by the type of light that is illuminated.
Steady Amber Engine Management Light
A steady amber engine management light - which could look yellow or orange - usually indicates that there is an issue with emissions.
This is the least severe type of check engine light you may see.
If a yellow engine management light comes on, you should be able to finish your journey - provided the vehicle isn't experiencing a lack of power.
Even so, you should book a diagnostic check with a mechanic as soon as you reach your destination.
Flashing Amber Engine Management Light
A flashing amber EML is more serious than a steady amber light.
This type of engine management light means that there may be a critical problem with the catalytic converter or another vital component.
You should stop driving right away and contact a mechanic.
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 a red engine management light and call your breakdown cover provider right away.
What Can Cause the Engine Management Light to Come On?
The engine management light can come on for a wide range of reasons, and it can be a source of anxiety when it does.
However, your vehicle’s engine management light is actually there to give you a chance to fix potential issues with your car.
Whilst it can be difficult to determine the exact cause without a mechanic, here are some of the most likely reasons why your car's EML is illuminated:
- A blocked DPF
- An ignition system fault
- A contaminated catalytic converter
- An oxygen sensor malfunction
- A mass airflow sensor fault
Blocked Diesel Particulate Filter (DPF)
Most modern diesel cars have a diesel particulate filter (DPF) warning light.
When the filter becomes blocked, the EML is likely to come on, too.
If the DPF does not regenerate when it needs to – be this 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 to try and prevent the diesel particulate filter from becoming blocked.
Ignition System Fault
In a petrol car, a flashing engine management light can indicate there's 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.
If the catalytic converter fails, then this can cause the EML on your car to come on.
Not to mention that 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 engine control unit (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.
What to Do When the Engine Management Light Comes On
If the EML comes on, the issue needs to diagnosed and fixed by a professional mechanic during a diagnostic check.
It's especially important that you book a diagnostic check if the EML is flashing or has been on for a while.
Any changes in your vehicle's performance can also indicate that a diagnostic check is required.
Even if the light isn't red, it is a good idea to stop driving until you've had the car checked by a mechanic.
If the check engine light is red, do not drive until the problem is fixed - you should pull over and call your breakdown cover provider if you are driving when this light comes on.
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 EML 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.
