Engine management light

Why is my engine management light on?

What you should do if your engine warning light comes on

Has your vehicle’s engine management light (EML) turned on? It normally takes the form of an engine block or “check engine” wording and appears on the dashboard behind your steering wheel.

A dashboard warning light can often be one of the first signs of a problem with your vehicle. The EML is generally triggered when your car’s sensors detect a potential issue with the engine.

But how do you know exactly what’s causing the EML to come on and what can you do about it?

Below, we outline some of the causes of the engine management light and what you can do to resolve the issue and continue driving safely.

Read our complete guide to dashboard warning lights and what they mean.

In this article

Engine management light lit up on car dashboard

What does the engine management light mean?

The EML or check engine light is a bit different to other dashboard warning lights. This is because it doesn’t alert you to a specific fault.

A flashing or continuous EML lets you know there might be a problem with the engine. There are a number of reasons that can cause this, ranging from minor issues to much more serious ones.

Cars have sensors to check everything is running smoothly – if an issue is found relating to exhaust emissions, the sensor will tell the engine control unit (ECU) which turns on the EML. A broken sensor can also turn on the EML.

Is it safe to drive with the engine management light on?

Generally, unless there are other symptoms that’s something’s wrong, you can continue driving to your destination. Have your vehicle looked at by an expert as soon as possible to avoid risking further damage to your car.

But if you experience other issues with your vehicle that suggests something’s wrong with the engine, or the EML is red or flashing while the engine is on, this could indicate a more serious problem. If this happens, you should:

  1. Pull over as soon as it’s safe to do so.
  2. Switch off the engine.
  3. Contact us to report your breakdown so one of our patrols can help diagnose and resolve the problem.

We provide 24/7 roadside assistance.

Which types of engine management light are there?

Your engine management light can tell you there’s a problem in three different ways:

  • Steady amber light

A steady amber engine management light represents a less serious issue, usually to do with emissions. You’ll likely be able to finish your journey but it’s best to get your car checked as soon as possible.

  • Flashing amber light

A flashing amber light is a more serious issue than a steady amber light, and could mean there’s a critical problem with the catalytic converter (along with a number of other issues). Without immediate action you could face a seriously costly repair, so make sure to have your car checked by a mechanic immediately.

  • Steady red light

A red engine management light represents a critical issue with your car. If you see this light turn on, stop driving and call your breakdown cover provider immediately.

Is the engine warning light serious?

If you get a flashing amber or red engine management light, then yes, it could be a serious problem which means you need to get your vehicle checked over and fixed by a mechanic immediately. 

How do I fix a car engine management light?

There are several problems that may cause an EML to switch on and diagnostic equipment is required to find it. You’ll need to get a mechanic to find and fix the issue so you should take it to a garage as soon as possible.

But if you’re experiencing other issues with your vehicle that indicate an engine problem, or the EML is red or flashing while driving, this suggests a more serious fault so you should stop driving as soon as it’s safe to do so and contact us to report your breakdown.

Why is the engine management light flashing/illuminated?

There are many reasons for an illuminated engine management light. Some of the most common are listed below.

1. Oxygen sensor malfunction

If the sensor detects issues that your vehicle’s fuel is too rich (not enough air) or too lean (too much air, the EML might turn on.

It may also be illuminated if there's a fault with the sensor.

2. Blocked diesel particulate filter

The diesel particulate filter (DPF) captures and stores exhaust soot to help your engine pollute less.

If there’s a fault with it or the differential pressure sensor, which lets your car know the status of the DPF, the EML light might come on.

3. Mass airflow sensor

The ECU relies on the mass airflow sensor to work out how much fuel to add to the combustion chambers to correlate the amount of air coming into the engine.

If the air filter is missing, damaged or blocked, this can cause the EML to come on.

4. Ignition system fault

If you have a petrol car, problems with your spark plugs or coils may cause the EML to start flashing.

5. Loose oil dipstick

If the EML turns on shortly after you’ve checked the oil in your car, it could be due to the dipstick being loose. Make sure the dipstick has been put back properly and see if that resolves the issue.

Can low oil cause the engine management light to come on?

If your car's low on oil, this is a serious issue that should be resolved as soon as possible. But it very rarely results in the EML switching on.

Low oil has its own dashboard warning light (it usually looks like an oil can) that should alert you to this issue.

Find out how to check and top up your oil.

We'll help you get back on the road.

Will a car’s engine management light reset itself?

No, if the EML comes on in your car, you’ll need to take it to a garage so that a mechanic can diagnose and fix the fault. After the issue has been resolved, the light will turn off automatically.

If the EML turns on again, after the problem is fixed, you should take your car back to the garage.

You might find that when the EML first turns on, it turns off again after a short while. If it turns off and on intermittently, this is due to the fault only being detected by the sensor at certain times. You should take your car to a garage to resolve the issue and stop the EML turning back on.

Does an engine management light fail an MOT?

An amber or red EML that stays on when the engine has been started is classed as a major fault. This means it will cause your vehicle to fail its MOT test.

Use our MOT checklist to help pass your next MOT test.


Why is the engine management light on?

The engine management light only turns on to warn you of an issue with your car, flashing amber or red engine management lights reflect more serious issues that you should try to remedy as soon as possible. The EML turning on can indicate issues with the oxygen sensor, diesel particulate filter, mass airflow sensor, ignition system or a loose oil dipstick etc.

How to reset the engine management light?

If the engine management light comes on in your car try parking somewhere safe and restarting the engine after 2 minutes. If the light is still on then the only guaranteed way to make sure your engine management light resets and turns off is to take it to a mechanic to get the issue fixed. If you try to reset it another way then you may be ignoring a potentially critical issue with your car.

Why is the engine management light flashing?

The engine management light will only flash if there’s a potentially serious issue with your car, such as a misfire. A flashing amber light is worse than a steady amber engine management light, so make sure to take your car to a mechanic immediately.

How long can you drive with the engine management light on?

You’ll normally be able to drive for a while after the engine light comes on (as long as it’s not flashing), but try to avoid heavy acceleration and high engine speed. It’s not advisable to drive more than another couple of miles without getting your car checked by a professional mechanic.

Is the engine warning light serious?

Engine warning lights can display varying grades of seriousness. A red or flashing amber engine management light represents a more serious issue than a steady amber light.

More on car issues:

Published: 8 December 2021 | Updated: 24 July 2023 | Author: The AA

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