Please note:
- Before you work on your vehicle or disconnect the battery, please refer to your vehicle handbook for guidance first.
- You should always check your vehicle handbook for any fault remedy before carrying out any work on your vehicle. If you are unsure of what is required to fix any problems, please consult a professional.
- If you see a red engine management light, it means your engine has a serious fault and you should pull over and seek roadside assistance.
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What is an Engine Management Light (eml light)?
The engine management light is one of your vehicle’s dashboard warning lights.
The check engine light lets you know there might be an issue with the engine.
Why does my EML check engine light come on when I start my car?
It is normal for the engine management light to illuminate with the ignition prior to starting, however, it should always go out once the car is running.
What does it mean if a check engine warning light stays on?
If the engine management warning light remains on continuously, or the engine management light is flashing after the ignition has started, then you may have a problem.
Unlike other dashboard warning lights, the check engine light doesn’t alert you to a specific fault so it’s best to get your car checked over for any issues as soon as possible.
What does the Engine Management Light look like?
The EML light usually displays as an engine block or, in some vehicles, as “check engine” wording and appears on the dashboard behind your steering wheel.
Some cars display the engine warning light in different colours according to how serious the problem is.
As mentioned above, the engine warning light may also flash.
Check your vehicle handbook for the precise definitions but typically, the check engine light (EML) will appear on your dashboard as a red or amber light.
What can cause the check engine warning light (EML light) to come on?
You may be wondering what can cause the check engine management light to come on but the check engine warning light, or engine management light (eml) as it is properly named, can appear for a number of issues.
Ensuring that you have appropriate breakdown cover in place can offer you peace of mind, should you experience an issue with the eml coming on on your dashboard.
Red engine management light
A red EML light indicates that there is a serious problem with your vehicle.
Can I continue to drive my vehicle if a red EML is lit?
With a red engine management warning light, you should pull over where it's safe to do so and arrange for your car to be recovered.
Driving further with a red check engine light displaying could potentially cause expensive damage.
Amber engine management light
If your dashboard is displaying or flashing the amber engine management light symbol, your powertrain may have a problem.
This error may be caused by something simple, or it could be a more serious issue.
It's important to find out what the problem is and fix it.
Can I continue to drive my vehicle if an amber engine warning light is lit?
An amber engine light doesn't necessarily point to an unfolding emergency.
Unless there are other symptoms that there is something wrong with your car, you should be able to continue your journey and seek advice upon reaching your destination.
After the amber engine warning light issue is solved
Once you have solved the issue, you may find that the amber engine management light remains on due to a glitch. In this case, there are a few easy ways to make the light switch off.
We’ll explain how to complete an engine management light reset below.
We’ll also show you how to determine the cause of any fault.
Finding out what the fault is:
On-board diagnostic scanner
The easiest way to determine a fault causing the amber engine management light to come on is to use an OBD2 (on-board diagnostic) scanner.
This device can be purchased online for around £20.
Simply connect the OBD2 scanner to the connection port, which should be located under your dashboard on the passenger side. Almost all cars built after 2000 have this port.
How to use an on-board diagnostic scanner
After connecting the OBD2, turn off all connected gadgets then turn on your ignition.
Press the "READ" button and any error codes will be displayed.
Note down the codes then consult your car's handbook to find out what the fault is. If you don’t have your handbook, the manual that came with the scanner should tell you what the code(s) mean.
Next, press "ERASE" (or "CLEAR" on some scanners), which will clear all the error codes. If all the error codes are cleared, the amber engine management light will go off.
What if you don't have an on-board diagnostic scanner?
Alternatively, you may decide to take your vehicle to your local garage, where they will have an OBD2 diagnostics scanner. They will then scan the code and determine the issue with your EML.
Resetting the engine management light:
How to reset engine management light: How to turn off the engine warning light?
If you believe there are no issues with your engine, but the check engine light remains on, there are a number of ways for how to turn off the engine management light.
One of the best known methods to reset the engine management light is to disconnect your car's battery cables.
How to reset engine management light by removing car battery cables
- Use a wrench to remove positive and negative cables.
- Next, drain any residual current by holding down the horn for half a minute.
- Wait around 15 minutes, then reconnect the battery cables.
- Check the error codes have been deleted and the engine management light has gone off.
If the engine light returns, then you probably have an issue that requires the attention of a mechanic.
Alternatively, your local garage will be able to reset your engine management light.
Turn the ignition on and off to turn off EML engine warning light
An even simpler way to clear the engine management light is to turn the ignition on and off. This approach achieves the same outcome as the previous step, but without disconnecting the battery.
Turn the ignition on and off three times, pausing a second between each cycle.
The engine management light should go off. If it doesn’t, consult a mechanic.
Wait for the engine management light to go off
If you notice the engine management light has come on, you could wait a few days to see if it goes off by itself.
The light may come on due to some internal glitch. However, if the EML remains on after this period, you should take steps to determine the problem.
Engine warning light has come back on
You may also find that the engine light goes off for a period, then returns.
Once again, this means you should take action to work out what the issue is that is causing the check engine warning light to come on.
The easiest way to diagnose why the engine management light is coming on is to take your car to a mechanic.
Why is my engine light coming on?
Unless it is due to a glitch, there are a number of possible reasons why your engine management light is on.
Here are some of the more common reasons as to why your EML check engine light might be on:
Loose petrol cap
A loose petrol cap is one of the most common causes for the engine management light to come on.
Check the cap to see if it is damaged. If it is, replace the cap with a new one.
Oxygen sensor
Your engine management light may come on if the oxygen sensor detects your car is running fuel which is too rich or too lean.
There may also be a fault with the sensor. This can be remedied by reprogramming/recalibrating the engine control unit (ECU). Your mechanic will be able to do this for you.
Diesel particulate filter (DPF)
Your engine management light may come on if there is a fault with your DPF - a filter that captures and stores exhaust soot and essentially helps make your engine less polluting.
A faulty differential pressure sensor may also mean the car's engine control unit doesn’t know the status of the DFP, which could cause the engine management light to come on.
Mass airflow sensor
The mass airflow sensor is essential for your car’s performance. This sensor helps your engine run efficiently.
The ECU needs data from the mass airflow sensor to determine how much fuel to add to the combustion chambers so it matches the amount of air flowing into the engine.
A missing, clogged or damaged air filter can itself damage the mass airflow sensor and cause the engine light to come on.
Ignition system
In a petrol car, issues with your ignition system's spark plugs or coils may cause the engine management light to come on.
Will my car pass an MOT if the engine light is on, or will my car fail MOT with engine light on?
In short, no. your car will not pass an MOT if the engine management light is on.
Stricter MOT rules were introduced in 2018 meaning any car undergoing an MOT test with an illuminated engine management light (whether it’s a red or amber warning light) would automatically fail.
Taking your car to the garage for engine light issues
As mentioned, if any of these processes for how to reset an engine management light are outside of your mechanical/electrical knowledge, or if you simply do not have the time or inclination, then your local garage will be able to assist you in diagnosing and solving your engine management light issue and in undertaking an engine management light reset.
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