Solving the Blinking Check Engine Light: Causes, Concerns, and Possible Fixes

Solving the Blinking Check Engine Light: Causes, Concerns, and Possible Fixes

February 20, 2024 0 By CarGuy

Although many people hate it, the check engine light is one essential indicator that tells us that we have a potential problem with our vehicle. Especially when you have a blinking check engine light. This time you know that your car needs immediate attention.

In this guide, we will explore a lot of important aspects. Such as the causes, consequences, and solutions in order to ensure vehicle safety and proper performance.

Understanding the Blinking Check Engine Light

The check engine light or MIL is an integral part of each onboard diagnostics system, known as OBD2.

This light appears whenever you have a problem with the car. The ECU or PCM depending on the car you have is monitoring all of the sensors and the work of the engine. If the computer notices a malfunction, you will start to experience an illuminated check engine light on the dash.

A blinking check engine light, however, can indicate a more serious problem that requires immediate attention. This light, unlike the steady glowing check engine light, means that you need to take your car to the shop immediately and prevent potential engine damage or other safety hazards.

Causes of a Blinking Check Engine Light

Now let’s take a look at the possible causes for the blinking check engine light and learn more about what could trigger this light to start flashing on the dashboard.

1. Misfiring Engine

One of the most common causes for the blinking check engine light is the misfiring engine. So, what are engine misfires, and why they are a problem?

Well, an engine misfire is whenever you have an abnormal combustion. So, what this means?

This means that the explosions inside of the cylinders are pretty uneven. They can be premature and delayed.

If this happens, the engine is misfiring. This will trigger a check engine light, as well as other symptoms such as engine vibrations, rough engine idle, poor engine work, and poor fuel economy.

2. Catalytic Converter Damage

A blinking check engine light can be an indication that you have a problem with your catalytic converter. So, what is a catalytic converter?

This converter is an emissions device mounted on the exhaust, right after the exhaust manifold. Inside this component, there is a catalyst that activates and destroys the harmful particles.

In many cases, these catalytic converters can fail. Whenever they fail, they usually end up being clogged up.

And this situation triggers the check engine light and a code like the P0420 or the P0430.

3. Oxygen Sensor Malfunction

Another component that can often trigger a blinking check engine light is an oxygen sensor malfunction.

There are at least two of these O2 sensors in your car. One before the catalytic converter and one after the catalytic converter.

The one before is known as the upstream sensor and the second is the downstream sensor.

Both of these sensors can fail and cause problems like this to develop. In many cases, the solution to this issue is to replace the O2 sensor.

4. Loose or Missing Gas Cap

Something as simple as a loose or missing gas cap can also cause a blinking check engine light to appear on the dash. So, why is this the case?

Well, this is the case because the gas cap plays a very vital role in the EVAP system. This system collects harmful fumes from the gas tank and redirects them to the intake manifold.

If the gas cap is not sealing, you will get a check engine light. Also, any vacuum leak by the EVAP system will trigger a check engine light as well.

5. Ignition System Problems

Problems with the ignition system can also trigger a blinking check engine light.

When it comes to ignition, there could be problems with the ignition coil, spark plugs, ignition module, and so on.

Specifically, problems with the spark plugs and coils can also cause your engine to misfire a lot.

Concerns with Ignoring a Blinking Check Engine Light

Now let’s take a look at why you should not ignore the check engine light. What are the consequences of ignoring this problem? Let’s find out.

1. Engine Damage

Ignoring the blinking check engine light can lead to engine damage in the long run. Let’s take for example the engine misfires, this is a problem that should not be ignored because it affects a lot of internal components.

This problem can lead to poor emissions, poor fuel economy, as well as damage to the catalytic converter. And catalytic converters are some of the most expensive parts in your engine.

2. Reduced Performance

The blinking check engine light as we noted means that you have a significant engine problem. This can mean that the engine will go into something known as limp mode. So, what is limp mode?

Limp mode is a situation where the engine reduces the RPM and limits you to drive into certain RPM and certain gears. Thus the name limp mode. Overall, this means that the engine performance will be reduced significantly.

3. Safety Hazards

A blinking check engine light can also cause safety hazards. For example, if the car enters limp mode on the highway can be potentially a dangerous situation.

This is why we don’t advise that you drive on the highway with such a problem. Because you never know what will happen and this can lead to potentially hazardous situations on the road.

4. Increased Repair Costs

This problem is not a problem that can wait. The more you wait, the more damage could be done to the engine. Resulting in expensive repairs.

For example, if you delay these repairs, the catalytic converter can fail, or some other component in the engine.

Fixing the problem immediately will prevent further damage and expensive repairs.

5. Environmental Impact

This type of problem also has some environmental impact. Let’s say that the engine is misfiring, in this situation, you will have poor emissions.

Whenever you have poor emissions, the car will pollute a lot more and you can also fail the emissions testing if you have to register the car in the near future.

So, it is really important that you service the car in order to reduce the environmental impact.

Possible Solutions for a Blinking Check Engine Light

Now let’s take a look at the possible solutions for this problem.

1. Pull Over Safely

If you notice the check engine light blinking while driving on the highway. It is a good idea to pull over at the nearest safe place.

A safe place is a gas station, or a parking lot if there is an empty lot in your surroundings.

Or if there is a repair garage around, make sure that you adjust the speed limit and slowly limp to the nearest service center and let them take care of the blinking check engine light.

2. Check for Codes

If you are a DIY guy, what you can do is grab an OBD2 device. This scanner will allow you to get the trouble codes that are associated with the blinking check engine light.

You need to plug this device into the OBD2 port and let it scan for codes. Then based on the codes, you can move forward with the problem and address the causes.

3. Address Immediate Issues

Let’s say that you have a blinking check engine light and you found some codes about misfires.

In this case, it is a good idea that you check the code and locate the exact cylinder that is misfiring.

You can swap the ignition coils and spark plugs. If the DTC code moves to the next cylinder, you have found your culprit. Just replace the faulty spark plug or ignition coil.

If the problem is because of the EVAP, make sure that the gas cap is tight.

These are basically the simplest DIY things that anyone can do when it comes to troubleshooting this problem.

Problems with the catalytic converter or O2 sensors require more equipment and a professional approach.

4. Schedule Diagnostic Inspection

If you can’t figure out the root cause of the problem, you better book a meeting with your nearest diagnostician.

There are many shops that do car diagnostics and their job is basically to diagnose car problems.

Then based on this input that they give you, you can move forward and let them sort the problem or find a different shop that can help you out.

5. Do The Recommended Repairs

Once you find what is causing the problem with the blinking check engine light in your car, you can move forward and follow the recommended repairs.

This involves changing components such as the ignition coils, spark plugs, catalytic converter, O2 sensor, or some other components.

Conclusion To Blinking Check Engine Light

The problem with the blinking check engine light should be taken seriously. This light can mean that something serious is wrong with your car.

If you decide to ignore this light, it could lead to engine damage, poor performance, poor fuel economy, poor emissions, safety hazards, and other unwanted situations.

That’s why we advise that you diagnose the car as soon as possible in order to avoid more problems from happening.


What are the common causes for the blinking check engine light?

Common causes for this problem include engine misfires (ignition problems), problems with the O2 sensor, problems with the catalytic converter, and a loose gas cap.

How a blinking check engine light is diagnosed?

This light can only be diagnosed with an OBD2 scanner. This is a diagnostics device that lets you read the trouble codes.

If you want to read more on problems with the check engine light, you can check our article on the P0303 Dodge.