Why’s My Check Engine Light Blinking And What Should We Do?

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Why is my check engine light blinking
check engine light blinking

Check engine light blinking

This causes a quick panic- ‘Why is my check engine light on?’ and you then hurry to the destination hoping that the car won’t break down on the way.

Whether the engine isn’t getting enough air, or there is a serious issue at hand, the immediate focus becomes getting the problem fixed and the light turned off.

Here are the most common reasons why your ‘check engine’ light is coming on, and what needs to be done to fix the problem.

Why is my Check Engine Light Blinking?

There are a handful of reasons that cause check engine lights to blink.

If you don’t notice anything weird about how the car is driving when the check engine light comes on, check the gas cap first. You may just need to tighten it.

If there is something wrong, the car emits hydrocarbons when not in use due to the lack of a seal on the tank, the tank will lose pressure and the gas won’t perform well.  

Why is my check engine light blinking

Why is my check engine light blinking

The engine’s computer will pick up on this over time, which is what turns the light on. This is a simple fix – just go to an auto parts store or dealership and buy a new gas cap.

1. The Mass Airflow Sensor (MAF) Has a Faulty Sensor and is Reporting an Inaccurate Amount Of Air Being Pulled Into The Engine.

You may have a dysfunctional mass airflow sensor.

As a result of this, the engine will add too much or too little fuel and can cause reduced gas mileage or stalling.

A mechanic can fix this right away. 

This puts extra pressure on the engine, forcing it to work harder for fewer miles.

After a while, a faulty MAF can cause damage to the ignition coils or O2 sensors, and clog the catalytic convertor.

What should I do if I have a misfiring cylinder?

What should I do if I have a misfiring cylinder?

This causes the engine to add an incorrect amount of fuel and can cause reduced gas mileage or stalling. Luckily, the problem is easy to detect and easy fix for your mechanic. This puts extra pressure on the engine, forcing it to work harder for fewer miles.

Over time, a faulty MAF can cause damage to the ignition coils or O2 sensors, and clog the catalytic convertor. Often, the problem lies in the air filter not being replaced or being improperly installed. Check this first before replacing the MAF, you can save money in the long run by regularly changing the air filter. A replacement will typically cost between $200-300.

2. It’s Time To Change Your Spark Plugs.

This is one of the most common reasons that actually requires some maintenance. If there isn’t proper spark, the oil/air mixture in the engine isn’t performing optimally. Gas mileage goes down, engine wear goes up, and you’ll see slower accelerating. The car will burn through gas very quickly.

On vehicles made before 1996, spark plugs should be changed out after 25,000 miles, on newer vehicles they can often last nearly 100,000 miles. They should be accessible right under the hood of the car, and videos on YouTube can show you how to change them yourself.

Check the air filter and spark plugs. Maybe one or both are worn out, or perhaps weren’t set up correctly in the first place. Check this first before anything else, and be sure to regularly change your air filter.

The wires deliver the spark from the ignition coil to the plugs. If the plugs are worn out, the spark will misfire. If this process is not happening correctly, it can cause severe damage to the engine over time. Another common issue is the wires. Either way, without a proper spark, the oil/air mixture in the engine isn’t performing optimally and can clog the catalytic convertor.

The car will burn through gas at a much higher rate when this happens because the wires deliver the spark from the ignition coil to the plugs. If the plugs are worn out, the spark will misfire, and that’s how we got into this whole situation in the first place. Be careful, because you might see significant engine damage.

On vehicles made before 1996, spark plugs should be changed out after 25,000 miles, on newer vehicles they can often last up to 100,000 miles. They are usually accessible right under the hood of the car, and videos on YouTube can show you how to change them yourself.

3. The Catalytic Converter Is Shot

 Your car will emit higher emissions if the carbon monoxide isn’t properly converted to carbon dioxide, and the engine light will come because the vehicle is running at higher temperatures. This means extra wear on the engine.

The vehicle will likely fail an emissions test if there is a problem with the catalytic convertor. When it is clogged, the car is emitting dirtier fumes at a much higher rate. This can be expensive, so keep up on other engine-related maintenance.

You will notice severely decreased acceleration when the catalytic convertor is failing. It shouldn’t fail if other engine maintenance is maintained, most problems with this part are a result of other issues not being taken care of promptly.

4. The Gas Cap Isn’t On Correctly

This is a sure trigger. Not only will your car emit hydrocarbons when not in use due to the lack of a seal on the tank, the tank will lose pressure and the gas won’t perform well. 

The engine’s computer will pick up on this over time, which is what turns the light on.

This is a simple fix – just go to an auto parts store or dealership and buy a new gas cap.

Perhaps you left it at the gas station. Check the gas cap first – you may just need to tighten it.

5. Change The Oil!

Check Engine with Innova 3160e or 3160g


As simple as it sounds, many people do a terrible job of keeping up on oil changes. There is no dumber way to ruin your car’s lifespan and performance than by not following recommendations on oil changes. They are cheap, quick, and with a little learning, the effort can be done at home in your garage.

6. The O2 Sensor is Worn Out And Needs Replacing.

The oxygen sensor calculates the amount of air in a vehicle’s exhaust system, and if it isn’t working correctly the engine won’t perform as well as it should and you’ll burn through fuel much faster.

how to pass emissions test

Worn out sensors can damage other engine parts such as spark plugs and the catalytic convertor. If the sensor isn’t replaced, your fuel economy will continue getting worse, until you are losing up to 40%. Regular vehicles typically have 2-4 O2 sensors.

Using an best bluetooth obd2 scanner will tell you which one needs replacing. Your car’s manual should detail how to change them, and all you need to do is unclip the old one and clip on the new one.

Can You Reset The Check Engine Light By Disconnecting The Battery?

You have a check engine light on. The question that comes to your mind is: what is the problem? Once you’re able to determine the issue and fix it, you now have to reset the check engine light and go about your day. So is it possible to reset the light just by disconnecting the battery? The answer is yes. In the event if your check engine light is on, follow these instructions:

  1. If you have a code scanner, you’ll need to connect it to your on-board diagnostic connector. In most vehicles, this can be located your steering column. Turn off all accessories and turn on the ignition.
  2. Now, press the “read” button so the scanner can view the engine codes. Make a note of the codes in the order of which they appear so you can refer to them should the car need repairs.
  3. Once the scan is complete, erase the codes by simply using the “erase” button on your scanner.

However, disconnecting the battery is the old, but tried and true way of resetting the check engine light. In order to do it this way, here’s how to do it:

  1. Using a wrench, disconnect the positive and negative cables.
  2. To ensure that electricity is draining properly from the capacitor, hold down on your horn for 30 seconds.
  3. Please wait 15 minutes prior to reconnecting your battery. Once reconnected, the codes should be erased and the check engine light should be gone. Keep in mind that this process may not work with all vehicle computers. If the light itself remains on after the battery is completely disconnected, that’s when you know that you have a serious problem. At that point, you’ll need to have it serviced.

Disconnecting the battery is one way to reset the check engine light. Sometimes, it can also be an indicator that you really do have a serious problem. Either way, you can be able to reset the check engine light and erase the codes simply by disconnecting the battery. Alternatively, you can do this by using your code scanner.

Conclusion

There are a number of reasons why your check engine light might be on. Always remember, it is important to take action immediately!

Don’t just keep driving on it – this will only lead to more probems down the line. Often, it can be fixed quickly and cheaply without much trouble.

Many people don’t know what to do when their check engine light comes on. Give this article a share on social media so that more people can learn.

If you’ve got a crazy story about a seized engine or a check engine light, throw it in the comments down below. Let’s get a conversation going!

Mike Cross

Mike Cross

You have to look for teachers. If you want to be a mechanic, go hang out with mechanics.

1 thought on “Why’s My Check Engine Light Blinking And What Should We Do?”

  1. Hey Mike, I have a 2013 Hyundai Eqqus. My check engine light was flashing and it turns out my alternator was gone. I have since replaced it. But my it continues to blink occasionally. Please explain what may be the problem. Thanks Karen

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