8 Common Causes Of Check Engine Light Turning On

Check Engine Light Turning On

8 Common Causes Of Check Engine Light Turning On

If you have owned a car for quite some time, you probably have experienced the check engine light suddenly turning on as you’re driving. However, this might be their first time encountering such a situation for new car drivers. 

So, what do you do when your check engine light flashes on your dashboard? Depending on what’s causing the problem and whether it’s a static or blinking light, you might need to get it checked as soon as possible. 

This post will discuss why a check engine warning occurs in a car and how to address it. 


What Causes Check Engine Light To Light Up?

  1. Loose Gas Tank Cap

The gas tank cap is the first thing you should check since it’s easy to access. It could either be loose when you pour gas into the gas tank, or the seal inside is faulty. 

Both scenarios allow excess air into the tank, which causes issues in the air-fuel mixture. The solution to this problem is relatively simple. Make sure to always tighten the gas tank cap. If that doesn’t work, consider changing the gas tank cap altogether. 

  1. Bad Car Battery

If your car has an old battery, you should also suspect it to be causing the check engine light warning. A dying car battery supplies low voltage to your car’s computer and triggers false error codes such as a battery charge warning light.  

Most car batteries can last three to four years. Hence, if your battery is older than this figure, it’s time to replace it. 

  1. Air Intake Issues

Another common cause of engine warnings in your dashboard is a problem in your car’s air intake system. To check if this is causing any issues to your car, pop up the hood and check for loose hoses, punctures, or bad seals. 

Any issues in the air intake allow excess air into the system and mess up the air-to-fuel mixture ratio. You should also look at the Mass Airflow Sensor (MAF) and see if it’s already faulty. If it’s already worn out, either get the MAF cleaned or replace it altogether. 

  1. Electrical Problems

Electronic and electric fault in your car is another reason your check engine warning was activated. Anything from short circuits or a broken cable can cause the light to turn on. Most cars also have a separate icon that signals a problem in the electrical system. 

If you see the EPC icon on your dashboard, it means Electronic Power Control Fault. This warning indicates trouble in a car system that uses electricity, such as cruise control. Use an onboard diagnostics (OBD) reader to find what car component is faulty. 

  1. Bad Car Alternator

An irregular alternator voltage may also be causing the check engine warning to light up on your dashboard. Hence, check the alternator voltage output using a multimeter. 

A good alternator usually has a voltage reading between 13.5 and 15 volts. If the voltage is higher or lower than this range, it will trigger the check engine warning. Fortunately, you can fix this simple issue with just a few tools. 

  1. Faulty Sensor

The oxygen sensor can also trigger the check engine light warning. This sensor is located on the exhaust system of most car models. If the oxygen sensor is faulty, it can give a wrong reading of the exhaust fumes, which will trigger the check engine light to turn on. 

Use an OBD tool to check for any faulty sensors or components in your car. The most recommended solution to a faulty oxygen sensor is to replace it entirely. Taking it off and cleaning it can also work in some cases.  

  1. Worn Out Spark Plugs

Bad spark plugs and cables can also cause the check engine icon to light up. However, very few cases attribute the dashboard warning to worn-out spark plugs. Regardless, you must ensure to change your spark plugs on a regular service interval.

Change it every 30,000 to 50,000 miles if you have conventional spark plugs. Meanwhile, long-life spark plugs with platinum or iridium tips require replacement every 60,000 to 150,000 miles. Check your car’s user manual since this figure varies from one car model to another.  

  1. Clogged Catalytic Converter

The catalytic converter is located under your car on the exhaust system. A dirty catalytic converter can also cause the check engine icon to light up in your dashboard. This car component gets dirty over time, and once it’s clogged, it will give a wrong reading from your oxygen sensor. 

Replace the old catalytic converter with a new one. However, you might leave this work to a professional since it involves precise metal cutting.  

Check Engine Light Turning On

Is Your Check Engine Light Static or Flashing?  

You check engine light behaves in two ways- static or flashing. Both signals indicate that something’s wrong with your engine. 

Static or Steady Light

A yellow static check engine light means the problem isn’t too serious, and you can continue driving your car. However, be sure to be extra vigilant when driving under this circumstance. Moreover, you need to get a diagnostics test for your car in the next few days.

Blinking Light

A red blinking light means a severe issue with your engine, such as an oil pressure issue, problems with brakes, or a damaged component. A misfire in the engine is one of the most common causes of the red blinking light. If not addressed immediately, a misfire can damage the catalytic converter. 

What To Do When You See the Check Engine Light? 

Because a check engine light could mean a lot of things, it’s best if you get it to a trusted auto repair specialist. An expert mechanic can quickly diagnose and address the problem within a few hours or days. 

However, if you are knowledgeable about cars or don’t want the extra cost without assessing the warning, first make sure to use an OBD. This tool can help you identify the problem and troubleshoot it, especially if it’s a minor one. 


When you see the check engine light in your dashboard, it’s best to assess what is causing the problem. However, if you don’t know how to troubleshoot a car, it’s best to leave it to the experts like Z Auto Service

Our company has certified mechanics and the latest tools to diagnose and repair your car. Get a car service appointment online, and we’ll get your car working in no time. 

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