5 Common Reasons Why the Check Engine Light Comes On

Are you wondering what to do when your check engine light comes on? We’ll outline what the check engine light means, if you can drive with the light on, and the most common check engine problems. 

What to Do When Your Check Engine Light Comes On

The first thing to do when your check engine light comes on is to stay calm. The check engine light is part of your onboard diagnostics system and can mean a variety of things. 

Before pulling over and calling a tow truck, try restarting your vehicle. If you notice the check engine light is on while you're driving you'll want to pull over and shut the vehicle down safely. Waiting a few moments and then turning the vehicle back on can sometimes reset any glitches or issues with your computer system.

Solid Check Engine Light vs. Flashing Check Engine Light or Performance Loss

When the check engine light comes on, you shouldn’t ignore it. Taking your vehicle to a trusted mechanic will help diagnose what the problem is, but understanding the difference between a solid and flashing light can help you plan your appointment.

A flashing check engine light is related to performance issues, such as power loss or car shaking. Pulling over immediately when it’s safe to do so will prevent further damage. In this scenario, towing your vehicle to a service centre to check the issue is highly recommended.

If your check engine light is solid, you have a little more time to evaluate your car’s condition. Although you don’t have to head straight to a mechanic, it’s advised that you do so soon to ensure that the solid light doesn’t turn into a flashing, immediate warning.

Reason 1 – Loose, Faulty, or Missing Gas Cap

A loose, faulty, or missing gas cap sends an error message to the car’s computer. The check engine light comes on due to the report of a leak in the vapour recovery system, which is part of your car’s emissions.

Check to make sure your gas cap is tight as this could easily fix the problem. It may take some time before the system recognizes that there is no more vapour leak, but your engine light will eventually turn off. 

Reason 2 – Spark Plugs and Wires

A worn or damaged spark plug can send a check engine error to your car’s system. Additionally, wires that have developed cracks can allow bursts of electricity to escape and thereby cause your electrical system to send an error to the computer. 

To remedy this situation, check your spark plugs and wires carefully. With your engine off, remove your spark plugs and check for wear. Evaluate your wires, and look for any tiny cracks and holes. If you notice any damage, it may be time to replace your spark plugs or wires.

Reason 3 – Oxygen Sensor

The oxygen sensor is located in your vehicle’s emission system and if faulty will send an alert to your car’s computer. Depending on the year, make, and model of your vehicle, it may have multiple oxygen sensors in its system.

Since testing an oxygen sensor involves specialized training and tools, you will need to have this tested by a licensed mechanic to determine whether or not it needs replacing.

Reason 4 - Mass Airflow Sensors

The mass airflow (MAF) sensor measures the amount of gas and air mixture that enters your vehicle’s engine. When a faulty MAF sensor occurs, your check engine light comes on to alert you of a serious engine problem.

Without the correct ratio of gas and air mixture, your engine’s performance will be affected. Basic car maintenance can prevent MAF sensor problems, but having it checked by a professional mechanic is the only way to remedy this problem.

Reason 5 - Catalytic Converter

Your vehicle's catalytic converter is part of the emission system. It converts one gas to another, along with the rest of the exhaust and muffler.

Common problems with a catalytic convertor include corrosion, blockage, or wear. Ultimately, your car is unable to correctly process the gasoline, leading to high levels of damaging emissions. By maintaining your vehicle and flushing the internal systems with professional cleaning, you can avoid damage. Otherwise, you’ll need the services of a professional mechanic.