You’re driving down the road, minding your own business when your check engine light comes on. You have options from ignoring that bright light to pulling over and calling your mechanic right away. We’re guessing you land somewhere in between, but did you know there are a variety of reasons you check engine light comes on? Some are more serious than others – so if you want to know what’s really wrong when your check engine light comes on, then keep reading.

Check engine light & Loose or faulty gas cap

That’s right. That last time you filled up and forgot to tighten your gas cap can lead to a check engine warning. The lines and valves in your gas tank recirculate gas and keep the gas from escaping. If your gas cap is loose, it may cause you to lose fuel due to evaporation or for your fuel system to circulate improperly. Checking your gas cap is a good place to start when your check engine light comes out of nowhere.

Worn spark plugs

Your spark plugs ignite a mixture of fuel and air to create combustion and to power your engine’s cylinders. If your spark plugs aren’t firing right, it can cause an engine to misfire which can cause weaker engine performance.

Faulty catalytic converter

Your catalytic converter changes carbon monoxide into carbon dioxide which helps protect the environment. A faulty catalytic converter can reduce engine performance, increase emissions, and decrease fuel efficiency. If the problem is your catalytic converter, replacing it is not always the answer. This issue is typically caused by something else in your engine like a blown gasket head which can force burnt coolant vapor into your exhaust. Bring your car into your mechanic for a full diagnosis.

Dirty or faulty MAS airflow sensor

Your MAS airflow sensor determines how much fuel is needed to run the engine. It measures the amount of air entering the engine, and is susceptible to oil and dirt buildup. If your air to fuel ratio is off, it can cause failures in other areas of the engine, decrease fuel economy, and decrease engine performance. If this is the issue that triggered your check engine light, it may just need a cleaning. If cleaning doesn’t do the trick, then it may need replacing.

Oxygen sensor failure

Your oxygen sensor measures the amount of unburnt oxygen in your car’s exhaust system. This sensor sends data to your car’s computer which uses this data to regulate the mixture of air & fuel that enters your cylinders. Your engine can keep running with this sensor failure, but it will burn more fuel. If left unchecked, it can become damaged and cause problems for your spark plugs and catalytic converter.

Vacuum Leak

Your vacuum system helps decrease emissions by routing the fumes as gas evaporates through the engine. Hoses can crack or dry out especially if exposed to intense heat or cold. Ask your mechanic to check hoses and fittings to make sure everything is in working order.

Battery and the Check Engine Light

This is probably a no-brainer, but when your battery dies – your check engine light could just be alerting you to an issue with your battery.

Ignition Coil

Your ignition coils deliver electrical pulses to each spark plug. When your engine’s computer sends a signal, the coil releases pent up energy to your spark plugs and ignites the air-fuel mixture to get your engine going. They can be prone to failure after several years. Symptoms of issues with your ignition coil include: poor fuel economy, and decreased engine power.

Fuel Injector

Each cylinder in your car has one – which is a small, electronically activated valve that regulates how much fuel is sprayed into the cylinder during the intake cycle. All fuel has some impurities and when these impurities and carbon from combustion, it can cause holes in the injector tip to plug or clog altogether. If your fuel injector is completely clogged, your fuel injector can get stuck open and leak fuel into the cylinder. This can cause your engine to run roughly.

Engine thermostat

A typical engine runs between 195 – 220 degree Farenheit. Your engine thermostat regulates coolant temperatures. As temperatures begin to heat up, your thermostat opens to allow coolant to flow to your radiator. It will also close when it senses the engine is cool. A faulty thermostat could cause your car to overheat.

Your check engine light is a sign that something is not working properly in your vehicle. For your peace of mind, we recommend making an appointment so our mechanics can take a look and get you back on the road again.