If you’ve ever been out driving and your check engine light comes on, you know that sinking feeling that your car has some problems that need to be taken care of. Like most drivers, you probably make a note of it and plan to call for an appointment with your local mechanic. There are many possible reasons your check engine light can come on, so if you’ve ever been curious about why your check engine light goes off – then keep reading for some possibilities.

Engine Thermostat

Your engine typically runs between 195-220 degrees fahrenheit, and your engine thermostat regulates your coolant temperatures. As engine temperatures reach the right zone, the thermostat opens allowing coolant to flow to the radiator. A faulty engine thermostat can cause overheating when the thermostat doesn’t open properly.

Fuel Injector

Each engine cylinder has a fuel injector which is a small, electronically activated valve that regulates how much fuel is sprayed into the cylinder during the intake cycle. Our fuel has impurities and when these are combined with carbon from the combustion process – it can cause the miniscule holes in the injector tips to plug or clog. Complete clogging can force the fuel injector to stay open and continuously leak fuel into the cylinder which can cause the engine to run roughly.

Ignition Coils and the check engine light

Your ignition coils deliver an electrical pulse to each spark plug. When the engine computer sends a signal, the coil releases pent up energy to the spark plugs which ignites the air + fuel mixture. The ignition coils are prone to failure after several years, so if you notice poor fuel economy or decreased engine power – it’s a good idea to have your mechanic check it out.

Vacuum Leak

Your vacuum system helps decrease emissions by routing the fumes from gas evaporating through the engine. Vacuum hoses can crack or dry out when exposed to intense heat or cold. If this is the reason your check engine light turns on, you’ll also want to ask your mechanic to check for cracked fittings and loose connections in your vacuum system.

The Check engine light & Oxygen Sensor Failure

Your oxygen sensor measures the amount of unburnt oxygen in your car’s exhaust. It sends data to the car’s computer which uses that data to regulate the mixture of fuel + air that enters engine cylinders. If your oxygen sensor has failed your car can keep running, but it will burn more fuel and over time can damage your spark plugs and catalytic converter.

Dirty 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 can be susceptible to oil and dirt clean up. When not working, it can cause your air to fuel ratio to be off which can cause failures in other areas of the engine like decreased fuel economy and engine performance.

Loose or faulty gas cap

Your gas cap and valves in your gas tank keep gas from escaping and functions to circulate your gas. If your gas cap is loose, it may cause you to lose fuel due to evaporation or for your fuel to circulate improperly.

Faulty Catalytic Converter & Check Engine light

Your catalytic converter changes carbon monoxide to carbon dioxide which helps protect the environment. When your catalytic converter is faulty, it reduces your fuel economy and engine performance. It’s important to note that replacing it is not always the answer. Typically, issues with your catalytic converter can be caused by something else – like a blown head gasket which can force burnt coolant vapor into your exhaust.

When your check engine light turns on, these are just some of the common causes to look for. For your peace of mind, it’s always best to make an appointment with your mechanic so they can run tests and diagnose the exact issue. The next time your check engine light turns on, simply give us a call – we’d love to check it out and get you back on the road again.