Common Triggers of the Check Engine Light

Common Triggers of the Check Engine LightAside from a light saber, the check engine light seems to be one of the most feared lights in all the galaxy. While this little icon can incite fears of massive engine repairs it is much more likely that the issue at hand is something simple and inexpensive to fix, assuming you fix it right away. The longer you let that light burn, the worse the problem that triggered it will get, resulting in massively expensive and unnecessary repairs. Here are a few of the most common reasons the check engine light may illuminate.

Loose or Broken Gas Cap

Believe it or not a loose, broken or cracked gas cap can actually cause the check engine light to come on. This is because the EVAP system, which detects fuel vapors, can trigger the light should those vapors escape out of the filler hose. Always be sure to tighten your gas cap after filling up!

Oxygen Sensor

The oxygen sensor is integrated into the exhaust system to measure how much oxygen is in the emissions. This reading helps calculate the proper air/fuel mixture for the engine. If the sensor fails it could result in excessive fuel being burnt, which could lead to a much more expensive problem with the catalytic converter… more on that below.

MAF Sensor

The mass air flow sensor performs a similar function to the oxygen sensor, in that it's measurements help dictate the air/fuel mix, but it calculates how much of the incoming air should be mixed with the fuel.


In most cases of misfiring you'll be able to tell without the assistance of the check engine light, as the car will generally idle very rough or even stall. Misfiring occurs when one or more spark plugs is not igniting the air and fuel mix, or the timing is off. It can also be caused by faulty ignition coils.

Failed Catalytic Converter

As mentioned, a failed oxygen sensor could lead to damage of the catalytic converter due to excessive fuel being burnt. This part is one of the most expensive parts of a car to replace, but it won't go bad on its own in most cases. This is why it's crucial to visit the auto shop as soon as the check engine light comes on.

When the check engine light comes on head to the auto shop immediately. For professional check engine light repair in Phoenix visit Gearhead Auto Center. Our professional auto repair technicians will have you back on the road in no time. Give us a call at (602) 497-3541 to schedule expert auto repair in Phoenix today.

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Written & Published By MORBiZ

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