Top Triggers of the Check Engine Light

Top Triggers of the Check Engine Light

Top Triggers of the Check Engine LightWhen it comes to identifying car trouble there are few things that make a driver's heart sink as fast as the check engine light coming on. While you may fear it, this light should actually be thanked, as most check engine light issues start out pretty small. As long as you have diagnostics and repairs completed quickly, you generally won't have much to worry about in terms of expensive repairs or hefty downtimes. Let's take a peek at some of the most common triggers of the check engine light.

Broken Gas Cap

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

Oxygen Sensor

The oxygen (O2) 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 O2 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.

Mass Air Flow Sensor

The mass air flow (MAF) 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 gas.


In most cases of engine 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 are not igniting the air and fuel mix, or the timing is off. Another cause of misfiring is faulty ignition coils.

Failed Catalytic Converter

As mentioned, a failed oxygen (O2) 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 repair shop immediately. For professional check engine light repair in Lancaster visit the team at McKonly's Garage. We strive to provide fast and effective auto repair for all makes and models. Give us a call at (717) 208-8210 to schedule an appointment for superior auto repair in Lancaster or the surrounding area today!

McKonly's Garage Blog

Written and Published By MORBiZ

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