Why is the Check Engine Light On?

Why is the Check Engine Light On?Your car is equipped with tons of sensors and micro computers that monitor how well your vehicle is running in terms of efficiency, power and other performance aspects. If one of these components determines your car is underperforming it can trigger the check engine light. In many cases this light is turned on by a relatively small problem, but if left unchecked, it can grow much bigger, as demonstrated by this first check engine light problem.

Catalytic Converter

One of the most expensive parts to replace on a car is the catalytic converter. This part is designed to convert hazardous exhaust fumes into less harmful emissions. It is very difficult to damage this part, and if it is found it is no longer functioning when running check engine light diagnostics, it's likely the light was on for quite some time. Putting off check engine light diagnostics will result in a need for more expensive repairs.

MAF Sensor

The mass air flow sensor is located at the front of the vehicle and measures the quantities of incoming air in order to determine how much of it needs to be mixed with the gasoline to create proper air/fuel mix for the engine. If it malfunctions it will result in excessive gasoline being burnt, which will reduce fuel efficiency and create fume that are damaging to the catalytic converter.

O2 Sensor

The oxygen sensor is located in the exhaust system and measures the amount of oxygen in the exhaust. This also helps create the proper air/fuel mix. A malfunctioning o2 sensor can also result in excess gas being used.


Misfiring is something you will likely notice on your own, without the help of the light. If your car is running rough at idle or while driving, the check engine light will probably come on, if it isn't already. Misfiring is caused by faulty spark plugs, ignition coils and other parts.

Loose Gas Cap

A best case scenario for check engine light diagnostics is finding out that the gas cap is loose. If the cap is loose it means that fuel vapors may escape out of the filler hose, causing them to evaporate before you ever get a chance to burn them in the engine.

When the check engine light comes on be sure to visit your local auto repair shop for diagnostics before the problem grows any worse. For professional check engine light repair in Stevens Point East head to Auto Select or give us a call at (715) 341-1600 to schedule an appointment. There is no repair or service we can't complete. Any time you need auto repair in Stevens Point East be sure to visit our friendly team.

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Written and Published By MORBiZ