Top 5 Reasons Your Check Engine Light is On

Top 5 Reasons Your Check Engine Light is OnWhile many people fear the check engine light, you should really embrace it. This light will illuminate if the computer system in your vehicle detects an issue with one of numerous possible parts. There are hundreds of reasons the check engine light could come on, but many of them are quite small and don't require much effort to fix. However, should they go unchecked you will soon find that your car will begin to run worse and worse and require more money and more time to fix. Here are five common reasons the check engine light will come on.

Malfunctioning o2 Sensor

The oxygen sensor is located in the exhaust system and helps to determine how much gasoline is needed to create the correct air/fuel mixture. If it malfunctions it could result in your car running rich, meaning it will burn excessive gasoline, thus lowering your MPGs.

Failed MAF sensor

Another common sensor failure that triggers the light is the Mass Air Flow Sensor. This too helps calculate the right gas/air mix by monitoring incoming air. A failed MAF sensor can also result in decreased fuel efficiency.

Failed Catalytic Converter

If either of the two problems above trigger the light, but they go unrepaired, it can result in a failed catalytic converter. This is the part of the exhaust system that converts hazardous fumes into less harmful emissions. If it fails your car won't pass a smog test and it is expensive to fix.


Did your vehicle start running rough and is now showing the check engine light? Misfiring can be caused by corroded spark plugs or ignition coils. It can happen in one or more cylinders. Head to a repair shop to figure out what's causing the rough idle.

Loose or Broken Gas Cap

The best case scenario would be finding out that you simply forgot to tighten the gas cap last time you filled up. The EVAP system monitors fuel vapors that could evaporate up the filler tube. If it detects them the light will come on, thus saving you gas!

Really, the check engine light just wants to save you gas! If you need check engine light diagnostics in Denton then be sure to visit Strande's Garage. We offer expert diagnostics and auto repair for all makes and models. To learn more about our services or to request an estimate for professional auto repair in Denton give us a call at (940) 566-2156 today!