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Examining Common Reasons Why Your Check Engine Light Is On

Last updated 4 years ago

An illuminated check engine light should not be taken lightly. If your vehicle has a check engine light, take it to a car repair shop right away to prevent serious damage. Here are some of the common reasons why a check engine light turns on.

Loose or Broken Gas Cap

Probably the most common reason for an illuminated check engine light is a gas cap that hasn’t been screwed on tightly. This also happens to be the easiest thing to repair—just give the gas cap a few turns, and drive around for a few miles to see if the check engine light turns off. In some cases the gas cap is cracked and needs to be replaced at an auto repair shop.

Faulty Oxygen Sensor

The oxygen sensor’s readings help the vehicle’s on-board computer determine how much fuel should be burned. Over time, oxygen sensors wear out and become covered in oil ash, reducing their ability to provide accurate readings. A faulty oxygen sensor increases vehicle emissions and decreases fuel efficiency.

Replace Catalytic Convertor

Catalytic convertors transform harmful carbon monoxide emissions into harmless compounds that are friendlier to the environment. If the catalytic convertor isn’t working it will decrease your fuel efficiency and increase vehicle emissions.

Malfunctioning Mass Airflow Sensor

This important component tells the on-board computer how much fuel to add based on how much air is coming into the engine. If your vehicle is experiencing reduced fuel economy or is starting to stall, it may have a malfunctioning mass airflow sensor.

Bad Spark Plugs or Wires

Failing spark plugs cause the engine to misfire, which negatively affects both emissions and efficiency. Cars made before 1996 should have their spark plugs replaced every 25,000-30,000 miles. Spark plugs on newer cars need to be replaced every 100,000 miles or as-needed.

For top-notch auto repair services in the Smyrna and Buckhead areas, come to Dekalb Tire. Visit us online to learn about our maintenance and repair services, and call us at (404) 334-9531 if you have any questions for our automotive experts.


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