We've all been there. Driving home after a long day at work when all of the sudden that ominous check engine light shines brightly on your car's instrument panel. As questions of what the issue could be start popping into your head, all you can see are dollar signs. Especially considering most mechanics charge a premium just to diagnose the issue.

Well, don't panic yet. There are ways to self-diagnose the issue free of charge.

Self-diagnosing your check engine light

The internet can be your friend when it comes to self-diagnosing auto-related issues, but you can believe everything you read online. It's always a good idea to have a certified professional run a diagnostic to determine the problem.

The first step to conducting a self-diagnosis is to know the most common reasons your check engine light might turn on in the first place.

5 common reasons your check engine light is on

  • Faulty oxygen sensor: This device measures the amount of fuel your engine is burning (whether it is too much or not enough). A new O2 sensor will run around $200.
  • Loose or missing gas cap: This is one of the more common reasons your check engine light comes on: You forgot to replace the gas cap after refueling. If the gas cap is in place, make sure it is properly tightened. If needed, a new gas cap should be less than $50 depending on the make and model of your car.
  • Spark plug(s) malfunctioning: Replacing spark plugs is one of the relatively easier and more affordable fixes. If a bad spark plug is determined to be the culprit, replacing it yourself will run $20 to $30. 
  • Faulty mass airflow sensor (MAS): Average cost to replace the MAS is $375.
  • Catalytic converter has gone bad: This is one of the pricier fixes associated with your check engine light. A new catalytic converter can cost upward of $2,000 or more.

Diagnosing your check engine light

Here three ways to get a reliable diagnosis and know exactly what is wrong:

  1. Come to Ace Auto Parts: Here at Ace Auto Parts, our certified automotive specialists can run a quick diagnosis and determine the issue in a matter of minutes. 
  2. Buy an OBD-II scan tool: There are affordable tools that allow you to run a diagnosis yourself. Call us today for more information on these devices.
  3. Visit your local mechanic/dealer: Your mechanic or local dealership should have the proper diagnostic tools on hand, however, you should be prepared to wait and pay a higher surcharge.

Call us today for more information.