What to Do When the Check Engine Light Comes On

It’s the one light on the dashboard of your vehicle that causes the most fear and anxiety when you see it: the Check Engine light. When it turns on, you know something is not right, even if your vehicle seems to be running fine. So what do you do when your vehicle’s Check Engine light comes on, and what causes Check Engine lights to turn on? Read on to learn more about what an illuminated Check Engine light means, how to decode it, and how O’Reilly Auto Parts’ O’Reilly VeriScan diagnostic testing can help you diagnose your Check Engine light codes.

What Causes a Check Engine Light?

The Check Engine light, also known as the malfunction indicator lamp, activates when the computer in your vehicle detects a fault or issue from an electrical component or sensor on the engine, transmission, or exhaust system. In some cases, the Check Engine light may simply be an image or icon of an engine, or it may use text that says “Check Engine”, “Service Engine Soon”, or a variety of other notifications. The most basic explanation for what causes a Check Engine light is that a sensor communicating with the engine control module detects behavior that indicates a component failure or readings outside of its normal or acceptable range. This can be an indicator of a severe problem, or a minor or momentary problem that has caused readings that are out of specification. It is important to have a professional mechanic inspect your car or use an OBD-II scanner to retrieve the diagnostic trouble codes (DTCs) related to the check engine light. You can also stop by your local O’Reilly Auto Parts Store for a free VeriScan Check Engine light test.

The Check Engine light indicates a problem with your vehicle – however, it does not provide specific information about what needs to be fixed. The issue could range from a loose gas cap or faulty oxygen sensor to a more complex problem with the engine or emissions system. Other problems that can activate the light include faulty spark plugs, ignition coils or wires, a bad mass air flow (MAF) sensor, a failing or clogged catalytic converter, intake vacuum leaks, or leaks in the evaporative emissions system. Any electronic sensor or component on your vehicle that detects engine performance anomalies can cause the Check Engine Light to activate, and a lack of communication with the sensor may also result in a trouble code.

Some of the issues that can cause the light to illuminate will not affect how a vehicle will run and drive, but other issues can seriously affect the performance of a vehicle and allow damage to the engine, electronics, or other components to occur if not addressed. If the issue is severe enough, the Check Engine light may also blink or flash. These types of issues may cause severe or catastrophic damage to your vehicle if they are not addressed immediately. No matter the issue, vehicles should be diagnosed as soon as possible after the Check Engine light activates to limit the risk of more severe damage or catastrophic engine failure.

Diagnosing Check Engine Light Codes at O'Reilly Auto Parts

Since 1996, automotive manufacturers have used OBD-II protocols to determine engine issues using Diagnostic Trouble Codes (DTCs). The codes are read by a diagnostic scan tool or OBD-II scanner through a universal connector that is normally located under or near the dash of a vehicle.

To find out what diagnostic codes are activating your Check Engine light, you will need to take your vehicle to a mechanic or borrow or purchase a diagnostic tool that can read the codes. You can also go to your local O’Reilly Auto Parts store to purchase an OBD-II scanner or ask one of our trusted parts professionals to scan your Check Engine light for free with O'Reilly VeriScan. O’Reilly VeriScan is a quick, free diagnostic test that reads the Check Engine light codes and generates a detailed report to help you identify possible causes and repair solutions. These fixes are verified by ASE-certified master technicians, providing the best possible guidance before starting your repair. Our parts professionals will review the report with you, and can recommend the best products and tools to make the repair yourself. They can also recommend a trusted local repair shop if you’re not comfortable taking on the repair yourself. To learn more about common Check Engine light codes and what they mean, check out our helpful article.

Can O'Reilly Clear Check Engine Light Codes?

While O’Reilly Auto Parts can scan and read your illuminated Check Engine light with our O’Reilly VeriScan code reading service, we can not clear your Check Engine light codes. To clear your codes, it’s recommended to make any necessary repairs to fix the issue before using an OBD-II scan code to clear the Check Engine light code from your vehicle’s dashboard.