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How to Handle a Check Engine Light

  • Hovig M
  • Aug 13
  • 4 min read

When your vehicle’s dashboard suddenly lights up with the check engine light, it can be alarming. This warning indicator is designed to alert you to potential issues with your car’s engine or emissions system. Understanding what triggers this light and how to respond can save you time, money, and stress. This guide will walk you through the common causes of check engine light activation, what to do when it happens, and how to keep your vehicle running smoothly.


Common Causes of Check Engine Light


The check engine light can illuminate for a variety of reasons, ranging from minor issues to more serious problems. Here are some of the most frequent causes:


  • Loose or Faulty Gas Cap: A loose or damaged gas cap can cause fuel vapors to leak, triggering the check engine light. This is one of the simplest fixes and often overlooked.

  • Oxygen Sensor Failure: The oxygen sensor measures the amount of unburned oxygen in the exhaust. A faulty sensor can reduce fuel efficiency and increase emissions.

  • Catalytic Converter Issues: The catalytic converter helps reduce harmful emissions. Problems here can cause poor engine performance and increased pollution.

  • Mass Airflow Sensor Problems: This sensor monitors the amount of air entering the engine. If it malfunctions, it can affect the air-fuel mixture and engine performance.

  • Spark Plug or Ignition Coil Issues: Worn spark plugs or faulty ignition coils can cause misfires, leading to rough engine operation and triggering the light.

  • Vacuum Leak: A leak in the vacuum system can cause the engine to run inefficiently, which may turn on the check engine light.


Understanding these causes helps you identify whether the issue is something you can fix yourself or if professional help is needed.


Close-up view of a car dashboard showing the check engine light illuminated
Car dashboard with check engine light on

How to Diagnose the Problem


When the check engine light comes on, the first step is to diagnose the problem. Here’s how you can do it:


  1. Check the Gas Cap: Make sure the gas cap is tight and in good condition. If it was loose, tighten it and see if the light goes off after a few drives.

  2. Use an OBD-II Scanner: Most modern cars have an On-Board Diagnostics (OBD-II) port. You can buy or borrow a scanner to read the error codes stored in your vehicle’s computer.

  3. Interpret the Codes: The scanner will provide a code that corresponds to a specific issue. You can look up these codes online or in the scanner’s manual.

  4. Research the Problem: Once you know the code, research what it means and possible fixes. Some issues are simple, like replacing a sensor, while others may require a mechanic.

  5. Reset the Light: After addressing the problem, you can reset the check engine light using the scanner or by disconnecting the battery for a short time. If the light returns, further diagnosis is needed.


If you don’t have access to a scanner or prefer professional assistance, visiting a trusted auto repair shop is a good option. Funk Bros. Auto offers free scans!


Eye-level view of a mechanic using an OBD-II scanner on a car
Mechanic diagnosing car with OBD-II scanner

Is it Okay to Drive with the Check Engine Light On?


One of the most common questions is whether it’s safe to keep driving when the check engine light is on. The answer depends on the nature of the problem:


  • Steady Light: If the light is steady, it usually means a non-emergency issue. You can often continue driving but should get the car checked soon to avoid further damage.

  • Flashing Light: A flashing check engine light indicates a serious problem, such as a misfire that can damage the catalytic converter. In this case, stop driving immediately and seek professional help.

  • Additional Symptoms: If you notice other symptoms like strange noises, loss of power, or poor fuel economy, it’s best to have the vehicle inspected right away.


Ignoring the check engine light can lead to more expensive repairs down the road. When in doubt, err on the side of caution.


What to Do When the Check Engine Light Comes On


Here are practical steps to take when you see the check engine light:


  1. Don’t Panic: The light is a warning, not an immediate emergency in most cases.

  2. Check for Obvious Issues: Look for loose gas caps or other simple problems.

  3. Reduce Driving: Limit driving until you can diagnose or repair the issue.

  4. Schedule a Diagnostic Test: Visit a professional mechanic or use an OBD-II scanner to identify the problem.

  5. Follow Repair Recommendations: Address the issue promptly to avoid further damage.

  6. Keep Records: Document any repairs or diagnostics for future reference.


By following these steps, you can handle the situation calmly and effectively.


High angle view of a car parked at an auto repair shop
Car parked at auto repair shop for check engine light diagnosis

Preventing Check Engine Light Issues


Prevention is always better than cure. Here are some tips to reduce the chances of your check engine light coming on:


  • Regular Maintenance: Follow your vehicle’s maintenance schedule for oil changes, spark plug replacements, and other services.

  • Use Quality Fuel: Poor quality fuel can cause engine problems and sensor issues.

  • Check Gas Cap Regularly: Make sure the gas cap is secure after refueling.

  • Monitor Engine Performance: Pay attention to any changes in how your car runs.

  • Address Minor Issues Quickly: Don’t ignore small problems that could escalate.


Taking these steps can help keep your vehicle running smoothly and prevent unexpected check engine light alerts.



If you ever find yourself with the check engine light on, don’t hesitate to get a professional diagnosis. Funk Bros. auto offers free check engine light diagnosis! Early detection and repair can save you money and keep your vehicle safe on the road. Stay proactive and informed to enjoy a trouble-free driving experience.

 
 
 

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