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Could a Loose Gas Cap Be Causing Your Check Engine Light Problem?

It is only natural to become nervous when the check engine light in your car turns on. If this has never happened to you before, you may fear that you will not be able to make it home safely. Yet there are some causes of this car problem that are relatively minor to fix. Learn the relationship between your gas cap and the check engine light to troubleshoot a check engine light in your car.

Common Causes of a Check Engine Light

Among the many reasons that your car's check engine light turns on are:

  • Loose gas cap
  • Cracked or otherwise faulty gas cap
  • Worn spark plug or wire
  • Faulty oxygen sensor
  • Catalytic converter trouble
  • Faulty mass airflow sensor


Hopefully, knowing the common causes of a check engine light has made you feel relieved. Next time your check engine light comes on, pull the car over to the shoulder as soon as it is safe to do so.

If your car is smoking or making a unusual noise and the check engine light is on, it may indicate engine trouble. In this car, you would be wise to stop driving and arrange a tow to the mechanic.

Yet if the light comes on and your car is not smoking or making a unusual noise, why not take a minute to check the gas cap? Even if you are not experienced at car repair, you can quickly inspect the gas cap. You might be able to fix your problem without visiting your local auto shop, saving both time and money.

How to Check if Your Gas Cap is Loose


Open the gas cap door if required and get out of the car. If it is dark, take a flashlight with you. In order to check if the gas cap is cracked, you may need the extra light.
Look at the gas cap. Do you notice any cracks, chips, or tears in it? If so, a simple gas cap replacement may be able to solve your problem. It is a good idea to inspect the seal that is between the gas cap and the filler tube for any tears or cracking that could cause a vapor leak.

If you are satisfied that the gas cap is not damaged, fully install it into the filler tube. Then tighten the gas cap with your hand until you hear the cap click in place. If it does not click in place or is loose after clicking into place the cap needs to be replaced.

The check engine light should go off after you drive for several minutes if the light was caused by a loose gas cap.

Pay attention to the dashboard after the check engine light experience. If you find that the light keeps coming on, and goes off again once you tighten the gas cap, then your gas cap is too loose.

If you realized that your gas cap is faulty or loose, it is simple to order a replacement gas cap. When doing so, you must make sure the gas cap is suitable for your vehicle's make and model to ensure a tight fit.
Have you ever had the check engine light come on? If so, what caused it?