Check Engine Light Why the Gas Cap is a Common Cause

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Hi, I'm Mike from 1A Auto. I hope this how-to video helps you out, and next time you need parts for your vehicle, think of 1AAuto.com. Thanks.

If you get a check engine light after you've stopped for gas or filled up for gas, you're going to want to check your gas cap. We're showing a 2003 Nissan Altima here because that's the vehicle we were working on. You want to check your gas cap.

Obviously, the first thing is you want to check to see that you put your gas cap back into place and you put it on tight. If you did put your gas cap on tight, then you'll want to check for these codes. Have your check engine light scanned and if your car comes up with one of these codes, then what you have is an issue with the vacuum system in your tank. Your gas cap is actually designed to hold a certain amount of pressure, which is actually vacuum pressure. Your car has sensors to make sure that that level of pressure is maintained. When that level of pressure is not maintained, that's when it throws one of these codes.

If you're getting one of these codes, then the first thing you want to do is check your gas cap for a few common problems. One of the integral parts is the rubber seal. You can see we demonstrated here where a seal can get rolled over. This obviously causes a vacuum leak.

Next, we remove the seal. That can happen. A seal can break. The seal can fall off and be gone. That's obviously going to cause a vacuum leak and cause most trouble codes to go off. Here, you can see in about the one to two o'clock position, or the two to three o'clock position, there's a piece of gasket missing. Your gasket can get dry and brittle and break. It can also develop cracks. Those cracks develop leaks in the vacuum system.

Not all gas caps are the same. On the left, you can see a little larger diameter gas cap. Make sure that somebody didn't replace the gas cap or you didn't accidentally purchase an incorrect gas cap to put on your vehicle. If you do get a check engine light after you put fuel in your vehicle, check your gas cap. If you find a problem with it, obviously, a replacement from 1A Auto will fix you up.

If you diagnose it and you get one of those trouble codes, then a good suggestion is to try a new gas cap. It's an inexpensive and pretty easy fix.. Please feel free to call us toll free 888-844-3393. We're the company that's here for you on the internet and in person.

We hope this video helps you out. Brought to you by www.1AAuto.com, your source for quality replacement parts and the best service on the Internet. Please feel free to call us toll-free, 888-844-3393. We're the company that's here for you on the Internet and in person.