My check engine light keeps coming on. But it only comes on when I fill up my gas tank. As long a there is less than 3/4 tank its ok. I have had the 02 sensor change about a year ago. It was about $300.00 at the dealer to get it changed. If I can help it I'll stay away from the dealer in the future. Any advise what it could be the problem.

 

The check engine light can mean a lot of things, you can goto Autozone and they'll pull the codes for free.

 

Try adjusting the gas cap. Maybe loosen it up to see if the light goes out. As the previous post said, you should get the codes pulled.

 

Please put your vehicle year and engine in your profile. This will help in providing you with an answer. While it is likely a 97, you can have three different engines.

 

I have a 97 Explorer, 4.0L EFI V6 SOHC. About 2 years ago I had the fuel tank pressure sensor and the DPFE (?) sensor and hoses replaced trying to find out what the problem was. Now the light is back on again.

 

Just came back from AutoZone where they checked my truck with the code tester. The code P0446 came up. EVAP system fuel tank pressure (FTP) sensor fault. Sounds like the same problem I had before. Any ideas why it keeps coming up. Is there any way to correct the problem without taking it back to the dealer($).

 

I would find the tank electrical connector and unplug it, then reconnect it. Just in case there is a bad electrical contact. Bad sensor is uncommon and located in the tank. Sensor is 3 wire and you could probably check it. Dropping the tank is not fun or cheap. Evap leaks are more common and usually involve the solenoid above the spare tire that gets water damage.

 

Just a Question......Have you replaced your gas cap. If you have a bad seal on the cap, it wont hold pressure causing your check engine light to come on with that same code.
Just my $0.02

 

Yes I did replace the cap. I think I may get another cap just to see if that is tha problem. A few dollars on a new cap will not hurt. Thanks for your 2 cents.

 

Have you tried disconnecting the battery for 5 minutes to clear the code? If so, does the light still come back on?

 

I have disconnected the battery before when the light came on. But after a few miles it would just come back on. This time I have not done it yet.

 

Where is and what does the solenoid above the spare tire that may have some water damage look like. I think thats the answer to why my light is on.