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Discussion Starter · #1 ·
I recently bought a 98 TJ 4.0 and the check engine light came on. When I went to Autozone and got them to read the codes, P0455 and P0463 came up. They cleared the codes and sent me on my way saying that it might be the gas cap or a leak somewhere. I then tried to get it emissions tested and it failed. The gas cap is on tight, does it need replacing? Also, is there a leak in the system somewhere that would need fixing to pass emissions? Any help on the codes is much appreciated.
 

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The 463 is a fuel level sensor failure code. Did you test the gas cap? You can examine the O-ring around the cap for damage as well as testing the pressure valve by sucking on the valve body on the inside of the cap. If it doesn't snap shut and only allow air to enter the tank, it needs replacement.
 

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P0455 Evaporative Emission Control System Leak Detected (gross leak)
P0463 Fuel Level Sensor Circuit High Input

Type these numbers (one at a time) into google search and you will find a ton of information regarding each code with possible causes, solutions. and steps to determine
what is wrong.
 

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Discussion Starter · #4 ·
Thanks guys. It sounds like all I need to do for both problems is to replace the gas cap. I'll give that a try and see if the code pops back up again. If it doesn't, hopefully I'll be able to pass emissions!

A ton of information came up in my search about the EVAP system. What parts are these and how do I locate them?
 

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Thanks guys. It sounds like all I need to do for both problems is to replace the gas cap. I'll give that a try and see if the code pops back up again. If it doesn't, hopefully I'll be able to pass emissions!

A ton of information came up in my search about the EVAP system. What parts are these and how do I locate them?
I'm not sure how you came to believe that a defective fuel cap could be the root of both these codes. Did I miss something here? I'm not even sure if you bothered to test the cap to see if it is defective.
 

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Did you fail cause your monitors weren't completed? Here in NY on 97 & newer the state computer hooks up to the car via the dlc connecter and checks to see if your monitors were passed. If you had a check engine light on and codes were cleared, all of your monitors would have been reset. And if you went to your emissions test before they were run the vehicle would fail even though everything was working right.
 

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I had the Major Evap leak code...
This is what I didi:
Replaced the gas cap NG
Replaced the Charcoal Canister NG
The Solenoid that drives it NG
While off roading--I smelled gas fumes .
My shop retested the gas tank under pressure..came up with a bad fuel pump and seal.

Replaced that whole unit and its seal and it worked...Good!

Hope you have better luck then I did..I went with an OEM fuel pump...coast about $400.

Good Luck.
 

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Discussion Starter · #8 ·
I'm not sure how you came to believe that a defective fuel cap could be the root of both these codes. Did I miss something here? I'm not even sure if you bothered to test the cap to see if it is defective.
I came to that conclusion because you and others said that the cap could be the source of the problem. I also tested the cap and the O-Rings are whole and intact but when performing the suck test, and getting a mouth full of fuel, it did not snap shut as expected.

Cameljoe, I did not know about the completing the monitors. Now that you mention it, and after a quick google search, it makes sense that it didn't pass emissions in CT after clearing the check engine light. I'm going to need to drive it around a little bit more to get the monitors completed.

Muddyspokes, I hope that I don't have to go to the great lengths that you went to to fix the problem. This Jeep just recently passed NH inspection and is now having problems with the CT emissions. What did you do after you replaced each component to see if it solved the problem?


Thanks all for your continued help.
 

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Bulletins were checked. Chrysler has a series of components they recommend changing out for this error code. We replaced the components-reset the codes and tried driving the 50 miles to cycle through. When the Check Engine returned-we moved onto the next item on the list. Of course the gas cap is the easiest and cheapest to replace...
If you smell any fumes----around the fuel tank-that just might be the culprit.
When it was taken down-I could easily see the stains from the long term leak..I'm glad its done.
If you have a shop that can perform a leak test do it..it may point directly to the problem. The canister and solenoid are like 60 and 40 bucks and quick replacement.
You can also visually check under neath the gas tank for any stains-look around the filler hose too.
Keep us posted.
 

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Discussion Starter · #10 ·
Quick Update. I replaced the fuel cap and drove about 100 miles to make sure that the check engine light would not come back on afterwards and it did not. I just passed emissions yesterday with this fix.

Thanks for all the help.
 

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I came to that conclusion because you and others said that the cap could be the source of the problem. I also tested the cap and the O-Rings are whole and intact but when performing the suck test, and getting a mouth full of fuel, it did not snap shut as expected.
Ah, you DID perform the Suck-Test and it failed. It is beneficial during the diagnostic process when test results liks this are posted. See ya 'round, kid.
 

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Congrats on the pass. I'm glad to hear that it didn't cost you too much to get it cleared up. Best rule of thumb in repairs "Cheapest First"
 
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