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Check Fuel Cap + Very Small EVAP Leak Troubleshooting

keithcroshaw

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So I've seen a bit of information about this.
Of course a couple of months after my basic warranty is done my CEL comes on after a trip of "check fuel cap" warnings.
Of course I've checked the fuel caps, I even replaced the fuel cap now.
"oh you should get the OEM one", seems like a PITA to find ATM, I don't mind trying again, but I honestly don't think that's the problem.

My BlueDriver OBD adapter wouldn't pair with my phone anymore, I haven't needed it in so long I didn't know it stopped working.
Just got my OBDLink MX+, wanted to make sure that was actually the code it was throwing P0456.
I checked the purge valve located above the engine, which is really convenient.
One side had a little bit of of push to it I noticed.
This part seems like it'd be easy to replace, I don't see any obvious cracks in the hoses or plastic, but without a smoke test it would be hard to tell.

I tried to reset the codes incase my new cap and purge valve squeezing where enough, but they didn't seem to clear. It says permanent codes. Are those the type that you need to drive X amount of miles before they go away?

I really don't want a repair bill already for a 2022 vehicle, so any tips would be appreciated.
TIA.
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Lost1wing

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You can't clear the permanent code. It will pass a self test and clear on it's own. You can only clear a pending or active code. Clearing an active code should extinguish the check engine light. If you don't see a check engine light but you still see a pending code, keep troubleshooting.
 
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Janster

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Just a note - and you’re probably already ā€˜aware’ of this, but some might not…..

Never over-fill your gas tank! When the pump clicks off (stops pumping), don’t keep squeezing more gas in.

Why? overfilling the gas tank can allow gas to get into charcoal canister and/or other emissions parts causing error codes & expensive repairs.

Apparently, my brother-n-law wasn’t aware of this. He bought a used Porsche Mecan a little over a year ago. It sat at a local shop for a couple months - they couldn’t fix it (aftermarket parts & availability). He moved it to the Porsche dealer a month ago….. still waiting on OEM parts (backordered). šŸ™„
 

Trollboogie

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I had the same problem on my wife's 2018 JL. I replaced the cap ( OEM ) and was still getting the small evap code. I got a rag and put some WD-40 on it. Wiped the cap O-ring and the fuel fill neck where it seals. It has been a couple of months now and the code is gone.
 
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keithcroshaw

keithcroshaw

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That negative value looks like the purge valve sensor is dead. One’s in the mail.
Jeep Gladiator Check Fuel Cap + Very Small EVAP Leak Troubleshooting IMG_1109
 

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Lost1wing

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I'm sure you have tried, but sometimes just pulling the connector off and putting it back on will wake things up. It's free!

My neighbor had a similar issue. His ended up being a twig pulled a wire out of the plug. It broke the lock on the connector. I was able to push the pin back in but it kept giving the same code for a leak. A new connector fixed the leak code.
 
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keithcroshaw

keithcroshaw

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I'm sure you have tried, but sometimes just pulling the connector off and putting it back on will wake things up. It's free!

My neighbor had a similar issue. His ended up being a twig pulled a wire out of the plug. It broke the lock on the connector. I was able to push the pin back in but it kept giving the same code for a leak. A new connector fixed the leak code.
I guess I could return it if that’s the case. But a $40 part vs hundreds at the dealer is hard to pass up.
My remote start is disabled due to CEL.
It’s freakin cold.
I’m goin for replacement lol.
 

Lost1wing

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I guess I could return it if that’s the case. But a $40 part vs hundreds at the dealer is hard to pass up.
My remote start is disabled due to CEL.
It’s freakin cold.
I’m goin for replacement lol.
I get it! I'm not a fan of anything below 40f.
 

Alaska-HWY JK

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The twig pull the wire from the E-SIM not purge valve right?
 
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keithcroshaw

keithcroshaw

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An update, the "Genuine Mopar" purge valve from Amazon (was same price as rock auto and free shipping... I know, I know... The original has a horse and says continental, the "genuine" has a =V= symbol) did seem to make the active and pending codes clearable.
CEL gone.
There's still permanent codes and the "check gas cap" warnings keep coming up.
I have a long drive into the office tomorrow.
Fingers crossed that clears it all out.
At least I can remote start in the morning. phwew.

Just got done clearing the ice off, need to cover it with tarp or something next time, the bed rack with softopper underneath is no fun, plus the windshield sprayers were painfully iced over.
 

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Alaska-HWY JK

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So did your drive clear the CEL and gas cap alarm? I’ve got the same thing going on. Where to start though, gas cap, eSIM or purge valve? I know its not a battery issue, they were replaced last summer.
 
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keithcroshaw

keithcroshaw

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It was the purge valve that let me clear the CEL. The check fuel cap light is still on and the permanent codes are still on. I don’t know how long it can take to clear.
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