Evaporative Emission System Leak-Help

[dchadjohnson]

Okay so for a while now I've been getting these recurring CELs and I'm hoping someone can help without having to take this to the dealer for expensive diagnostics and repairs.

The codes I am getting are:
P0456 Evaporative emission system leak detected (very small leak)
P0457 Evaporative emission system leak detected (fuel cap loose/off)

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Repair attempt #1 was to replace the fuel cap. No joy

Repair attempt #2 was to replace the vapor canister emission purge valve solenoid up front by the battery. I also checked the hoses up front and don't see any cracks or breaks in the hard narrow plastic lines.

Sooo...my next thought is to replace the Evaporative System Leak Detection Pump (aka Evaporative System
Integrity Module Detector) - the white plastic thing circled in red in the picture below. Is that a pain to replace? It looks like there is just an electrical connector and either a twist off or pull/push connection.

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I also thought it would be good to replace the two hoses indicated by the yellow arrows in case there is a pinhole leak somewhere - I bought some 3/8" fuel line, but that seems way too small for the 3 marked fittings. Does anybody know what size hose I should get?

I also recently filled up with gas and the Jeep failed to start until the fuel pump had run for a bit - I'm hoping this isn't a sign of a bad fuel pump, as I don't really want to drop the fuel tank. Seems like I'm getting new problems every month lately

Thanks for the advice everyone!

 

[profdlp]

I am going through the same thing. You are actually a step ahead of me. I am at the point where I may just start yanking random hoses in the parking lot at an auto store and replace them one by one, then move on from there if need be.

 

[tommudd]

Many of the hoses are prone to small cracks which can cause the issues , even though you can not see where they are cracked
also did you use a Mopar gas cap ? Many of the aftermarket just do not seal as well as the Mopar ones do

 

[dchadjohnson]

Many of the hoses are prone to small cracks which can cause the issues , even though you can not see where they are cracked
also did you use a Mopar gas cap ? Many of the aftermarket just do not seal as well as the Mopar ones do

yep I guess I am just looking for guidance as to the proper size hose to use - the 3/8" fuel line i bought looks way too small, and I seem to recall reading that perhaps they have two differently sized ends?

And yes, OEM Mopar gas cap

 

[adamkrz]

Best to do a smoke test - otherwise you end up changing up lots of good parts, My 04 ended up needing a seal on top of the fuel tank.

 

[MarksmanAkula]

"Sooo...my next thought is to replace the Evaporative System Leak Detection Pump (aka Evaporative System
Integrity Module Detector) - the white plastic thing circled in red in the picture below. Is that a pain to replace? It looks like there is just an electrical connector and either a twist off or pull/push connection."



I was hunting down an EVAP leak for weeks on our liberty. But it ended up being the solenoid valve you described as the white box in the picture.

Two shop smoke checks couldn't find that.

The electrical connection to it had corroded and eaten a hole in the side of the valve.

VERY easy part to replace, just make sure you either get a new gasket with it, or reuse your old one when you pop it off a quarter turn, you'll see it on the threads.

 

[clw426]

I had the same codes. replaced the leak detection pump ,also known as an ESIM, no more codes.

 

[Doing10to20]

I've had the same issue for years ,did the smoke test replaced some lines still comes on,passed emissions...we settled on its gotta be the pump,but it somehow passed emissions so the hell with it I said lol..good luck