01 XJ Small Evap Leak P0456

Hello, For about the past two months my check engine light is being thrown with a P0456 code for a small evap leak. I can clear the code & it will take sometimes a day or two for it to come back on or it has went for about two weeks one time before it came back on. I have replaced my gas cap with a brand new mopar one, I can feel & sometimes hear the plurge valve clicking so I believe it is working, & I have checked out all the lines & fittings from the charcoal canister up into the engine compartment & they all are pushed in tight & the lines look good, no cracks, splits, or cuts. My Jeep still starts & runs fine, I just don`t know what or were else to check out to fix this problem. My Jeep`s Specs are:

2001 Jeep Cherokee Limited
4.0 I6
AW4 Auto
NP-231 4X4
Loaded with about every option for that year.

Thank You

By your description and the fact that it takes a while to set the code again, the leak is probably quite small. Yes, a faulty gas cap can cause this but replacing it with a mopar cap has pretty safely ruled that out.

My guess is that you have a small leak somewhere in the evap. system that you missed during the inspection, which is common because it's very difficult to visually and physically check the entire system out effectively without some testing.

Which is where I'm going next. Many shops can perform a "smoke test" where smoke is introduced into the evap. system and then the search is on to see where the smoke comes out to determine root cause. Not real expensive but may set you back $100-$150 or so.

If you continue to struggle with finding the problem, I'd just get this test run.

If you can get your hands on a smoke machine I would smoke it!

Joshooha said:

If you can get your hands on a smoke machine I would smoke it!

Click to expand...

Party store, school theatrical department, cheap old stoogie?