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Discussion Starter · #1 ·
Hey guys

My 02 Jeep Wrangler X is now giving me the code

PO442:
Evaporative Emission Control System Leak Detected (medium leak)

What do I need to do to fix this? What could be causing this? Thanks!!
 

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Check your gas cap - usually what happens is that the evap system pressurizes the fuel vapor management system to check for leaks, and if your cap isn't on good and tight, it'll detect a massive leak and throw that code.
 

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Discussion Starter · #3 ·
I got a locking gas cap when I first bought the Jeep about 6 months ago. Do you think I should replace that one?

What other things could be wrong to cause this code? Is it something I should worry about as far as damaging any vital engine parts? From what I know about auto repair in general, the evap system just has to do with pollution control.....
 

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2018 JLUR on tons and 40's.
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pry the o-ring off the gas cap and turn it over and re-install it. tighten the cap down and see if it cures your problem. The gas cap o-ring can flatten out after a period of time and cause a small evap leak. You will also have to reset the PCM to get rid of the code.
 

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WINNAR!!!!!!
2018 JLUR on tons and 40's.
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disconnect the power wire from the battery. Leave it off for a bit. I actually touch the power wire to the ground before I hook it back up. :)
 

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WINNAR!!!!!!
2018 JLUR on tons and 40's.
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you might fail inspection but it shouldn't hurt anything. Do you have the stock gas cap you could use to see if your new cap is the problem? If that doesn't work and is not your problem I will hunt through the FSM on the next possible solutions.
 

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Gas Cap

Yup. Gas Cap. With the fuel prices here in California, I decided to put a locking cap on. Took it to the dealer and that was the problem.
 

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Code 442...check all rubber hoses for cracking/leakage (make sure they are connected to to various portions of the evap system)....check for water infiltration into any of the lines (have you power washed engine compartment)...at top of gas tank where evap hose connects....check that gas tank hasn't wedged against body thereby causing a crack/leak in line (did you overtighten gas tank straps or "land" on a rock jamming top of gas tank against floor of jeep.
 

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Discussion Starter · #12 ·
I took the battery cables off and the code was gone for a few days, but it has reappeared. I checked some of the hoses and they look fine. Any other suggestions??
 

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under the hood, there sould be a diagram of the evap system. you need to go through all the hoses and vac lines. My dad had that code and after going through all the lines it ended up being a vac line on the manifold was off. put it back on reset the code and it never came back.
 

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Okay, please don't bite the newb. I've got my Haynes Manual in hand, and I'm ready to take on the world... or at least my 442 code. However, I'm looking at their diagrams and pictures... and descriptions... and I'll be damned if I can find the canister. HM says it should be on the passenger side fire wall, where I have a BIG open space... did I lose it? ;) Any help greatly appreciated.
 
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