P0455 and P0442 Engine Codes -- Need Help!

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joshy0077

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Hey Folks,

Got a check engine light a couple weeks ago and took my car to autozone to get it checked out. Diagnostic machine read:


DTC (Codes)

P0455
EVAP Emission Control System Leak (Large)

DTC Pending (Codes)

P0442
EVAP Emission Control System Leak (Small)

Any ideas what could be wrong? Autozone tech said it was probably a loose gas cap, but seeing as how its been a few weeks and not gone away, I'm sort of concerned. Just had the Jeep E-checked in late November and there did not seem to be any issues with gas cap pressure.

Appreciate the help!
 

dnm45227

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the code will be stored in the computer for 250 cycles of the ignition, or until cleared by a diagnostic tool/powered down by removing the battery cable.

try disconnecting the neg battery terminal for at least 10 min, then see if the light comes back.
 

2003KJ

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The 0442 has a good chance of being a lose gas cap....most common issue among small evap leak engine codes.

The fact that you're throwing one for a large leak also, makes me think otherwise however...

What year is your KJ, and how many miles do you have on her?
 

Marlon_JB2

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Sounds like a crack in the evap hose somewhere... the question is where... :-k If it was just P0442, then it probably would be the gas cap.
 

joshy0077

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The fact that you're throwing one for a large leak also, makes me think otherwise however...

What year is your KJ, and how many miles do you have on her?

My libby is a 2k2 with about 45,000 miles on her. Hope this is nothing serious (Aeh) Think it's worth taking to the dealer?
 

2003KJ

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joshy0077 said:
The fact that you're throwing one for a large leak also, makes me think otherwise however...

What year is your KJ, and how many miles do you have on her?

My libby is a 2k2 with about 45,000 miles on her. Hope this is nothing serious (Aeh) Think it's worth taking to the dealer?

to eliminate the obvious, you could start by replacing the gas cap. It probably will not solve it, but it's an idea, and they're pretty cheap (i know the locking one I got for my KJ a couple of years ago cost me about $10 and change at Napa).

Next I would start tracing hoses, especially going from the gas tank to the engine. Look for deep cracks, or any other signs that it might be losing pressure.

i've got a copy of the 2002 Factory Service Manual that would explain the evap. system in much more detail if you're interested. PM me and we'll talk about it. O:)
 

sprsonic

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joshy0077 said:
The fact that you're throwing one for a large leak also, makes me think otherwise however...

What year is your KJ, and how many miles do you have on her?

My libby is a 2k2 with about 45,000 miles on her. Hope this is nothing serious (Aeh) Think it's worth taking to the dealer?

check for a cracked rubber hose in front of your fuel tank, there is three hoses that take a crap on 02-03 kj's. just replaced with bulk hose.
 

Red02Liberty

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I've got the same message, only the P0442, anything to worry about? I'll try changing the gas cap, I disconnected the battery cable and it temporarily went away, but came back :( I have 180,000 miles on my 02 KJ
 

CHUD

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Next I would start tracing hoses, especially going from the gas tank to the engine. Look for deep cracks, or any other signs that it might be losing pressure.

That P0455 can be a ****** to nail down. Had the same issue with my 02 WJ. Gas cap was not it. I just waited until inspection time (car won't pass inspection if throwing a code) and had the shop check into possible cause. They could not find anything either. Ended up having to do a smoke test, which uncovered the cause as a hose degradation in the system. Smoke test was expensive though. Hope you don't have to drop that kind of gap on a smoke test.
 

timmer

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I had both of those codes and it was a cracked hose high-lighted below (7):

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Edited to add: I initially had the small leak code which became a large leak code.

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Not pretty but it worked...
 
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The Fixer

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Looks like the same hose that failed on my wife's '03 at 28K miles. I changed it and the code hasn't come back in almost a year.
 

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