Error Codes P0442/P0455 are back

Jeep Grand Cherokee 2002 4.7l V8 116k miles

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As described I fixed the one hose that was clearly broken and caused the hissing noise I was hearing. I cleared the codes and everything was good for a day or so but then the codes came back. I reset them one more time but again after two days or so they are back.

I may replace the gas cap next but after that where do I start to determine what is causing the trouble codes? When I replaced the one hose I noticed that the hoses that are part of the pump systems in that LR fender area all look brittle and either one could be the problem potentially based on their condition. Do I just replace them one at the time or is there something I con do to detect where the leak actually is? Also, somebody here was saying the hoses in the engine compartment could also be the problem. In what area are they around the engine, meaning which ones am I looking for?

Any pointers are appreciated. Axel

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axel
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If they are brittle and the replacement is inexpensive I'd just replace them.

Usually you can run the engine and spray a can of carb cleaner around the hoses. If one sucks it in the engine will stammer a bit. Also seen this done with a propane torch (unlit of course) Same effect when it gets sucked in.

I just go over every hose I can find. The hardlines can have a problem where they are joined with those flexible rubber boots. Also at the bends.

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DougW

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BULLDOG

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