Error Codes P0442/P0455 are back

Jeep Grand Cherokee 2002 4.7l V8 116k miles

I recently posted thread
http://groups.google.com/group/rec.a...96a45 43ceb7e
here.

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

axel wrote:
> Jeep Grand Cherokee 2002 4.7l V8 116k miles

> 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?

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.

> 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?

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.


--
DougW

The DTC's say you have a medium or large leak in the emissions system.
You need to check all of your lines between the carbon canister and the
engine. the lines will run from the canister to the purge valve that will be
located under the hood on the left side. One line from the purge valve runs
over to the throttle body. More that likely you will have a hose split on
the end creating a medium or large leak.
I believe that a large leak is only .0040" and that is pretty small. You
will also have a line running from the canister to the fuel tank. Check
your fuel cap. Wipe the debris away from the tank lip and look to see if
the seal looks good.
I work on quite a few jeeps in our
dealership(http://www.boltonchryslerdodgejeep.com/) and we find that after
about 4 or 5 years the emission hoses start to crack on the ends and some of
the hoses turn green. I don't know why but I do wonder where the hose
comes from. I replace the lines with fuel line hose. Holds up better.
Hope this helps.
Ken
"DougW" > wrote in message
...
> axel wrote:
>> Jeep Grand Cherokee 2002 4.7l V8 116k miles
>
>> 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?
>
> 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.
>
>> 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?
>
> 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.
>
>
> --
> DougW
>