codes P0442 P0455

EZLiberty · **Joined:** Sat Aug 08, 2009 9:46 pm **Posts:** 84

Hello, this is My first post I hope it is on the right forum.

I have this vehicle (2002 Jeep liberty 3.7l auto) almost 1 year now and had some transmission work done by the dealer. Soon after it came back to Me the engine light was ON (Again :evil:

) and I put My own scanner on it and the P0442 code was there I cleared it and put the stock cap ON the tank since I installed a keyed cap from the local auto parts store but the code came back and then another code (P0455) showed on the screen and I read some hoses could be bad but I looked under the fuel tank and most hoses look like new or in good condition (never replaced before) so I don't want to start pulling this apart to find out it is a common problem. Since the mech did tranny work here before the code appeared is it possible someone would know if there is a vacuum hose in that area and causing this codes.

Thank You in advance.

rickm · **Posted:** Fri Nov 06, 2009 3:47 am

isn't there a vacuum hose diagram under your hood? Why not follow that to trace the vacuum lines that are associated with fuel vapor recovery around the charcol canister.

Diggerfreek · **Posted:** Fri Nov 06, 2009 4:10 am

Moving to the correct section :wink:

EZLiberty · **Joined:** Sat Aug 08, 2009 9:46 pm **Posts:** 84

I didn't know there is a diagram in the hood, I check it out thank You.

Thank You for moving it.

EZLiberty · **Joined:** Sat Aug 08, 2009 9:46 pm **Posts:** 84

I found a couple hoses that where cracked so I replaced them but the code will come back so there is still a leak somewhere, this is I believe affecting My fuel mileage now which is btw low already.

Have anyone experienced this before, please let Me know I will use the jeep for a trip and I'd like it to be in good stable condition.

Thank You.

EZLiberty · **Joined:** Sat Aug 08, 2009 9:46 pm **Posts:** 84

Anyone?

ZERO6 · **Posted:** Thu Jan 14, 2010 10:04 am

Maybe this site will help.
http://www.obd-codes.com/p0455
http://www.obd-codes.com/p0442

EZLiberty · **Joined:** Sat Aug 08, 2009 9:46 pm **Posts:** 84

I checked the fuel hoses and found a section that could need replacing so I replaced it but it all look good. Now I'm not familiar with gasoline engines so I need a little extra help with this. The engine is always humming, this normal or could this be related to the vacuum leak described on the code page? Also the MPG on the jeep is very low now, used to get maybe 240 miles to a tank and last time I filled I got 180 miles so something isn't right here.

Hope with a little more detail someone can give Me a tip to get this fixed. Thank You.

harsh20 · **Posted:** Sat Feb 06, 2010 12:35 am

have you inspected the seal on the cap?
crawl under and inspect the filler neck on the gas tank for a crack.
the charcoal canister above the rearend.
there are two rubber hoses on the firewall. these two fail the majority of the time.
the other area is on top of the gas tank. the hoses can slip off where they connect there.
it takes time and patience to trace these.
if you just can't find it have a half tank of fuel and take it to the dealer or a mechanic who can run a smoke test. minimum of 105.00 bucks at the dealer but local mechanic rates are around 50 to 55 dollars per hour.
not sure about the hum you mentioned because it a vacuum leak is a high pitch squeal sound type sound.
the leak will affect your mileage.

JeepinJarhead03 · **Posted:** Sat Feb 06, 2010 12:47 am

the hum is probably the fuel pump, only just now noticing it because you usually don't notice things like that unless you're looking for a problem

if the hum is under the hood it may be one of the primary vac hoses near the master cyl that are not connected, or loose, or cracked, check all the large vac hoses that go to and from the engine to the master cyl, those will make a hum, similar to some plastic wrap stuck in a vacuum cleaner

democedes · **Joined:** Thu Feb 04, 2010 2:58 pm **Posts:** 40

Had something similar with my 03 Renegade, Engine light on, they checked code, dont know what ones it threw but it was related to the vacuum system and apparently gas cover. After 5 different visits and a new pump in the gas tank they found a vacuum hose off and replaced the air filter, havent had an issue with it since.

codes P0442 P0455

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