P0443 Evap Code Help

I have been searching threads to help solve my p0443 code but havent found much of a solution. So here is the problem:

I bought a 1997 Jeep Cherokee and replaced the engine/transmission/computer from a 1998 Cherokee. I ran the Jeep for a couple times without any codes and all the sudden the p0443 code pops up. I check all the vacuum lines and purge solenoid, they are all fine. Replaced the gas cap- still the code. I reset the codes, however the code pops up immediately after starting the engine which makes no sense since you would think that after the computer is reset, it would take the evap system some time to send a code back to the computer. I am stumped on what i should do. Does anyone have any ideas where the problem may lie. Thanks

Sounds like a major evap leak. Check the hard plastic and rubber inbetween lines from the evap purge all the way to the gas tank. I had a hell of a time tracking down a P0455 code on my '01 and found a cracked rubber line down right below the steering shaft. You could also take it to a shop and have them do a smoke test on it.

otc leaktamer time

yeah, i am thinking either a leak by the gas tank or a short in the wiring. my aux fan wont come on either so it could be the wiring. i hate to waste money paying my mechanic to look for the short, since i dont know anything about electrical systems.

Does the fan come on w/the defrost or A/C? U could try jumping the fan from the battery itself to make sure the fan itself works. Could also hook up a toggle through a relay to the E. fan.

no the fan does not come on in the defrost or a/c setting. I directly connected it to the battery and it will come on so the motor works. i have read posts regarding the relay but like i said before, i have no experience with electrical problems. i have tried putting other relays in the pdc but it still wont come on. i know that the refrigerant has leaked out of the system but shouldnt it still come on in the defrost setting.

If there isn't enough refigerant in the system the fan will not come on w/the defrost. Try w/the engine running and the A/C or defrost on jumping the pigtail on the high pressure side(or could be the low. Forgot) It's on the silver evap canister. Jumping that with a paper clip or something of the like should lock the A/C clutch and turn on the fan.

would any of you know whether 1998 xj has a different fuel system setup by the fuel tank from a 1997 xj. It seems to me that the problem might lie with a missing canister.