misterskin

2001 Cherokee. I pretty much knew I had jinxed myself when I posted that the gas cap had fixed the problem. The codes popped up again today about the time I hit 1/2 tank of gas on my gauge. I live down a gravel road too and the light, even before, seemed to only come on when the fuel level was at 1/2 tank or below AND I drove pretty hard down this ragady *** washboarded road.
The damn thing does not seem to run any different, there is nothing noticable that I can tell, so really the light and not knowing whats setting it off is just getting more annoying than anything. Any suggestions on what else I could try. Anyone have a vacuum diagram? Hell, I'm up for anything except dumping a bunch of money in it.

P0442 (M) Evap Leak Monitor Medium Leak Detected A small leak has been detected in the evaporative system.

P0455 (M) Evap Leak Monitor Large Leak Detected A large leak has been detected in the evaporative system.

Thanks.....again.

E28hfd

I have a 2000 XJ. When I first got it and would fill up with gas I would top off the tank (keep filling till it was over full) I would get the same code. Once I stopped filling past the point of the handle clicking off the codes stopped. Just a thought.

GreenClassic

Somebody told me the evap system is what relieves pressure from the gas tank. This is supposed to keep the gas tank from ballooning, and possibly rupturing.

The evap system is supposed to take the excess vapors and burn them, so they are not released into the environment. With those codes, it sounds like some of the gas vapors are getting released rather than burned.

Just my guess.