This code has been killing me for coming on 2 months now.. the MIL lamp is mostly on but sometimes it shuts off after i get a full tank of gas but then comes back on after about a few days.. i bought a new gas cap hoping the new gasket would seal up better since the stock one was shot.. that did nothing.. any suggestions on where i can trouble shoot? not trying to go to a shop and pay all the extra $$ if i can fix it myself.. hoping its just a hose a something.. thanks for the help

__________________
Louie F.

The leak detection pump is detecting a small leak somewhere. Have a look behind the LH rear wheel cover, there you will find the EVAP canister and several hoses. maybe one hose is in bad shape or loose. The line runs from there to the purge solenoid in the engine bay, so there are many places where a line can be shaved through.

__________________
Frank




JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
Monroe Reflex shocks /
Pirelli Scorpion ATR 245/65/17/
Transgo reprogramming shiftkit.

the leak detection pump is detecting what exactly that is leaking oil? fuel? coolant?

I have p0494 coming up giving me something up with that leak detection pump

__________________
\


00wj Red genIII projector head lights, K&N CAI. (more coming soon!)

thanks frango.. its been a rough winter here in jersery so maybe some salt got to the lines.. and violent p0456 is an evap code detecting a slight leak in gasoline fumes

__________________
Louie F.

Is P0494 not a "FAN SPEED LOW" code?
The P0456 code is indeed a leak detected somewhere in the EVAP system. That system catches the fuel vapors from the fuel tank and reroute them to the engine inlet to burn them off. The purge solenoid controls the flow of vapors (or in fact the PCM controls it by pulsing the purge solenoid)

__________________
Frank




JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
Monroe Reflex shocks /
Pirelli Scorpion ATR 245/65/17/
Transgo reprogramming shiftkit.

Have a smoke test done helps in locating leaks..........

I had the same code, and it was a couple of cracked lines going from the purge solenoid to "somewhere." I just replaced them with new lines (I think 1/4") and it has been all good.

__________________

look at all the lines near the intake manifold... look at the purge solenoid and follow the lines as far as you can. If you see any cracking in the end of the hose, replace the hose with bulk hose. The hose I have found to be causing the issue more often than not on the WJ is directly above the axle. A hard hose running from the front of the vehicle to the back of the vehicle goes to soft hose at that point and usually the hose is cracking at the buldge on the hard hose (the buldge to help keep the joint together). I have found there to be plenty of slack in that hose to cut the bad end off and just reconnect it.

Good luck!

Thanks everyone! tips are much appreciated

__________________
Louie F.

I read thru this complete thread and followed the hard lines back to the rear axle. Just above the rear axle I found the rubber hose connection to the forward going hard line. This rubber hose was a formed factory piece with cracks at the connection point. I spliced in a piece of rubber 3/8 hose using a hard piece of copper tubing. After what I believe was four successful key cycles, the code light went off and it appears the problem has been corrected at least for now. Yes, the gas cap can cause this problem too. I had already replaced the rubber hose pieces under the hood. They were the easiest ones first.
So just wanted to thank the last reply for directing me right to the problem.

no problem

I just got this code on my 05 WK, I haven't looked at it yet because there just hasn't been time to but are the hoses routed the same on the WK as the WJ?