2000 jeep Cherokee 4.0 4x4
Cell light comes on after about 40miles. Code P0456 I've tried a different gas cap. That didn't fix it I've chased a few lines. Not having much luck any insight .

Thanks in advance.

 

The light won't turn off instantly, especially with the EVAP system. The best way to check for an EVAP leak is with a smoke machine. I have seen the purge solenoid stick open and the leak detection pump cause a leak.

 

First question. What brand gas cap. Second, did you reset the code or at least drive 3 times with 50 miles of driving per trip. When the ignorant gas attendant doesn't twist my cap on and I throw a CEL, it takes a good amount of time for the CEL to go away unless I clear the code. Also, I like using Mopar OE parts. And here is a site you can use just in case it isn't the gas cap, there's lines to trace too. http://www.jeepforum.com/forum/f11/p0456-1109285/

 

You beat me lol

 

Dealer cap and yes I cleared it also silicone a few spots I thought might have been leaking drove it to advance reset the code drove five miles parked then drive to work 37miles parked then drive home about half way the light came on again.

 

Time to start checking lines at the charcoal canister. Also at the evap purge valve under the hood.

 

Smoke tests for hours it feels . not finding any leaks
How do I know if its the purge valve just replace it.