Join Date: Jan 2007
Location: Sharpsville, PA
Own a Commander?: Yes
Model year: 2006
Trim Package: Sport
Power-Train: 4.7L V-8
If 4WD - system: QD-II
Current Mileage: 85000
I am currently in the same boat as you. I have the P0456 for about 2 years now and occasionally get the "Check Gas Cap" display message. I can clear the code and sometimes get a couple of days before it comes back. My mechanic has replaced the canister and I'm pretty sure done some other things as well (like new gas cap). Every time the CEL will come on and it's P0456. Last time I had it in the shop, he told me the fuel filler neck was not making contact with the seal on the gas gap and he tried other gas caps with no luck. He asked if i ever had the fuel filler neck replaced, etc. I bought mine new and never had did anything to it. He told me $300 to replace the fuel filler neck. I told him I would live with the CEL for now.
On a side note, the jeep will sometimes drop into a lower RPM than normal idle and i have had the jeep flat out stall. I am not sure if an evap leak could cause such of symptom. I have recently run a bottle of fuel cleaner in the gas tank as i thought maybe it might be something fuel system related.
2006 65th Anniversary Edition Commander (Black/Grey)
Specs: 4.7 V8, 4x4
Toys: Bel Vector 995
Mods: Steering Wheel Controls, removed airbox resonator,
Bilstein 5100, 245/70/17 Cooper AT/3