I had the p0447 code evap emission control system vent circuit open. I checked the wiring above the charcoal canister and sure enough the yellow wire was corroded right inside a black wire connector that connected 3 yellow wires together. Before i fixed it I would erase the code and the check engine light would come back on right after I started the car. After I respliced the wires together and erased the code the check engine light didn't come back on after I started it. Thanks a lot for the very helpful pictures and info!