your PCV valve is on your valve cover......this is your vapor managment hose.....your CHECK FUEL CAP will come on if the truck detects a leak in the line somewhere....thats why it took me forever to figure it out...my programmer was throwing the code as well..
no you don't turn it......like that hose should be disconnect from where my finger is pointing..you should be able to push the entire HOSE to the right and let it snap
My "Check Fuel Cap" came on a couple days ago. Cap was loose and I tightened it back up, took about 8mi before the warning went away...just a thought