I found this on the problems forum, but I couldnt get the link to copy over so here is what they said.
your HFCM has a lot of crap in it that has been seperated and is causing your WIF light to trip. Do as somone said and remove the front cover. The bolts on it there are 4 one in each corner and are 25torx bits. The gasket Part # is 9276 (CG-810) and is $34. And if you want to replace the WIF sensor that is Part # 9C264 $37. And as mentioned it wont take longer than 30mins to do and that is if you work extremely slow. But after you get it cleaned and new gasket installed tightened up. I would open the drain valve and turn key on till you start seeing fuel come out then turn key off and then close the valve. Then cycle the key as if you just changed your fuel filters. I did mine 12 times because I kept hearing air being purged. And don't be scared if you start your truck and it dies. It just means you still have air trapped in your lines. Do the purge 6 more times and you should be good after that. I left mine running for about 10 minutes after it started up and continued running to ensure all the air was out of the system.
I hope this helps,