Hey guys o have a 2004.5 common rail iv bin having the p1222 code and I think I found the problem I was geting ready to change out the fca and was noticed the a line going from the top of the cp3 back to the the filter housing was leeking at the threaded connection I talked to the previous owner (1 of them) and the guy befor him did (the high flow upgrade) what seal it’s supposed to be in that threaded fitting I found a peace of gasket maker sticking out of the side of it