This is the thread you want to look through:
http://www.peachparts.com/shopforum/showthread.php?t=107630
As far as dealing with Code 5... this is usually a plugged up EGR circuit. If you follow the 3-foot tube that snakes from the EGR valve to the intake manifold, the blockage is usually within the first few inches of the tube where it connects at the intake manifold. This is a bear to get at. Many people snake an old speedometer cable from the EGR end of the tube to ream out the blockage.