code p1406 1997 venture
 

I have a 1997 venture that has recently failed emissions. The egr valve has been replaced but code p1406 keeps coming back. Is it possible that the dpfe downstream hose is clogged? Are there any more causes of this problem? Are the any more hoses that can be cleaned or replaced? I really need to get it back on the road any help would be much appreciated, thanx.