All,

My van one day had the Service Engine Soon light come on and the engine started to knock while at idle, so I went to autozone and had them scan the computer and check for codes. It had a P0401 code. I checked this website and decided to do poormans troubleshooting. I bought a EGR valve for $60 and went home. After removing/replacing it, both problems went away and the van is running strong. Hope this helps!