I was wondering if somebody might be able to tell me what some of these codes i am pulling mean. i always have a PO401 EGR (undertstand that one) which keeps my light on so i try to check with the power pup every couple weeks for anything else. Last time i checked 2-3 weeks ago I pulled PO128 unknown and PO381 Glow Plug Malfunction, cleared them. I checked it again today and got P=026 unknown and P=064 unknown. I would love to know what all of the unknown ones mean and also why different ones come and go. Also, i only get the PO401 until i pull the fuses, then i get other stuff. thanx in advance.