im running an 2006 hd with the lbz. The codes are po407 and 676. I have 32000 miles on it. upgrades include hypertech programer, s and b cold air intake and a magnaflow cat back 5inch stainless exhaust,and an fs2500 oil fiter. all upgrades have been on the truck for at least 10000 miles.I went to autozone today to checkout the codes thay couldnt tell me what the po676 was but thay handed me a little book that said the po407 was the egr valve or fuse or wet connector to the egr. I drive 100 miles a day to work. Ive had it throw a code when I stop for fuel{ with engine off } then get back on the road. I was told thats due to the presure in the tank it never did it around town.I just hookup the hypertech and erase it but these two worry me eny help will be aprichated thanks Gene Melow
throwing codes update well I took truck too chevy. the 676 code was #6 glow plug.while thay were in there thay checked the others found #s 1and 3 were weak so thay changed them also.The 407 code [egr] needed an ajustment.the code being thrown when Ifill up on long trips was due to a bad or weak fuel cap that alowed air to escap.hope this will help enyone else with these problems
