I recently replaced the EGR valve on my wife's 1999 Honda Odyssey. I took it to the auto parts store and they did the diagnostic test. I bought new EGR and put it on. I reset the check engine light by disconnecting the battery cable. This lasted just a short while and the light came back on. I bought a scan tool and reset it with that. A few miles down the road the check engine light came back on. It is still coding for the EGR valve. Did I get a bad EGR? I did notice on the replacement EGR, the port (opening) wasn't as large as the original EGR.