headache2000

I have a 2000 GMC Safari (same as the Chevy Astro) a few months ago I replaced the fuel pump. immediately after installing the new fuel pump (when I started it up for the 1st time) the SES light came on. I checked for DTC's and it was P1404 Exhaust Gas Recirculation Error (EGR number 2) I have an AutoXray 5000 Scanner and I am capable of turning off the SES light. The light will come back on after driving approximately 5 miles. Since the Black wire and Gray wire from the fuel pump sender unit are interconnected with the black wire from the EGR Valve I checked for loose or damaged wires at the fuel pump wire harness connector, I also cleaned the ground connection and did a continuity check of the wires from the fuel pump harness connector all the way to the VCM and everything checked out OK. I also checked the continuity of each of the 5 wires at the EGR Valve from the EGR valve connector all the way back to the VCM and everything checked out OK. Since the IAT and MAP sensors are also tied into the common black wire I checked these and they are also OK. I did replace the EGR Valve with no change. I no longer get the P1404 DTC but now I get the P0404 DTC. I'm lost at what to do next. Any suggestions? I know there is a TSB out for the SES and DTC's P1404 & P0404 but this did not come out until the 2002 model year.