Diagnostic code reader says EGR valve stuck open.

What is your question?

Before I put my van in the shop my "check engine soon" light came on. I didn't know at the time what for, I was already going to put it in the shop for a complete rebuild. Just had the engine rebuilt, idles smooth as silk but the "check engine soon" light came back on within 10 miles of picking up my van. I read the codes with a scanner and it said "EGR valve open". The guy at O'Reilly's said that if that was why the light came on before it went in the shop and they didn't clear the codes that may be the issue. He suggested I clear the code and see if the light comes back on. Is this okay?