P0401 - EGR Insuff Flow Code on 2001 Ford Escape

Check engine light is on. Just tuned up, plugs, filter, fluid levels ok. Diagnostic code shows P0401. What does this mean? What are probable fixes?

Asked by for the 2001 Ford Escape
here is an article about EGR codes, specifically the P0401, which is an EGR System fault for low flow.
1 more answer
check vsv solenoid.