Fault Code P2425

Hi all,

Hoping someone can help with a fault code problem that I have. My engine management light is on and I have used a fault code reader to obtain the fault code P2425. This code is "EGR Cooler valve / Open" Not much info on web. I removed and inspected EGR valve which was a bit coked up inside but the plunger was moving OK. I cleaned this and replaced. From what I can tell, the EGR and cleaner are controlled from the N75 vacuum distributer on the bulkhead. I can see no electrical conections in the area of the EGR valve. The only symptoms other than the engine management light are a significant drop in fuel economy. I was easily getting an average of about 45mpg but since the fault code has been present i struggle to get out of the 30's. Any suggestions would be welcome.