egr solenoid on 1990 Acura Legend

What is an egr solenoid and do u have any price ranges for this in my zip?
Thank you.
P.S. I really have a 1989 Legend

Asked by for the 1990 Acura Legend
The solenoid is located in the black plastic box at the back of the engine compartment it enables the EGR to operate only when the EGR is supposed to receive vacuum to open the EGR valve. It will take .7 hours to replace and will probably not be in stock at any Acura dealer. My guess is the valve will be $100. but I show no cost as it is a dealer only item. (1989)