While I had my manifold off I thought I'd try to learn as much about it as I could, and I started looking for potential problems. I came across the nipple for the vacuum line that leads to this valve, it was rusty. So I decided to look into it a little bit and discovered it was plugged up with old oil. The name is vague so I have no idea what it does, what problems was it causing me that I did not know about? Potential engine codes it could have brought up? I had 4, feedback system for o2 sensor, Intake Air thermostat, Solenoid Valve turbo pre-control, and Solenoid valve wastegate control.

 

Look at this diagram and tell us what solenoid it was for:

 

It is for the "C" solenoid.