Oldbeaver (ha!), no, I haven't actually tried to do anything with this sensor. But I still intend to.
That being said, if you look at the wiring diagram
in the first post of this thread, you will see the sensor in question. It is labeled #64. I'm no electrical engineer, but it looks like the center wire is 12V in, the one on the left is some fixed voltage out (through a trim pot - reference signal?) and the one in the right it's a variable voltage out (through a rheostat).
Edit: apparently I'm close in my assumptions except that the RPS varies current, not voltage. Still unsure of the total range but EGR function varies from 100% at 530 mA to 0% at 370 mA. Amperage decreases as rack travel increases. Source:
FSM section on EGR function.
If that info helps you, please share your findings with me! Otherwise, I intend to eventually put 12V through a spare pump I have laying around and try to get it to tell me something.