Tonight I cleaned my EGR. I was super cautious and the nut holding it onto the bracket was a pain (I removed the bracket and that caused me to freak out. Loose gaskets and whatnot, but it went back together ok. What is the bracket holding on?)

As I've been getting errors from this forever and just getting into repair seriously, and accidentally thought 2-4-1 was AMM (uh.. whoops) not EGR, I held off on cleaning it until I got some other basic things fixed.

Point: my temp sensor for my EGR is missing. The wires are sheared off at the sensor and nowhere to be found. There is also no wiring harness that is disconnected, but-

There are two identical temp sensor looking items: one _in_ the EGR and one in the tube running from the EGR to the intake manifold. Which is which? Has my car been given a double sensor by its PO?

Currently, the sensor in the EGR is attached to a 2-prong plastic plug like a ton of the sensors on this car are. Is this the right one? I'm getting 2-4-1 (EGR flow too low) and 4-1-3 (EGR temp sensor error or missing).
I'm kinda thinking that the error for a missing temp sensor and the chopped wiring are related. Any suggestions?

Also, does anyone know what that black item attached by the mount for the EGR does? It has two cylinders, one larger than the other (the larger closer to the firewall) and feeds into the block. There don't appear to be any electrical connectors to or from it.

-Will
--
1990 740 Turbo, on its way to stock specs, maybe beyond