So i'm laying out all my wiring getting ready to drop a B18C1 into a '97 EX. The only wire I don't know what to with is actually not a wire yet and I don't know if I need to add one. #21 on plug C for the barometric sensor. What do I do with this guy? I managed to get an OBD2 P72 so that's the deal. Anyone know what I do with this?

 

The barometric pressure sensor is located inside the ECU, right on the circuit board. You should have no wire for that one, unless you got some old stuff from somewhere. They stopped using an external PA (barometric pressure) sensor in 1992.