1996 Chevy Corsica - O2 sensor locations

I got a P0140 the other day and scanner says that bank 1, sensor 2 has no activity. Is bank 1, sensor 2 located behind the engine, on the exhaust manifold or along the tailpipe? Those are the only O2 sensors that I can see. Autozone diagrams are generic as it shows 4 locations for a typical V6. This is a V6 3.1L VIN M. I went ahead and bought a Bosch Universal -4 wire #15732 as the clerk recommended. Would this part work for either locations, how many does this car have and where is bank 1, sensor 2? Thank you!