rear heated O2 sensor

I have a 1996 240sx 5sp and need help replacing my rear heated oxygen sensor. Sounds easy, but I can't find it. Where on the car is it located?
I found two toward the front of the car, one near the engine and the other on the exhaust pipe on drivers side. I called the nearest nissan dealership and they couldn't even tell me how many O2 sensor are on my car. I am hoping someone out there can help me out.
Thanks.

since yours is a 96 it runs an OBD-II ecu

OBD-II cars generally have atleast 2 o2 sensors, and in these positions..

one before catalytic converter, one after catalytic converter


the one after the cat is probably what you can't find.

im not 100% certain of this, but its a good place to check. Most cars if not all that run OBD-II have that setup of o2 sensors, its just how the ecu works and senses all this shit, i don't know if its that way on a OBD-II 240sx but it probably is.

obd-ii has a lot more sensors, wires, and the computer is more controlling of how engine runs... this is why I, and many other tuners... HATE OBD-II

thanks for your help. So besides the two O2 sensors I found toward the front of the car. There are more toward the rear? I looked under there but didn't see anything that looked like the ones in the front. I agree with you about the computer coding. I liked it better when cars didn't have computers and you could just look under the hood and see what was broken!

I thought there was only two o2 sensors. I mean s13 only has 1, and I thought s14 only had 2.

I know there are two for sure, but when I ordered a rear oxygen sensor the one I received had a plug with 4 prongs, but the sensor on the car had a plug with 3 prongs. So I ordered another sensor with a 3 prong plug, but this sensor was to big in diameter to fit in the hole. I guess I will have to give up and pay the high price and take it in to the dealer. I just hate to for what should be a quick, simple, cheap fix.

maybe they sold you the wrong ones. or just go to the dealer and buy the o2 sensor from them and install it yourself.