I have code p0140 0xygen sensor 2, bank 1. Is this the front o2 closer to the bumper or the rear o2 by the firewall? I keep finding different answers to this. I have the o2 sensor in my hand right now, I'm ready to unscrew them as we speak. -1999 Maxima SE-L 5mt

 

sensor 2 is the rear sensor.

 

YES! I just guessed and replaced the rear one! I reset the ecu, I've driven about 40 miles so far ran some erins today, Light hasn't come back on yet, so hopefully its fixed