<!-- from fixya rte -->O2 SENSOR FUSE LOCATION IN A NISSAN MAXMIA - 2000 Nissan Maxima

SOURCE: location of a o2 sensor 2001 nissan maxima

bank 1 refers to the side of the engine that #1 cylinder is on , and sensor 2 refers to downstream , after the catalytic converter. , this link shows bank 1 on a 2001 nissan maxima V6 being on the firewall side . if you had a 4 cylinder it would be downstream after the catalytic converter .

http://www.autozone.com/N,26200242/shopping/specsSelect.htm

SOURCE: O2 Sensor Bank 1 on a 2004 Nissan Pathfinder

ON THE EXAHST

SOURCE: 1996 Nissan Maxima o2 Sensor Location

check out www.maxima.org

SOURCE: I have a 2003 Nissan Sentra SE-R Spec V. o2 sensor location?!?1

theres always one on the intake manifold working its way down to catalytic convertor is the oxygen sensor 1 heater circuit(pre cat conv) signal while terminal #25 is oxygen sensor 2 heater circuit (post cat conv)

SOURCE: where is o2 sensor designated bank 1 sensor 1

Bank 1 is the side Cyclinder 1 in on, sensor 1 is befor cat converter. I think 7/8 box wrench, as in difficulty that depends on what in in the way.