I have to replace both my O2 sensors. The chiltons repari manual says "O2 SENSORS ARE LOCATED IN THE EXAUST MANIFOLD AND MAY ALSO BE LOCATED IN THE EXAUST SYSTEM NEAR THE CATALYTIC CONVERTER". All I wanna know is where the hell these things are so I can replace them. My question is:
1) Is the exaust manifold right next to that "FLEX PIPE"?
2) Is the catalytic converter right under the drivers seat and is called a "THREE WAY CTALYST"? Also....when it says, disconnect the electrical harness.....is it the "other end of what the O2 sensor connects to"? Please help me out with this guys. Thanks.

 

Exhaust gases pass from the cylinder heads through the exhaust manifolds, the Y-pipe, the three-way catalytic converter, the resonator, the exhaust pipe, and the muffler. The flex pipe is part of the Y-pipe. If your Maxima is OBD-2 compliant it has three Oxygen Sensors: one in each exhaust manifold and one just downstream of the "cat".

The Haynes manual has better pictures of the Oxygen Sensor locations. I consider the Haynes book better than Chilton for most repair procedures.

Your dealer might replace those Oxygen Sensors at no cost, even though your car is off warranty. It doesn't hurt to ask.

 

Why are you replacing your sensors? Did you get a check engine code or something else. Just curious.