Where is o2 sensor located on a 2000 Nissan Sentra?

On a 2000 Nissan Sentra, the oxygen (O2) sensors are typically located in two places: one is positioned in the exhaust manifold before the catalytic converter (upstream O2 sensor), and the other is located after the catalytic converter (downstream O2 sensor). To access them, you may need to raise the vehicle and work underneath, as they are threaded into the exhaust system. Be sure to disconnect the electrical connectors before attempting to remove the sensors.