four
Assuming you have the V-6 engine, it has two downstream (after the cats) O2 sensors and two upstream (before the cats) Air/Fuel Ratio Sensors. So the answer to your question is two O2 sensors.
There are two oxygen sensors on a Nissan Sentra. This vehicle is an ultra-low emission car, thus needing only two oxygen sensors.
The 4 cylinder models have two oxygen sensors, and the V6 models have four oxygen sensors.
IN THE EXHAUST SYTEM meaning a 4 cylinder has 2 a v6 has 4. IN THE EXHAUST SYTEM meaning a 4 cylinder has 2 a v6 has 4.
The P0420 code on a 2005 Nissan Xterra indicates a problem with the catalytic converter's efficiency. To fix it, first, inspect the exhaust system for any leaks and check the oxygen sensors for proper operation. If the sensors are functioning but the code persists, the catalytic converter may need to be replaced, as it could be clogged or damaged. Additionally, ensure that the engine is running optimally with no other issues that could affect emissions.
Four cylinder has two. Six cylinder has four.
There is 2 oxygen sensors on the 2002 Nissen altima
around $1000 us
All O2 sensors are threaded into the exhaust system at various points.
One on a four cylinder, two on a six cylinder.
If you have a 4 cylinder engine, you will have two. On a 6 cylinder, you will have four.
one is in the exhaust manifold, one goes into converter