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.
Four cylinder has two. Six cylinder has four.
There is 2 oxygen sensors on the 2002 Nissen altima
All O2 sensors are threaded into the exhaust system at various points.
around $1000 us
the part no. are 64,2387,79856
one is in the exhaust manifold, one goes into converter
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.