HOW MANY OXYGEN SENSOR DOES MY CAR HAVE AND LOCATIONS

There should be only 2. There is a heated O2 sensor both before the catalytic converter and after. They are both mounted in the exhaust system.

The P0172 indicates the fuel mixture is too rich (too much gas). Check fuel pump pressure to assure the regulator is working.

The P0170 indicates a fuel trim malfunction. Fuel trim is the time the computer allows the injector to be open to inject fuel. If it is open too long, you will get a rich mixture.

The most common mistake people make is to replace the oxygen sensors when this problem comes up. Most commonly, there is a vacuum leak at the manifold which leans the fuel mixture and then the PCM over compensated providing too much fuel to the engine. Thus, the codes you are seeing. Also, a bad or faulty Mass Air Flow sensor can do the same.

Check these things before just replacing the oxygen sensors.

Joe