2001 RAV 4 - O2 sensors

I bought a used 2001 RAV4. Imjmediately started getting service engine light.

Fault code comes up PO161 - O2 sensor heater circuit malfunction (bank 2 Sensor 2.

Anyone know which one this is and where it is located? Any poictures or good directions would help. And has anyone used a generic sensor on one of these RAV 4s?

thanks for any advice.

OK, I have the problem solved other than if a generic will work or not.
It appears several are on the market however.

Looking at the front of the car:
Bank 1 sensor 1 is top right before cat
Bank 2 sensor 1 is top left before cat
Bank 1 sensor 2 is bottom right after cat
Bank 2 sensor 2 is bottom left after cat.

Hope this helps some one else later on.