bank 1 location

This picture shows the bank 1 location.

Bank 1 is next to the firewall bank 2 is next to the radiator. Bank 1 refers to cyl. 1 side and bank 2 refers to cyl. 2 side.
Bank 1 sensor 1 is just below the exhaust manifold on the back side of the engine towards the fire wall. It's easiest to get to the sensor from underneith the car.