DTC P0136: Heated Oxygen Sensor Circuit Fault: Notes
WARNING: This page is about a different car, the 2002 Lexus RX 300. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Bank No. 1 refers to bank which includes cylinder No. 1. Heated oxygen sensor No. 2 refers to sensor furthest away from engine block.