2019 engine code p2271

Bank1 sensor2 is the "downstream" O2 sensor under the car near the secondary catalytic converter. The primary catalytic converter is welded to the exhaust headers in the engine compartment. If your fuel mixture is too rich it sets off that DTC and there are several things that can cause that including problems with the upstream O2 sensor, MAF sensor, MAP sensor (which Toyota calls the "Vacuum Sensor"), disconnected vacuum hoses (the ECM enriches fuel mixture to compensate), faulty stuck open fuel injectors. Did you get any other DTCs? Many guys would try to replace the upstream O2 sensor (mounted on top of the exhaust headers) with an OEM part. This may not cure the issue though if your original sensor did not cause the code. If the issue is sticky injectors, have you been using cheap gas? You should use only Top Tier. You could try running a couple bottles of Techron through the tank.