Basically this means that the oxygen sensor downstream of the catalytic converter on bank 2 (passenger side) is detecting that the converter is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.
The catalytic converter is no longer functioning properly
An oxygen sensor is not reading (functioning) properly
There is an exhaust leak
Next step is to measure the voltage at the oxygen sensor on Bank 2 (the passenger side rear sensor, or the sensor after the converter). The voltage should be low and steady (~200mV, depends on the vehicle). If the voltage varies (e.g. 100mV to 600mV) then it's time to replace the catalytic converter. In fact, it would be a good idea to test each oxygen O2 sensor while you're at it.