To monitor the exhaust oxygen content present in the engine, the PCM uses the data provided by the Oxygen Sensors (O2). With this input data, the effectiveness of the Catalyst (TWC) is also checked.
Once the engine is warmed up, the PCM checks the operation of the O2 sensor circuit. When the DTC P2241 OBDII code is set, the PCM has found that the Oxygen Sensor 1 control circuit on bank 2 has a voltage below the allowable limit.