The diagnostic code P2271 OBDII refers to the Oxygen (O2) sensor number 2 on bank 1. This sensor is intended to verify the proper operation of the Catalytic Converter (TWC). The Catalytic Converter or Catalyst reduces the tailpipe emissions.
When this fault code is stored, it is because the Powertrain Control Module (PCM) has detected that the signal from O2 sensor number 2 is stuck in rich, in other words, there is a significant lack of air in the exhaust.