Ford P0156 OBD-II Trouble Code Definition: P0156 HO2S22 Sensor Range/Performance Condition P0156 Ford OBD-II Trouble CodeDescription: OBD Trouble Code P0156 O2 Sensor Circuit What does the code mean? OBD-ii Code P0156 definition: The o2 (oxygen) sensors measure oxygen content in the exhaust. The PCM (powertrain control module) then uses this information to regulate fuel injector pulse. […]