DTC P1154 O2 Sensor Circuit Range/Performance (Low) (Bank 2 Sensor 1)
WARNING: This page is about a different car, the 2006 Subaru Outback. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
For diagnostic procedure, refer to
DTC P1155 O2 SENSOR CIRCUIT RANGE/PERFORMANCE (HIGH) (BANK 2 SENSOR 1) , Diagnostic Procedure with Diagnostic Trouble Code (DTC).