DTC P013B O2 Sensor Slow Response - Lean To Rich (Bank 1 Sensor 2)
WARNING: This page is about a different car, the 2012 Subaru Forester. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
For the diagnostic procedure, refer to DTC P013A O2 SENSOR SLOW RESPONSE - RICH TO LEAN (BANK 1 SENSOR 2)