DTC P015A: O2 Sensor Delayed Response - Rich To Lean (Bank 1 Sensor 1)
WARNING: This page is about a different car, the 2014 Subaru XV Crosstrek. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
For the diagnostic procedure, refer to DTC P014C. < Ref. to
DTC P014C O2 SENSOR SLOW RESPONSE - RICH TO LEAN (BANK 1 SENSOR 1) , Diagnostic Procedure with Diagnostic Trouble Code (DTC).>