Check Power Steering Control Module
WARNING: This page is about a different car, the 2016 Subaru Outback and 2016 Subaru Legacy. However, it is still accessible from the selected car via links, so may be relevant.
Check for the electric power steering diagnostic trouble codes. If the diagnostic trouble code is detected, perform the diagnosis. < Ref. to BASIC DIAGNOSTIC PROCEDURE . >
Replace the steering gear box with a new part if necessary.