Backup Battery

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.

Disconnect the ground terminal from battery sensor. < Ref. to BATTERY , NOTE, Repair Contents. >
Remove the data communication module. < Ref. to DATA COMMUNICATION MODULE , REMOVAL, Data Communication Module. >
Remove the backup battery.
1. Remove the screws, and then remove the battery cover.
  Preparation tool:
  
  TORX® T10
2. Disconnect the connector and remove the backup battery.
  
  Fig 1: Locating Backup Battery Screw And Connector
  Courtesy of SUBARU OF AMERICA, INC.