Rear Oxygen Sensor: Removal

Disconnect the ground cable from battery.

Fig 1: Disconnecting Ground Cable From Battery
Courtesy of SUBARU OF AMERICA, INC.
Remove the air intake duct. Ref. to REMOVAL , Air Intake Duct.
Remove the clips (C) fastening the harness and disconnect the rear oxygen sensor connector (B).

Fig 2: Identifying Front Oxygen (A/F) Sensor Connector, Rear Oxygen Sensor Connector And Harness Clip
Courtesy of SUBARU OF AMERICA, INC.
Lift up the vehicle.
Remove the under cover. Ref. to REMOVAL , Front Under Cover.
Apply spray-type lubricant to the threaded portion of rear oxygen sensor, and leave it for one minute or more.
Remove the rear oxygen sensor.
CAUTION: When removing the rear oxygen sensor, wait until exhaust pipe cools, otherwise it will damage the exhaust pipe.

Fig 3: Identifying Front Oxygen (A/F) Sensor And Rear Oxygen Sensor
Courtesy of SUBARU OF AMERICA, INC.