Rear Oxygen Sensor: Removal

Disconnect the ground cable from battery.
Lift up the vehicle.
Remove the under cover. Ref. to EXTERIOR/INTERIOR TRIM>Front Under Cover>REMOVAL .
Disconnect the connector on the rear oxygen sensor from the engine harness.

Fig 1: Locating Rear Oxygen Sensor Connector
Courtesy of SUBARU OF AMERICA, INC.
Apply spray-type lubricant (004301003) 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 2: Locating Rear Oxygen Sensor

Courtesy of SUBARU OF AMERICA, INC.