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 radiator main fan motor assembly. Refer to RADIATOR SUB FAN AND FAN MOTOR .
Disconnect the connector from the rear oxygen sensor, and remove the clip (A) holding the rear oxygen sensor harness.

Fig 2: Locating Rear Oxygen Sensor Connector
Courtesy of SUBARU OF AMERICA, INC.
Apply spray-type lubricant to the threaded portion of rear oxygen sensor, and leave it for one minute or more.
Remove the rear oxygen (A/F) sensor by using a sensor socket.

CAUTION: When removing the rear oxygen sensor, wait until exhaust pipe cools, otherwise it will damage the exhaust pipe.

Fig 3: Locating Rear Oxygen Sensor

Courtesy of SUBARU OF AMERICA, INC.