Front Oxygen (A/F) Sensor: Removal

Set the vehicle on a lift.
Disconnect the ground cable from battery.

Fig 1: Disconnecting Ground Cable From Battery
Courtesy of SUBARU OF AMERICA, INC.
Remove the air intake duct. Refer to REMOVAL , Air Intake Duct.
Remove the clip fastening the harness and disconnect the front oxygen (A/F) sensor connector.

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

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