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Home >> Subaru >> 2015 >> WRX STI >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Fuel Injection System (STI) >> Front Oxygen (A/F) Sensor >> Removal
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Front Oxygen (A/F) Sensor: Removal

  1. Disconnect the ground cable from battery.
  2. Disconnect the connector from the front oxygen (A/F) sensor, and remove the clip (A) holding the return hose and front oxygen (A/F) sensor harness.
    Fig 1: Locating Front Oxygen (A/F) Sensor Harness Connector
    G10264866Courtesy of SUBARU OF AMERICA, INC.
  3. Remove the clips (A) holding the front oxygen (A/F) sensor harness to the engine harness stay.
    Fig 2: Identifying Front Oxygen (A/F) Sensor Harness Clips
    G08538814Courtesy of SUBARU OF AMERICA, INC.
  4. Lift up the vehicle.
  5. Remove the under cover. <Ref. to REMOVAL , Front Under Cover.>
  6. Apply spray-type lubricant to the threaded portion of front oxygen (A/F) sensor, and leave it for one minute or more.
  7. 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: Locating Front Oxygen (A/F) Sensor
    G08538815Courtesy of SUBARU OF AMERICA, INC.
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