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Home >> Subaru >> 2017 >> Outback 2.5i >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Fuel Injection System (H4DO) >> Front Oxygen (A/F) Sensor >> Installation
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Front Oxygen (A/F) Sensor: Installation

CAUTION: If lubricant is spilt over the exhaust pipe, wipe it off with cloth to avoid emission of smoke or causing a fire.
  1. Before installing front oxygen (A/F) sensor, apply anti-seize compound only to the threaded portion of front oxygen (A/F) sensor to make the next removal easier.
    CAUTION: Never apply anti-seize compound to the protector of front oxygen (A/F) sensor.

    Anti-seize compound: 

    NEVER-SEEZ NSN, JET LUBE SS-30 or equivalent 

  2. Install the front oxygen (A/F) sensor.

    Tightening torque: 

    21 N.m (2.1 kgf-m, 15.5 ft-lb) 

    Fig 1: Identifying Front Oxygen Sensor
    G10262198Courtesy of SUBARU OF AMERICA, INC.
  3. Lift up the vehicle.
  4. Connect the front oxygen (A/F) sensor connector, and secure the front oxygen (A/F) sensor harness by using the clip.
    Fig 2: Identifying Front And Rear Oxygen Sensor Connectors And Clip
    G11565995Courtesy of SUBARU OF AMERICA, INC.
  5. Install the under cover. Ref. to INSTALLATION , Front Under Cover.
  6. Lower the vehicle.
  7. Connect the ground terminal to battery sensor. Ref. to BATTERY