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Home >> Subaru >> 2017 >> WRX STI >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Fuel Injection System (2.5L) >> Rear Oxygen Sensor >> Installation
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Rear Oxygen Sensor: Installation

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

    Anti-seize compound: 

    NEVER-SEEZ NSN, JET LUBE SS-30 or 

    equivalent 

  2. Install the rear oxygen sensor.

    Tightening torque: 

    21 N.m (2.1 kgf-m, 15.5 ft-lb) 

    Fig 1: Rear Oxygen Sensor
    G08538823Courtesy of SUBARU OF AMERICA, INC.
  3. Connect the connector to the rear oxygen sensor, and hold the rear oxygen sensor harness with the clip (A).
    Fig 2: Locating Rear Oxygen Sensor Harness Clip
    G08538822Courtesy of SUBARU OF AMERICA, INC.
  4. Install the transmission under cover.

    Tightening torque: 

    18 N.m (1.8 kgf-m, 13.3 ft-lb) 

  5. Lower the vehicle.
  6. Connect the battery ground terminal.