Front Oxygen (A/F) Sensor: Installation

2004 Subaru Outback Base, 4D Wagon, EJ251, StandardSECTION Installation
  1. Before installing front oxygen (A/F) sensor, apply anti-seize compound only to threaded portion of front oxygen (A/F) sensor to make the next removal easier.
    1. Anti-seize compound:  SS-30 by JET LUBE
    CAUTION: Never apply anti-seize compound to protector of front oxygen (A/F) sensor. 
  2. Install front oxygen (A/F) sensor.
    1. Tightening torque:  21 N.m (2.1 kgf-m, 15.2 ft-lb)
    Fig 1: Installing Front Oxygen (A/F) Sensor
    G00898833Courtesy of SUBARU OF AMERICA, INC.
  3. Lower the vehicle.
  4. Connect connector of front oxygen (A/F) sensor.
    Fig 2: Connecting Connector Of Front Oxygen (A/F) Sensor
    G00898834Courtesy of SUBARU OF AMERICA, INC.
  5. Connect battery ground cable.
    Fig 3: Connecting Battery Ground Cable
    G00898835Courtesy of SUBARU OF AMERICA, INC.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.