Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSSUBARU2016LEGACY 2.5IREPAIR AND DIAGNOSISENGINE PERFORMANCEFUEL DELIVERYFUEL INJECTION SYSTEM (H4DO)FRONT OXYGEN (A/F) SENSORINSTALLATION

2016 Subaru Legacy 2.5i

Front Oxygen (A/F) Sensor: Installation

2016 Subaru Legacy 2.5iSECTION Installation

CAUTION: If lubricant is spilt over the exhaust pipe, wipe it off with cloth to avoid emission of smoke or causing a fire.

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
Install the front oxygen (A/F) sensor.
Tightening torque:

21 N.m (2.1 kgf-m, 15.5 ft-lb)

Fig 1: Locating Front Oxygen (A/F) Sensor
Courtesy of SUBARU OF AMERICA, INC.
Lift up the vehicle.
Connect the front oxygen (A/F) sensor connector, and secure the front oxygen (A/F) sensor harness by using the clip.

Fig 2: Locating Front Oxygen (A/F) Sensor
Courtesy of SUBARU OF AMERICA, INC.
Install the under cover. < Ref. to INSTALLATION , Front Under Cover. >
Lower the vehicle.
Connect the ground terminal to battery sensor. < Ref. to BATTERY , NOTE, Repair Contents. >

RENDER: 1.0x

NO RELATED

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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.