BDFHYK Oxygen Sensor Upstream O2, Compatible with Subaru 2000-2002 Forester Impreza Legacy Outback 2.5L H4, 17018, 15230, 22791AA00A Replacement 1PCS

17018 Upstream Oxygen Sensor for 2000–2002 Subaru 2.5L Models

This BDFHYK upstream oxygen sensor is an OE-style aftermarket replacement for selected 2000–2002 Subaru Forester, Impreza, Legacy, and Outback 2.5L H4 applications that match 17018, 15230, or 22791AA00A. For a Subaru Forester O2 sensor replacement or Subaru O2 sensor replacement, verify the exact engine, upstream exhaust position, original part number, connector, and lead routing before ordering.

17018 Subaru Forester, Impreza, Legacy, and Outback Fitment

Some Legacy and Outback applications can vary by transmission or calibration. Confirm the original sensor reference and physical configuration even when the model year and engine match.

17018 Subaru Upstream Oxygen Sensor Specifications

• Position: Upstream
• Engine: 2.5L H4 gasoline
• Interchange references: 17018; 15230; 22791AA00A
• Package: 1 sensor

Diagnosing a 17018 Subaru O2 Sensor Before Replacement

A stored fault code or Check Engine Light does not prove that the upstream oxygen sensor has failed. Inspect the connector, harness routing, heater power and ground where applicable, exhaust leaks, and related engine-running conditions before replacing parts. Confirm the sensor location from vehicle-specific service information because similar-looking sensors may be used in different positions.

How to know which O2 sensor is bad starts with identifying the stored code and the affected exhaust location, then checking wiring, connector condition, exhaust leaks, fuel control, and engine-running faults. Do not replace an upstream sensor from a code description alone.

Installing the 17018 Subaru Forester O2 Sensor Replacement

• Allow the exhaust system to cool completely before removal.
• Compare the old and replacement sensors before installation, including the OE reference, connector, lead routing, and physical configuration.
• Use an O2 sensor socket or suitable wrench; avoid impact tools on the sensor.
• Start the sensor by hand to reduce the risk of cross-threading the exhaust bung.
• Use anti-seize only when permitted by the sensor instructions, and keep compounds away from the sensing element.
• Route the harness away from hot exhaust surfaces, sharp edges, and moving parts, then tighten to the vehicle-specific specification.