Walker 250-54058 Oxygen Sensor - Upstream

Walker OE Heated Oxygen Sensor for Subaru

Walker Products OE oxygen sensor 250-54058 is a specific-fit, heated upstream sensor engineered for direct replacement in select Subaru and Saab applications. It is built to deliver the diagnostic feedback the ECU expects, helping maintain proper fuel control and emissions performance.

Key Features

• Heated oxygen sensor for upstream placement
• Specific-fit design for direct application matching
• 4-wire configuration with 20-gauge wiring
• Threaded mounting with 18.0 mm thread diameter
• Radiused polygon male connector for vehicle-specific connection
• Wiring harness length: 29.06 in.; overall length: 32.6 in.

Product Details

Walker Products OE focuses on original-equipment-style replacement sensors for engine management systems. Part number 250-54058 is designed for upstream oxygen sensor locations and is listed for vehicles including the Subaru WRX STI, Forester, Impreza, Legacy, Outback, Baja, and Saab 9-2X. Fits 2015-2020 Subaru WRX STI, Upstream; Fits 2004-2010 Subaru Forester, Upstream; Fits 2004-2008 Subaru Impreza, Upstream; Fits 2005-2007 Subaru Legacy, Upstream; Fits 2005-2007 Subaru Outback, Upstream; Fits 2006 Saab 9-2X, Upstream; Fits 2005 Subaru Baja, Upstream. This part cross-references no listed aftermarket part numbers in the provided data.

What It Helps Address

• Check engine light related to upstream oxygen sensor faults
• Poor fuel economy caused by inaccurate exhaust feedback
• Rough engine operation from incorrect air-fuel readings
• Elevated exhaust emissions from a failing sensor
• Stored ECU fault codes tied to sensor performance

Installation Notes

Verify the connector shape, wire count, thread diameter, and sensor position before installation. Inspect the sensor wiring harness and connector for heat damage, abrasion, or corrosion, since damaged wiring can shorten sensor life and affect ECU feedback. Confirm the replacement is for the upstream location on the listed Subaru and Saab applications before service.

Quality Assurance

Walker Products has supplied engine management and fuel system components since 1946 and operates as an ISO 9001 / TS 16949 certified manufacturer. The OE product line is built around application-specific fitment and diagnostic signal requirements for modern engine control systems.