Walker 350-64022 Oxygen Sensor - Upstream

Walker 350-64022 Oxygen Sensor Overview

Walker Products 350-64022 is a heated upstream oxygen sensor built as a specific-fit OE-style replacement for select Subaru and Acura applications. It is engineered to provide the ECU with the feedback needed for fuel control and emissions monitoring on vehicles such as the Subaru Baja, Forester, Impreza, Legacy, Outback, and Acura EL.

Walker Products Aftermarket focuses on engine management and oxygen/air-fuel sensors for application-specific fitment, and this part number is matched to the correct mounting position and connector style for the listed vehicles.

Key Features

• Heated oxygen sensor for upstream placement
• Specific fit design for direct application matching
• 4-wire configuration with female connector
• Threaded mounting type with 18.0 mm thread diameter
• 19.61 in. wiring harness length and 23.15 in. overall length
• Radiused polygon connector shape for vehicle-specific connection
• Walker Products part number 350-64022

Detailed Product Description

The Walker Products 350-64022 oxygen sensor is designed for upstream exhaust monitoring on 2003-2006 Subaru Baja, 2003-2004 Subaru Forester, 2003-2004 Subaru Impreza, 2003-2004 Subaru Legacy, 2003-2004 Subaru Outback, and 2004-2005 Acura EL applications. As a heated sensor, it helps the engine management system maintain accurate feedback during warm-up and normal operation, supporting proper air-fuel control and emissions performance.

This Walker Products Aftermarket sensor line is built around application-specific replacement parts, so the connector, harness length, and threaded mounting style are matched to the intended vehicle position. If the original sensor has failed, the ECU may store fault codes and the vehicle may show poor running behavior, higher fuel use, increased exhaust emissions, or a malfunction indicator light. Part number 350-64022 is intended for the upstream oxygen sensor location on the listed vehicles.

What This Oxygen Sensor Helps Address

• Check engine light related to upstream oxygen sensor faults
• Rough engine operation caused by incorrect exhaust feedback
• Increased fuel consumption from inaccurate air-fuel control
• Elevated exhaust emissions from a failing sensor signal
• Stored ECU fault codes tied to the oxygen sensor circuit

Installation Notes and Tips

Confirm the vehicle year, make, model, and upstream sensor position before ordering. For best results, inspect the sensor wiring harness and connector for heat damage, corrosion, or physical wear before installation. The sensor uses a threaded mount and a 4-wire female connector, so the replacement should be matched to the original connector style and harness routing on the vehicle.

Fits 2003-2006 Subaru Baja, upstream; fits 2003-2004 Subaru Forester, upstream; fits 2003-2004 Subaru Impreza, upstream; fits 2003-2004 Subaru Legacy, upstream; fits 2003-2004 Subaru Outback, upstream; fits 2004-2005 Acura EL, upstream.

Quality Assurance

Walker Products has supplied engine management and fuel system components since 1946 and operates as an ISO 9001/TS 16949 certified company. The 350-64022 oxygen sensor is manufactured for the specified application and position to support the diagnostic feedback expected by the ECU.