Walker 350-64044 Oxygen Sensor - Upstream or Upstream Left

Walker 350-64044 Oxygen Sensor Overview

Walker Products 350-64044 is a heated, specific-fit oxygen sensor engineered as an OE replacement for select Subaru Legacy, Subaru Outback, and Toyota Sienna applications. It is built for the upstream position and is designed to provide the ECU with the feedback needed for proper fuel control and emissions monitoring.

Walker Products Aftermarket focuses on engine management and oxygen/air-fuel sensors for exact application fitment, including the correct mounting position and connector style. The 350-64044 follows that approach for vehicles that require an upstream sensor with a threaded mount and 4-wire heated design.

Key Features

• Part number: 350-64044
• Heated oxygen sensor for upstream placement
• Specific fit application for direct vehicle matching
• 4-wire design with 20-gauge wiring
• Radiused polygon male connector
• Threaded mounting type with 18.0 mm thread diameter
• Wiring harness length: 6.42
• Overall length: 9.96

Vehicle Fitment

• Fits 2021-2024 Subaru Legacy, upstream.
• Fits 2021-2024 Subaru Outback, upstream.
• Fits 2020 Subaru Legacy, upstream. Bank 1 Sensor 1 needs an upstream oxygen sensor.
• Fits 2020 Subaru Legacy, upstream. Front oxygen sensor compatible with various vehicle models.
• Fits 2020 Subaru Outback, upstream. Bank 1 Sensor 1 needs an upstream oxygen sensor.
• Fits 2020 Subaru Outback, upstream. Front oxygen sensor compatible with various vehicle models.
• Fits 2015-2019 Subaru Legacy, upstream left.
• Fits 2015-2019 Subaru Outback, upstream left.
• Fits 2011-2012 Toyota Sienna, upstream. Bank 1 Sensor 1 needs an upstream oxygen sensor.
• Fits 2011-2012 Toyota Sienna, upstream. Front oxygen sensor compatible with various vehicle models.

Detailed Description

The Walker 350-64044 oxygen sensor is intended for vehicles that rely on accurate upstream exhaust feedback to manage air-fuel ratio and emissions performance. In Subaru Legacy and Subaru Outback applications, as well as Toyota Sienna coverage, this sensor supports ECU monitoring for the affected bank and sensor location. If the original sensor is failing, the vehicle may store fault codes, run poorly, increase fuel consumption, or trigger the malfunction indicator light.

This part cross-references common OE-style replacement needs for the same application. For Subaru Legacy and Subaru Outback owners searching for an upstream oxygen sensor, or Toyota Sienna drivers needing a Bank 1 Sensor 1 replacement, the 350-64044 provides a direct-fit service part with the specified connector and threaded mount.

Common Issues This Sensor May Address

• Check engine light related to upstream oxygen sensor performance
• Poor engine operation caused by incorrect exhaust feedback
• Higher fuel consumption from inaccurate air-fuel control
• Elevated exhaust emissions from a degraded sensor signal
• Stored ECU fault codes tied to Bank 1 Sensor 1 or front sensor faults

Installation Notes and Tips

Confirm the vehicle’s sensor location before ordering, since this part is listed for upstream and upstream left positions depending on application. Inspect the sensor wiring harness and connector for heat damage, abrasion, or corrosion before installation. Because the sensor is application-specific, verify thread diameter, connector shape, and wire count against the original part on the vehicle.

For Subaru Legacy, Subaru Outback, and Toyota Sienna fitment, match the upstream location exactly to the vehicle’s service information and ECU fault code diagnosis. If the original sensor failed due to wiring or connector damage, address those issues during replacement to help restore normal sensor operation.

Quality Assurance

Walker Products has supplied engine management and oxygen sensor components since 1946 and operates as an Automotive ISO9001/TS 16949 certified company. The 350-64044 is manufactured as an OE replacement part for the specified application and fitment position.