Walker 350-34648 Oxygen Sensor - Downstream

Walker 350-34648 Oxygen Sensor Overview

Walker Products 350-34648 is a heated downstream oxygen sensor built as a direct-fit OE-style replacement for select BMW applications. It is engineered for specific vehicle fitment and ECU feedback, helping maintain accurate exhaust monitoring on BMW 325i, 325Ci, 330i, 330Ci, 525i, 530i, and X3 models.

Walker Products Aftermarket focuses on engine management and oxygen/air-fuel sensors for precise application matching. The 350-34648 follows that approach with a threaded, specific-fit design and a 4-wire heated configuration for downstream use.

Key Features

• Part number: 350-34648
• Heated oxygen sensor for downstream placement
• Specific fit for select BMW models
• 4-wire design with female radiused polygon connector
• Threaded mounting type with 18.0 mm thread diameter
• Wiring harness length: 36.93
• Overall length: 40.47
• Wire gauge measurement: 20

Detailed Description

This Walker oxygen sensor is designed for downstream exhaust monitoring on 2003-2006 BMW 325Ci, 325i, 330Ci, 330i, 525i, 530i, and X3 applications. It provides the ECU with the feedback needed to monitor catalyst efficiency and related emissions-system performance. If the original sensor has aged or failed, the vehicle may store fault codes, run poorly, increase fuel consumption, or illuminate the malfunction indicator light.

Walker Products 350-34648 is built for specific application fitment, so the connector, harness length, and threaded mounting style align with the intended BMW exhaust location. This part number is a practical OE replacement choice for drivers servicing a downstream oxygen sensor on BMW 3 Series, 5 Series, and X3 models.

What It Helps Address

• Check engine light related to downstream oxygen sensor faults
• Poor engine performance caused by inaccurate exhaust feedback
• Higher fuel consumption from a failing sensor signal
• Increased exhaust emissions from degraded sensor operation
• Stored ECU fault codes tied to emissions monitoring

Installation Notes and Tips

Verify the connector shape, wire count, thread diameter, and downstream location before installation. Inspect the sensor wiring harness and connector for heat damage, abrasion, or corrosion, since physical damage can shorten service life. Confirm the vehicle build date and cylinder-bank application where noted in the fitment data for 2003 BMW models.

• Fits 2003-2006 BMW 325Ci, downstream
• Fits 2003-2005 BMW 325i, downstream
• Fits 2003-2006 BMW 330Ci, downstream
• Fits 2004-2005 BMW 330i, downstream
• Fits 2004-2005 BMW 525i, downstream
• Fits 2004-2005 BMW 530i, downstream
• Fits 2004-2006 BMW X3, downstream

Quality Assurance

Walker Products has manufactured engine management and oxygen sensor components since 1946 and operates as an Automotive ISO9001/TS 16949 certified company. The 350-34648 is part of the Walker Products Aftermarket line, developed as a specific-fit replacement for the intended BMW downstream application.