Walker 350-34121 Oxygen Sensor - Downstream Front

Walker 350-34121 Oxygen Sensor for Nissan Altima

Walker Products 350-34121 is a heated oxygen sensor built as a specific-fit replacement for select Nissan Altima applications. It is engineered to provide the ECU with the feedback needed for proper fuel control and emissions monitoring.

Key Features

• Heated oxygen sensor for faster operating response
• Specific fitment for the listed Nissan Altima applications
• Threaded mounting type with 18.0 mm thread diameter
• 4-wire design with 20-gauge wiring
• Radiused polygon male connector for application-specific connection
• Wiring harness length: 11.73 in.; overall length: 15.28 in.

Product Details

Walker Products Aftermarket focuses on engine management and oxygen/air-fuel sensors built to OE-style application requirements. Part number 350-34121 is made for the downstream front position on select 2002-2004 Nissan Altima models, including 2004 Altima vehicles built up to January 2004. This sensor helps the engine control unit monitor exhaust oxygen content so the system can maintain correct air-fuel strategy and emissions performance.

Walker 350-34121 is a direct-fit oxygen sensor for Nissan Altima owners replacing a worn or faulted downstream front sensor. The design matches the specified mounting, connector, and wiring configuration for the listed applications, which helps simplify replacement and restore proper sensor feedback to the ECU.

What It Helps Address

• Check engine light related to oxygen sensor performance
• Poor fuel economy caused by inaccurate exhaust feedback
• Rough engine operation tied to incorrect air-fuel control
• Elevated exhaust emissions from a failing heated oxygen sensor
• Stored ECU fault codes for the downstream front sensor circuit

Installation Notes and Tips

Verify the vehicle is a 2002-2004 Nissan Altima with the downstream front sensor location before ordering. For 2004 models, confirm the build date is up to January 2004 where noted. Inspect the sensor wiring harness and connector for heat damage, corrosion, or physical wear before installation, since damaged wiring can shorten sensor life and affect operation. Confirm the threaded mounting point and connector style match the original part before replacement.

Quality Assurance

Walker Products has manufactured engine management components since 1946 and operates as an ISO 9001/TS 16949 certified company. Part number 350-34121 is built for the specified application and fitment position to deliver the diagnostic feedback required by the ECU.