Walker 350-33012 Oxygen Sensor - Upstream Rear

Walker Oxygen Sensor for Mazda Millenia

Walker Products Part Number 350-33012 is a heated oxygen sensor built as a specific-fit OE replacement for select Mazda Millenia applications. It is engineered for the upstream rear exhaust position and provides the ECU with the feedback needed for accurate fuel control and emissions monitoring.

Key Features

• Specific-fit oxygen sensor for targeted vehicle application
• Heated sensor design for faster operating temperature
• 3-wire configuration with female connector
• Threaded mounting type with 18.0 mm thread diameter
• Wiring harness length: 11.34 in.
• Overall length: 14.88 in.
• Walker Products Aftermarket line for engine management and oxygen/air-fuel sensor replacement

Product Details

Walker Products 350-33012 is designed for 1995-2002 Mazda Millenia, upstream rear. This oxygen sensor is manufactured for the specified fitment position so it can deliver the diagnostic signal the ECU expects from the rear exhaust system. Walker Products has focused on engine management and sensor replacement parts since 1946, and this part reflects that OE-style application-specific approach. This part cross-references Walker Products Aftermarket 350-33012 for the same application.

What It Helps Address

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

Installation Notes

Verify the connector shape, wire count, thread diameter, and mounting position before installation. Inspect the sensor wiring harness and connector for heat damage, corrosion, or abrasion, since damaged wiring can shorten sensor life and affect signal quality. Confirm the vehicle application as 1995-2002 Mazda Millenia, upstream rear, before ordering or replacing the part.

Quality Assurance

Walker Products manufactures engine management sensors under ISO 9001/TS 16949 quality systems and supplies application-specific replacement parts for vehicle electronics and emissions control.