Walker 350-34133 Oxygen Sensor - Downstream

OE Replacement Oxygen Sensor for Mazda

Walker OE Replacement oxygen sensor 350-34133 is a specific-fit downstream sensor engineered for direct replacement on select Mazda applications. It uses a heated narrow-band design with a square connector and 4-wire layout to deliver the ECU feedback needed for proper fuel control and emissions monitoring.

Built for Mazda CX-5, Mazda 3, Mazda CX-30, Mazda 6, and Mazda CX-9 downstream positions, this sensor is matched to the application for fitment position, thread size, and connector style. If your vehicle is showing an oxygen sensor fault, poor fuel economy, or an illuminated MIL, 350-34133 is the OE-style replacement to inspect first.

Key Features

• Walker OE Replacement line for application-specific sensor coverage
• Heated narrow-band oxygen sensor for downstream use
• Specific fit with square connector and male spade terminals
• 4-wire configuration with 20-gauge wiring
• M18 x 1.5 threaded mounting with 22 mm wrench size
• Overall length: 773 mm; wiring harness length: 765 mm

Product Details

The Walker Products OE Replacement line focuses on direct-fit engine management components built for the exact vehicle application. Part number 350-34133 is a downstream oxygen sensor designed to provide the ECU with the feedback required for emissions and fuel-trim control on select Mazda models. It is a standard replacement, heated, narrow-band sensor with a threaded mount, making it a practical choice for Mazda CX-5 downstream oxygen sensor replacement, Mazda 3 downstream O2 sensor service, and other listed Mazda fitments.

This part cross-references common OE-style replacement needs for the same application.

What It Helps Address

• Check engine light related to downstream oxygen sensor performance
• Poor fuel economy caused by incorrect exhaust feedback
• Elevated exhaust emissions from inaccurate air-fuel monitoring
• Rough engine operation tied to sensor signal issues
• Fault codes stored in the ECU for the affected sensor circuit

Installation Notes and Tips

Before replacement, inspect the sensor wiring harness and connector for heat damage, corrosion, or broken terminals. Confirm the downstream location and thread size match the original part, and verify the exhaust bung is clean before threading in the new sensor. After installation, clear diagnostic trouble codes and confirm the repair with a scan tool if required.

Quality Assurance

Walker Products manufactures engine management and oxygen/air-fuel sensors as OE replacement parts for global vehicle applications. The company is ISO 9001/TS 16949 certified and has supplied automotive sensor and fuel system components since 1946.

Compatible With

• Fits 2022-2025 Mazda CX-5, Downstream
• Fits 2017 Mazda CX-5, Downstream
• Fits 2019-2022 Mazda 3, Downstream
• Fits 2021-2022 Mazda CX-30, Downstream
• Fits 2018-2021 Mazda 6, Downstream; B1S2
• Fits 2018-2021 Mazda CX-5, Downstream; B1S2
• Fits 2020 Mazda CX-30, Downstream; B1S2
• Fits 2016-2018 Mazda CX-9, Downstream