Walker 350-34957 Oxygen Sensor - Downstream

OE Replacement Oxygen Sensor for Audi and Volkswagen

Walker OE Replacement oxygen sensor part number 350-34957 is a specific-fit, heated narrow-band sensor built for downstream applications. It is engineered to provide the ECU with the feedback needed for proper fuel control and emissions monitoring on select Audi Q3, Audi A3, Audi A1, Volkswagen Tiguan, Volkswagen Taos, Volkswagen Nivus, and Volkswagen Golf models.

Key Features

• Heated narrow-band oxygen sensor for downstream placement
• Specific-fit design for the listed Audi and Volkswagen applications
• 4-wire configuration with blade terminals
• Female connector with D-shaped connector housing
• M18 x 1.5 thread size and screw-in mounting type
• Standard replacement grade for OE-style service
• Overall length: 850.00; wiring harness length: 825.00

Product Details

Walker Products OE Replacement sensors are developed as direct-fit service parts for vehicle-specific applications. Part number 350-34957 is designed for downstream use on the exhaust system, where it helps the engine control unit monitor exhaust oxygen content and adjust system operation accordingly. This Walker oxygen sensor is a practical choice for drivers searching for a downstream oxygen sensor for 2018-2024 Volkswagen Tiguan, a replacement oxygen sensor for 2016-2020 Audi A3, or a downstream sensor for 2024-2025 Audi Q3.

The Walker OE Replacement line focuses on application-specific fitment and diagnostic feedback requirements. For shoppers comparing Walker 350-34957 against other service parts, this sensor is built around the listed connector style, terminal count, thread size, and heated narrow-band design to match the original installation point.

What It Can Help Address

• Check engine light related to downstream oxygen sensor faults
• Poor fuel economy caused by inaccurate exhaust feedback
• Elevated exhaust emissions from a failing sensor
• Rough engine operation tied to incorrect ECU sensor input
• Physical damage to the sensor, wiring harness, or connector

Installation Notes and Tips

Confirm the downstream position, connector shape, terminal count, and thread size before installation. Inspect the sensor wiring harness and connector for heat damage, corrosion, or abrasion, since those issues can shorten service life and affect signal quality. For fitment-based searches, this part is listed for 2024-2025 Audi Q3, downstream; 2019-2021 Audi Q3, downstream; 2023-2024 Volkswagen Nivus, downstream; 2024 Volkswagen Taos, downstream; 2021-2022 Volkswagen Taos, downstream; 2018-2024 Volkswagen Tiguan, downstream; 2022-2023 Audi Q3, downstream, B1S2; 2016-2020 Audi A3, downstream; 2017-2018 Audi A1, downstream; and 2015-2018 Volkswagen Golf, downstream.

Quality Assurance

Walker Products builds engine management and oxygen/air-fuel sensors as OE replacement parts for specific vehicle applications. The company states that its sensor programs are developed around application fitment and ECU feedback requirements, with manufacturing supported by ISO 9001/TS 16949 quality systems.