Walker 350-34656 Oxygen Sensor - Downstream

OE Replacement Oxygen Sensor for Audi

Walker OE Replacement oxygen sensor 350-34656 is a specific-fit, heated narrow-band sensor engineered for downstream monitoring on select Audi applications. It is built to deliver the ECU feedback needed for proper fuel control and emissions management on vehicles such as the Audi A4, A5, Q5, and Q7.

The Walker OE Replacement line focuses on application-specific sensor fitment and OE-style function. For shoppers searching for a downstream oxygen sensor for 2019-2020 Audi A4 B1S2 or a replacement oxygen sensor for 2018-2019 Audi Q5 downstream, this part number provides the correct threaded, direct-fit configuration.

Key Features

• Walker OE Replacement part number 350-34656
• Heated narrow-band oxygen sensor for downstream placement
• Specific-fit design for the listed Audi applications
• 4-wire sensor with rectangular male connector
• M18 x 1.5 threaded mounting for direct installation
• 525 mm wiring harness length and 550 mm overall length
• 22 mm wrench size for service access

Detailed Description

This Walker oxygen sensor is engineered as an OE replacement for downstream use on select Audi models, including the Audi A4, Audi A5, Audi A4 allroad, Audi A4 Quattro, Audi A5 Quattro, Audi A5 Sportback, Audi Q5, and Audi Q7. The heated narrow-band design helps the engine management system monitor exhaust oxygen content and maintain accurate ECU feedback after the catalytic converter.

Walker Products develops engine management sensors for application-specific fitment, and 350-34656 follows that approach with the correct connector style, terminal count, wire gauge, and threaded mounting format. If you need a Walker 350-34656 oxygen sensor for a downstream Audi A5 Quattro or downstream Audi Q7, this part is built around the listed vehicle positions and electrical requirements.

What It Helps Address

• Check engine light related to downstream oxygen sensor performance
• Poor fuel control caused by inaccurate exhaust oxygen readings
• Increased fuel consumption from a failing sensor signal
• Elevated exhaust emissions from incorrect ECU feedback
• Fault codes stored in the ECU for the affected sensor circuit

Installation Notes and Tips

Verify the vehicle year, model, and downstream position before ordering. Confirm connector shape, wire count, thread size, and harness length against the original sensor. Inspect the sensor wiring harness and connector for physical damage during diagnosis, since damaged wiring can shorten sensor life and affect system performance.

For fitment reference, this part is listed for Fits 2021-2023 Audi A4, Downstream, Fits 2021-2022 Audi A5, Downstream, Fits 2019 Audi A5, Downstream, Fits 2019-2020 Audi A4, Downstream, Fits 2019-2020 Audi A4 allroad, Downstream, Fits 2019-2020 Audi A4 Quattro, Downstream, Fits 2019-2020 Audi A5 Quattro, Downstream, Fits 2019-2020 Audi A5 Sportback, Downstream, Fits 2019-2020 Audi Q7, Downstream, and Fits 2018-2019 Audi Q5, Downstream.

Quality Assurance

Walker Products has supplied engine management and oxygen/air-fuel sensors since 1946 and manufactures this OE Replacement line for application-specific fitment and diagnostic feedback requirements. The company is ISO 9001/TS 16949 certified, supporting consistent manufacturing and catalog accuracy for service replacement parts.