Walker 350-34509 Oxygen Sensor - Center, Downstream Left or Upstream

Walker 350-34509 Oxygen Sensor Overview

Walker Products 350-34509 is a heated oxygen sensor built as a specific-fit OE replacement for select Volkswagen and Audi applications. It is engineered to deliver the ECU feedback needed for accurate fuel control and emissions monitoring, including upstream and downstream positions where listed.

Walker Products Aftermarket focuses on application-specific engine management sensors, and this oxygen sensor follows that approach with the correct connector style, thread size, wire count, and harness length for the listed vehicles. For shoppers searching for a 2013-2017 Volkswagen Polo upstream oxygen sensor or a 2005-2011 Audi A4/A6 downstream left oxygen sensor, part number 350-34509 is the direct reference to check.

Key Features

• Heated oxygen sensor for faster operating response
• Specific fit design for the listed vehicle applications
• 4-wire configuration with 20-gauge wiring
• Radiused polygon male connector
• Threaded mounting with 18.0 mm thread diameter
• 21.18 in. wiring harness length and 24.72 in. overall length
• Walker Products Aftermarket part number 350-34509

Detailed Description

Walker Products 350-34509 is an emission control sensor intended for precise air-fuel feedback in supported Volkswagen Polo, Volkswagen Bora, Audi A4, Audi A4 Quattro, Audi A6, and Audi A6 Quattro applications. It is listed for upstream, downstream left, and center positions depending on the vehicle, making it a fitment-specific replacement for common oxygen sensor service needs. The heated design helps the sensor reach operating temperature quickly so the ECU can monitor exhaust content and adjust fuel delivery accordingly.

This Walker Products oxygen sensor is built for vehicles that rely on accurate diagnostic feedback from the exhaust stream. If the original sensor is aging or damaged, the engine may run poorly, fuel consumption can increase, emissions can rise, and the malfunction indicator light may illuminate. Part number 350-34509 is a practical OE-style replacement when the sensor, wiring harness, or connector has been compromised.

This part cross-references Bosch 17014 and Denso 234-9005 for the same application.

What It Helps Address

• Check engine light related to oxygen sensor performance
• Rough running caused by incorrect exhaust feedback
• Increased fuel consumption from inaccurate air-fuel correction
• Elevated exhaust emissions from a failing sensor
• Fault codes stored in the ECU for the affected sensor circuit

Installation Notes and Tips

Verify the sensor position before ordering, since this part is listed for upstream, downstream left, and center locations across different vehicles. Confirm connector shape, thread diameter, and harness length against the original sensor before installation. Inspect the wiring harness and connector for heat damage, abrasion, or corrosion, since physical damage can shorten sensor life and affect signal quality.

For fitment searches, this part is commonly referenced as a 2013-2017 Volkswagen Polo upstream oxygen sensor, a 2010 Volkswagen Bora center oxygen sensor, and a 2005-2011 Audi A4/A6 downstream left oxygen sensor. Always match the vehicle application and sensor position to the catalog listing before service.

Quality Assurance

Walker Products Aftermarket manufactures application-specific engine management sensors for OE-style replacement use and operates as an Automotive ISO9001/TS 16949 certified company. Since 1946, Walker Products has supplied oxygen and air-fuel sensors for a wide range of vehicle applications, including Volkswagen and Audi platforms.