Walker 350-34078 Oxygen Sensor - Downstream, Upstream, Upstream Front or Upstream Rear

Walker 350-34078 Oxygen Sensor Overview

Walker Products 350-34078 is a heated oxygen sensor built as a specific-fit OE replacement for select Ford, Lincoln, and Mercury applications. It is engineered for the correct mounting position and ECU feedback on vehicles that use a threaded, 4-wire sensor design.

For shoppers searching for a Ford Escape upstream oxygen sensor, Ford Fusion upstream or downstream oxygen sensor, Lincoln MKZ upstream oxygen sensor, or Mercury Milan upstream oxygen sensor, this part number provides the application-specific fit needed for proper exhaust monitoring.

Key Features

• Heated oxygen sensor for faster operating response
• Specific-fit design for the listed vehicle applications
• 4-wire configuration with female connector
• Radiused polygon connector shape for application-specific fitment
• Threaded mounting type with 18.0 mm thread diameter
• 13.31 in. wiring harness length and 16.85 in. overall length
• Walker Products Aftermarket line engineered for engine management and oxygen/air-fuel sensor replacement

Fitment and Application Details

Fits 2011-2012 Ford Escape, upstream. Fits 2011-2012 Ford Fusion, upstream rear, upstream front, and downstream depending on the listed position. Fits 2011-2012 Lincoln MKZ, upstream rear and upstream front. Fits 2011 Mercury Milan, upstream. Fits 2011 Mercury Milan, upstream.

Walker Products 350-34078 is built for vehicles that require a direct-position oxygen sensor replacement rather than a universal sensor. The Walker Products Aftermarket line focuses on engine management sensors developed for specific applications, helping maintain the diagnostic feedback the ECU expects from the exhaust system. This makes it a practical choice when replacing a failed upstream or downstream oxygen sensor on Ford Escape, Ford Fusion, Lincoln MKZ, or Mercury Milan models.

What It Helps Address

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

Installation Notes and Tips

Confirm the exact position before ordering, since this part number is listed for upstream, upstream front, upstream rear, and downstream locations across different applications. Inspect the sensor wiring harness and connector for heat damage, abrasion, or corrosion before installation. Verify the 18.0 mm threaded mounting point and connector style match the original sensor on the vehicle.

For best results, compare the removed sensor to Walker Products 350-34078 before installation and clear any stored fault codes after the repair is completed.

Quality Assurance

Walker Products states that its engine management and oxygen/air-fuel sensors are developed as OE replacement parts for worldwide vehicle applications. The company is ISO 9001/TS 16949 certified and has supplied engine management and fuel system components since 1946.