Walker 350-34106 Oxygen Sensor - Downstream

Walker 350-34106 Downstream Oxygen Sensor

Walker 350-34106 is a specific-fit heated oxygen sensor engineered as an OE-style replacement for downstream monitoring on select Nissan Quest and Mercury Villager applications. It is built to deliver the diagnostic feedback the ECU expects, helping maintain proper fuel control and emissions system operation.

Key Features

• Heated oxygen sensor for downstream placement
• Specific-fit design for direct application matching
• 4-wire configuration with female connector
• Radiused polygon connector shape for vehicle-specific fitment
• Threaded mounting with 18.0 mm thread diameter
• Wiring harness length: 22.76 in.; overall length: 26.3 in.
• Wire gauge: 20

Product Details

Walker Products Aftermarket focuses on engine management and oxygen/air-fuel sensors built for OE replacement use across many vehicle platforms. Part number 350-34106 is designed for downstream sensor locations and is listed for 1999 Mercury Villager, downstream; 2000-2002 Mercury Villager, downstream; 1999-2000 Nissan Quest, downstream; and 2001-2002 Nissan Quest, downstream. This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

For Nissan Quest and Mercury Villager vehicles, this downstream oxygen sensor supports the ECU’s ability to monitor exhaust stream performance after the catalytic converter. Walker 350-34106 is built for the specified fitment position and connector style, making it a practical replacement when the original sensor has aged, triggered a fault code, or no longer provides stable feedback.

Common Issues This Sensor Can Address

• Check engine light related to downstream oxygen sensor performance
• Poor fuel economy caused by inaccurate exhaust feedback
• Elevated exhaust emissions from a worn sensor
• Stored ECU fault codes tied to the affected sensor circuit
• Rough engine operation linked to sensor signal degradation

Installation Notes and Tips

Confirm downstream location before installation and compare the connector, thread diameter, and harness length to the original part. Inspect the sensor wiring harness and connector for heat damage, corrosion, or abrasion, since physical damage can shorten service life and affect signal quality. Verify the vehicle application against the listed fitment for 1999-2002 Mercury Villager and 1999-2002 Nissan Quest models.

Quality Assurance

Walker Products has manufactured engine management components since 1946 and operates as an ISO 9001/TS 16949 certified company. The 350-34106 is produced as a vehicle-specific replacement sensor for the listed applications and fitment position.