Walker 350-34503 Oxygen Sensor - Downstream Left

Walker 350-34503 Oxygen Sensor Overview

Walker Products 350-34503 is a heated oxygen sensor built as a specific-fit OE replacement for select Lexus applications. It is engineered to deliver the diagnostic feedback the ECU expects, helping maintain proper fuel control and emissions monitoring on the downstream left side.

Walker Products Aftermarket focuses on engine management and oxygen/air-fuel sensors for exact application fitment. The 350-34503 follows that approach with a threaded, 4-wire design and a radiused polygon male connector for direct replacement use on covered Lexus models.

Key Features

• Heated oxygen sensor for downstream left placement
• Specific-fit design for direct application matching
• 4-wire configuration with 22-gauge wiring
• 42.05 wiring harness length and 45.59 overall length
• 18.0 thread diameter with threaded mounting type
• Radiused polygon male connector for vehicle-specific connection
• OE replacement design for ECU feedback and emissions monitoring

Detailed Product Description

The Walker 350-34503 oxygen sensor is designed for Lexus vehicles that require a downstream left sensor with OE-style fitment and signal output. As a heated sensor, it helps the engine management system monitor exhaust conditions after the catalytic converter, supporting accurate diagnostic feedback to the ECU. This part number is used on applications including Lexus GS300, Lexus IS300, Lexus IS350, Lexus RC300, and Lexus RC350, with coverage spanning 2006, 2018-2025 depending on model and build date. If you are searching for a Lexus RC300 downstream left oxygen sensor or a Lexus IS350 downstream left oxygen sensor, Walker 350-34503 is the direct-fit option listed for those applications.

Walker Products Aftermarket 350-34503 is built for specific vehicle fitment rather than universal use, which helps ensure the connector, harness length, thread size, and sensor position align with the original equipment layout. This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

Common Issues This Sensor Can Address

• Check engine light or malfunction indicator light related to the downstream oxygen sensor
• Poor fuel economy caused by inaccurate exhaust feedback
• Elevated exhaust emissions from a failing sensor signal
• Rough engine operation tied to incorrect ECU input
• Fault codes stored in the ECU for the affected sensor circuit

Installation Notes and Tips

Confirm the vehicle’s year, model, build date, and downstream left position before ordering. Inspect the sensor wiring harness and connector for heat damage, abrasion, or corrosion, since physical damage can shorten sensor life and affect operation. Verify thread diameter and connector style against the original part before installation on Lexus GS300, Lexus IS300, Lexus IS350, Lexus RC300, or Lexus RC350 applications.

Quality Assurance

Walker Products has manufactured engine management components since 1946 and operates as an Automotive ISO9001/TS 16949 certified company. The 350-34503 is produced as an OE replacement sensor for the specified Lexus applications and fitment position.