Bosch 18039 Oxygen Sensor - Downstream or Downstream Left

Reliable Oxygen Sensor for Lexus and Toyota Vehicles

The Bosch Validated Oxygen Sensor 18039 is designed specifically for select Lexus and Toyota models, including the Prius, Highlander, and RX series. This narrow-band heated oxygen sensor ensures accurate emissions control and optimal engine performance.

• Specific fit for Lexus CT200h, RX350, RX450h and Toyota Prius, Prius C, Prius Plug-In, Prius V, Highlander
• Heated narrow-band oxygen sensor with 4-wire design for precise readings
• Threaded mounting type with 18 mm thread diameter and 22 mm hex size
• Durable metal housing with steel finish and male blade terminals
• Includes 19.9-inch wiring harness with square male connector

About the Bosch Validated Oxygen Sensor Line

The Bosch Validated Oxygen Sensor product line focuses on delivering sensors that meet strict OEM specifications for fit, form, and function. The 18039 sensor is engineered to provide reliable emissions feedback and maintain engine efficiency in specific Lexus and Toyota hybrid and gasoline models. This line emphasizes compatibility and quality to support emission control systems effectively.

Product Details and Specifications

This Bosch oxygen sensor features a narrow-band heated design with four wires and blade terminals, ensuring accurate oxygen level detection in the exhaust stream. The sensor’s threaded mounting type with an 18 mm diameter and 22 mm hex size allows for secure installation. The metal housing finished in steel provides durability under high-temperature conditions. The wiring harness length is 19.9 inches, with an overall length of 23.6 inches, including a 22.4-inch length from the sealing surface to the connector end. The connector is a square-shaped male type with four terminals, matching the specific fitment requirements of the listed Lexus and Toyota models.

Common Applications and Issues Addressed

• Restores proper air-fuel ratio monitoring for Lexus RX350 and RX450h
• Resolves check engine light triggers related to oxygen sensor faults in Toyota Prius models
• Improves fuel efficiency and reduces emissions in Highlander and CT200h vehicles
• Prevents rough idling and engine performance issues caused by faulty sensors
• Supports hybrid system emissions compliance in Prius Plug-In and Prius V

Installation Notes and Tips

Ensure the engine is cool before removing the old oxygen sensor to avoid burns. Use a 22 mm oxygen sensor socket for removal and installation. Verify the connector type and wiring harness length match your vehicle’s specifications. The threaded mounting requires proper torque to avoid leaks or damage. No mounting bracket is included, so use the existing mounting point on the exhaust system. Confirm compatibility with your Lexus or Toyota model before installation.

Quality Assurance and Warranty

The Bosch Validated Oxygen Sensor 18039 is manufactured to meet OEM standards for durability and performance. It includes a heated element to ensure quick sensor response and reliable operation under various driving conditions. While specific warranty details may vary, Bosch products typically come with a limited warranty covering defects in materials and workmanship to provide confidence in your purchase.