Denso 234-4139 Oxygen Sensor - Downstream or Downstream Front

Denso OE Style Oxygen Sensor 234-4139

This Denso OE Style oxygen sensor is built for direct replacement on select Toyota and Lexus applications. It uses a heated, 4-wire, threaded design with a specific-fit connector for accurate installation and dependable exhaust feedback.

For drivers searching for a Toyota Celica downstream oxygen sensor or a Lexus SC300 downstream front oxygen sensor, Denso 234-4139 provides an OE-style replacement that matches the original fit and electrical layout.

Key Features

• Heated oxygen sensor for faster operating temperature and stable signal output
• Specific-fit design for direct replacement on listed applications
• 4-wire configuration with male connector
• Threaded mounting type with 0.708 in. thread diameter
• 25.59 in. wiring harness length for proper routing
• OE Style construction for factory-like fit and function

OE Style Design

Denso’s OE Style line is built to match original equipment dimensions and connection points for a first-time fit. The sensor uses precision-built components and an aluminum oxide trap layer that helps protect the ceramic element from silicone and lead contamination, supporting consistent engine management performance and long service life. This part number, 234-4139, is a direct replacement choice for owners maintaining emissions system performance on Toyota Celica and Lexus SC300 models.

This part cross-references Bosch (e.g., 13634, 13921) for the same application.

Vehicle Fitment

• Fits 2000-2005 Toyota Celica, Downstream, OE Style
• Fits 1998-2000 Lexus SC300, Downstream Front, OE Style

Common Uses

• Restoring oxygen sensor signal accuracy after sensor aging or contamination
• Addressing check engine light concerns related to downstream sensor performance
• Correcting poor fuel control caused by slow or inconsistent exhaust readings
• Replacing a damaged threaded sensor or worn electrical connector
• Maintaining emissions system operation on Toyota Celica and Lexus SC300 applications

Installation Notes

Verify the sensor position before ordering, since this application covers downstream and downstream front locations. Confirm connector style, wire count, and thread size against the original sensor before installation. Use proper exhaust sensor removal procedures on a cool exhaust system and route the harness away from heat and moving components.

Quality Assurance

Denso manufactures and tests this oxygen sensor to OE standards for fit, function, and durability. The OE-style design is intended to deliver the correct part and the correct fit for the listed Toyota and Lexus applications.