Denso 234-4168 Oxygen Sensor - Downstream, Downstream Front or Downstream Left

Denso OE Style Oxygen Sensor 234-4168

Denso 234-4168 is a specific-fit heated oxygen sensor built to OE-style dimensions for direct replacement on select Toyota, Lexus, and Scion applications. It is engineered for accurate exhaust feedback, stable drivability, and a first-time fit on downstream locations.

The OE Style line focuses on exact replacement geometry and connector match, making it a practical choice for drivers servicing a 2004-2007 Toyota Highlander downstream left, a 2004-2006 Lexus RX330 downstream left, or a 2004-2006 Toyota Sienna downstream front. This part number, 234-4168, is also used across additional downstream applications including Scion iQ, Scion xB, and Toyota Venza coverage.

• Heated oxygen sensor for faster operating response
• Specific fit design for direct replacement
• 4-wire configuration with male connector
• Threaded mounting type with 0.708 in. thread diameter
• 13.78 in. wiring harness length for OE-style routing
• Built to strict OE standards for replacement accuracy
• Aluminum oxide trap layer helps protect the ceramic element from silicone and lead contamination

Denso manufactures this oxygen sensor to match original equipment expectations for fit, function, and connector layout. The sensor is designed to support proper air-fuel feedback after installation, which is important for emissions control and consistent engine operation. If you are replacing a downstream oxygen sensor on a Toyota Highlander, Lexus RX330, or Toyota Sienna, Denso 234-4168 provides an OE-style solution with the correct threaded mount and harness length.

This part cross-references Bosch (e.g., 15569, 18018) for the same application.

What This Oxygen Sensor Helps Address

• Check engine light related to downstream oxygen sensor faults
• Erratic fuel trim readings caused by a worn sensor
• Reduced fuel economy from inaccurate exhaust feedback
• Failed emissions testing tied to sensor performance
• Slow sensor response after extended heat and contamination exposure

Installation Notes and Tips

Confirm the sensor position before ordering, since this application covers downstream, downstream left, and downstream front locations depending on vehicle. Match the connector style, wire count, and thread diameter to the original sensor before installation. Inspect the harness routing and exhaust threads for damage, and verify the sensor seats fully in the threaded bung without cross-threading.

Quality Assurance

Denso builds and tests this OE Style oxygen sensor to strict original-equipment standards for replacement accuracy and consistent performance. The design includes an aluminum oxide trap layer intended to help protect the sensing element from silicone and lead contamination, supporting long service life in demanding exhaust conditions.