NTK 25721 Oxygen Sensor - Downstream Rear

Direct Fit Oxygen Sensor for Toyota and Lexus

The NTK 25721 direct fit oxygen sensor is a heated, threaded replacement built for specific applications in the downstream rear position. It is engineered for 2004-2016 Toyota Highlander and select Lexus RX models, including RX330, RX350, RX400h, and RX450h, with OE-style fit, form, and function.

NTK’s Direct Fit Oxygen Sensor line focuses on application-specific replacement parts that match original equipment requirements for import and domestic vehicles. The 25721 follows that approach with a 4-wire heated design and a specific-fit configuration for straightforward replacement on the listed Toyota Highlander and Lexus RX applications.

Key Features

• Direct fit oxygen sensor for downstream rear placement
• Heated sensor design for faster operating response
• Specific-fit replacement for listed Toyota and Lexus applications
• 4-wire configuration with 25.5-inch wiring harness length
• 18 mm threaded mounting type
• Built to meet or exceed OE specifications through manufacturing testing

Detailed Description

NTK part number 25721 is an oxygen sensor for the downstream rear location on select Toyota Highlander and Lexus RX vehicles. It is a direct fit replacement that uses the original equipment equivalent design, helping maintain proper exhaust monitoring on 2004-2016 Toyota Highlander, 2004-2006 Lexus RX330, 2006-2008 Lexus RX400h, 2007-2015 Lexus RX350, and 2010-2015 Lexus RX450h applications. This part cross-references DENSO Auto Parts 234-4502 for the same application.

As part of NTK’s Direct Fit Oxygen Sensor line, this sensor is produced with OE application focus and extensive manufacturing validation. NTK is known for ceramic-based sensor technology and broad original equipment coverage, which supports consistent fitment and dependable signal performance in emissions control systems. If you are replacing a downstream rear oxygen sensor on a Toyota Highlander or Lexus RX, NTK 25721 provides a direct replacement path without changing the vehicle’s original sensor layout.

Common Issues This Sensor May Address

• Check engine light related to oxygen sensor performance
• Fault codes tied to downstream rear sensor readings
• Emissions test failure caused by a worn sensor
• Slow or inaccurate exhaust oxygen monitoring
• Sensor replacement needs on aging Toyota Highlander and Lexus RX models

Installation Notes and Tips

Confirm the vehicle’s year, model, and downstream rear sensor position before ordering. This NTK 25721 oxygen sensor uses a threaded mounting type and a 4-wire heated design, so the connector and harness routing should match the original equipment layout on the listed applications. Verify the harness length and sensor location against the removed part before installation.

Quality Assurance

NTK manufactures oxygen sensors with OE-level application focus and tests them during production to support quality and reliability that meet or exceed original equipment specifications. The brand’s background as a major original equipment sensor supplier supports the fit and function expected for emissions control service on Toyota and Lexus applications.