NTK 25604 Oxygen Sensor - Downstream, Downstream Left or Downstream Right

Direct Fit Oxygen Sensor for OE-Style Replacement

The NTK Direct Fit Oxygen Sensor 25604 is a heated, specific-fit replacement built for downstream applications that require OE-style sensor response and connector fitment. It is designed for select Audi and Volkswagen models, including Volkswagen Beetle, Jetta, Golf, and Touareg applications, as well as Audi A4, A4 Quattro, TT, TT Quattro, and related fitments.

NTK 25604 uses a threaded mounting design with a 4-wire configuration and a 27.5-inch wiring harness length for direct replacement service. For drivers searching for a downstream oxygen sensor for Volkswagen Beetle or an OE-spec oxygen sensor for Audi A4 Quattro, this part is built to match the original application layout.

Key Features

• Direct Fit Oxygen Sensor from NTK
• Heated sensor design for downstream emissions control applications
• Specific fit for confirmed Audi and Volkswagen applications
• 4-wire construction with threaded mounting
• 27.5-inch wiring harness length
• 18 mm thread diameter
• OE-style fit, form, and function for replacement service

Product Details

NTK is part of the NGK family of products and focuses on oxygen sensor coverage for import and domestic vehicles. The 25604 part number is engineered with original-equipment-style dimensions and application-specific calibration support, helping maintain proper exhaust feedback on downstream sensor locations. This makes it a practical choice for Volkswagen Jetta downstream oxygen sensor replacement, Audi TT Quattro downstream right sensor service, and other listed applications where exact connector and thread fitment matter.

This part cross-references Bosch 16034 and DENSO Auto Parts 234-4753 for the same application.

What It Helps Address

• Check engine light related to oxygen sensor performance
• Fault codes tied to downstream sensor response
• Incorrect air-fuel feedback from a worn sensor
• Emissions inspection failures caused by sensor degradation
• Connector or harness mismatch during replacement

Installation Notes and Tips

Confirm the vehicle’s sensor position before ordering, since this part is listed for downstream, downstream right, and downstream left locations depending on application. Verify thread diameter, wire count, and harness length against the original sensor before installation. For best results, inspect the exhaust bung and wiring routing, and compare the connector style to the removed unit before final fitment.

Quality Assurance

NTK manufactures oxygen sensors with extensive testing during production to support quality and reliability that meets or exceeds OE specifications. As a major original equipment oxygen sensor supplier, NTK 25604 is built for dependable replacement performance in confirmed Audi and Volkswagen applications.

Compatible Vehicles

• Fits 1998-2010 Volkswagen Beetle, Downstream
• Fits 2006-2010 Volkswagen Beetle, Downstream
• Fits 2007-2010 Volkswagen Golf City, Downstream
• Fits 2007-2009 Volkswagen Jetta City, Downstream
• Fits 2005-2006 Audi A4 Quattro, Downstream Right
• Fits 2005-2006 Audi A4 Quattro, Downstream Left
• Fits 2004-2006 Audi TT Quattro, Downstream Right
• Fits 1999-2006 Volkswagen Golf, Downstream
• Fits 2004-2006 Volkswagen Touareg, Downstream Right
• Fits 2005 Audi A4, Downstream Right
• Fits 2005 Audi A4, Downstream Left
• Fits 2005 Volkswagen Beetle, Downstream
• Fits 1999-2005 Volkswagen Jetta, Downstream
• Fits 2004-2005 Volkswagen Jetta, Downstream
• Fits 2003 Volkswagen Jetta, Downstream
• Fits 2000-2001 Audi TT, Downstream