NTK 25689 Oxygen Sensor - Downstream, Downstream Right or Upstream

Direct Fit Oxygen Sensor

NTK Oxygen Sensor 25689 is a specific-fit, heated oxygen sensor built for direct replacement applications. It uses a threaded mounting design and a 4-wire configuration with a 43.25-inch harness length for broad OE-style coverage.

Key Features

• Heated oxygen sensor for precise exhaust feedback
• Specific-fit design for direct replacement applications
• Threaded mounting type with 18 mm thread diameter
• 4-wire construction with 43.25-inch wiring harness
• NTK direct fit line for OE-style application coverage

Detailed Description

NTK 25689 is part of the Direct Fit Oxygen Sensor line, engineered to match original equipment fit, form, and function. As a heated oxygen sensor, it supports accurate air-fuel monitoring in emissions control systems. This part cross-references DENSO Auto Parts 234-4874 and Spectra Premium OS5030 for the same application. Compatible With Audi TT, Volkswagen Golf, Volkswagen Phaeton, Volkswagen Beetle, and Volkswagen Jetta applications listed in the fitment data, including downstream and upstream positions where specified. NTK 25689 is a practical choice for drivers servicing Audi TT and Volkswagen Golf emissions systems with a direct-fit replacement sensor.

What It Is Used For

• Replacing a failed oxygen sensor that triggers emissions-related fault codes
• Restoring accurate exhaust oxygen feedback to the engine control system
• Addressing poor fuel control caused by an aging heated sensor
• Correcting drivability issues linked to inaccurate air-fuel ratio readings
• Servicing direct-fit emissions control applications on import vehicles

Installation Notes and Tips

Verify the sensor position, connector style, thread diameter, and harness length against the original part before installation. This unit uses a threaded mount and a specific-fit design, so it should be matched to the exact application listed in the fitment data. Confirm the vehicle year, make, model, and sensor location before ordering.

Quality Assurance

NTK is part of the NGK family of products and is a major original equipment oxygen sensor manufacturer. Each sensor is extensively tested during production to help ensure quality and reliability that meet or exceed OE specifications.