NTK 25501 Oxygen Sensor - Upstream

Direct Fit Oxygen Sensor Overview

NTK 25501 is a specific-fit oxygen sensor built for direct replacement applications. It uses a threaded mounting design with a 19-inch harness and a non-heated, single-wire configuration for the listed Volkswagen applications.

Compatible With Volkswagen Transporter and Volkswagen Vanagon applications, this NTK oxygen sensor is part of the Direct Fit Oxygen Sensor line and is engineered for OE-style fit, form, and function.

Key Features

• Specific-fit oxygen sensor for direct replacement use
• Non-heated sensor design with one wire
• Threaded mounting type for secure installation
• 19-inch wiring harness length
• 18 mm thread diameter
• NTK 25501 part number for catalog matching

Detailed Description

NTK 25501 is an upstream oxygen sensor application for Volkswagen Transporter and Volkswagen Vanagon models listed in the fitment data. The sensor is designed as an OE-equivalent replacement with a threaded body, non-heated construction, and a 19-inch lead length to match the specified vehicle applications. NTK 25501 is backed by NTK's role as a major original equipment oxygen sensor manufacturer and by manufacturing controls focused on fit and reliability.

The Direct Fit Oxygen Sensor product line is intended to streamline replacement selection by offering application-specific sensors rather than universal parts. For buyers searching for a Volkswagen Transporter oxygen sensor or Volkswagen Vanagon upstream oxygen sensor, NTK 25501 provides a cataloged match for the listed years and emissions configuration.

What It Is Used For

• Replacing a worn or failed upstream oxygen sensor
• Addressing oxygen sensor fault codes
• Restoring air-fuel mixture feedback to the engine control system
• Correcting drivability issues related to inaccurate exhaust oxygen readings
• Supporting emissions system operation on the listed Volkswagen applications

Installation Notes and Tips

Install only on the specific Volkswagen Transporter and Volkswagen Vanagon applications shown in the fitment table. Confirm the upstream location, threaded mounting style, 18 mm thread diameter, and non-heated single-wire configuration before installation. Use the part number 25501 to verify catalog match before ordering or service work.

Quality Assurance

NTK states that its oxygen sensors are extensively tested during manufacturing to meet or exceed OE specifications. The brand is part of the NGK family of products and is recognized as a major original equipment oxygen sensor supplier. Part number 25501 is built to support OE-style fit and function for the listed applications.