NTK 25768 Oxygen Sensor - Downstream

Direct Fit Oxygen Sensor Overview

The NTK 25768 is a direct fit heated oxygen sensor built for specific downstream applications. It is engineered for BMW models that require an OE-equivalent replacement with threaded mounting and a 4-wire configuration.

As part of NTK's Direct Fit Oxygen Sensor line, this sensor focuses on original equipment-style fit, form, and function. The 25768 is a practical choice for BMW 340i, 440i, 540i, X3, and related applications where accurate exhaust feedback is required.

Key Features

• Direct fit design for specific downstream applications
• Heated oxygen sensor for faster operating response
• 4-wire configuration with threaded mounting
• 21.7500 wiring harness length
• 18.000 thread diameter
• OE-equivalent design for proper replacement fitment

Detailed Description

NTK 25768 is a specific-fit oxygen sensor intended for downstream placement on select BMW vehicles, including the 340i, 440i, 540i, X3, X4, 740i, M240i, and 640i xDrive Gran Turismo applications listed in the fitment data. The sensor uses a heated design and threaded mounting to match the original installation style, helping maintain the correct exhaust monitoring setup. This part number, 25768, is also cross-referenced to 11788611294 for the same application.

NTK positions this sensor within its Direct Fit Oxygen Sensor line, which is built around OE-style coverage and application-specific replacement parts. For buyers searching for a BMW downstream oxygen sensor, NTK 25768 offers a direct replacement path without universal-fit compromises.

What This Part Helps Address

• Faulty downstream oxygen sensor readings
• Check engine light concerns related to exhaust monitoring
• Incorrect air-fuel feedback from a worn sensor
• Replacement needs after sensor aging or contamination
• Restoring proper emissions system operation

Installation Notes and Tips

Verify the downstream position, wire count, thread diameter, and harness length before installation. Confirm the vehicle application against the fitment list for your BMW 340i, 440i, X3, or other listed model before ordering. Use the existing threaded mounting location and follow the vehicle service procedure for sensor replacement.

Quality Assurance

NTK states that its oxygen sensors are extensively tested during manufacturing to meet or exceed OE specifications. The brand also notes its role as a major original equipment oxygen sensor supplier, with product development focused on fit, form, and function.