NTK 25181 Oxygen Sensor - Downstream Left

Direct Fit Oxygen Sensor for Hyundai and Kia

NTK 25181 is a direct fit heated oxygen sensor for downstream left applications on select Hyundai and Kia vehicles. It is built for specific-fit replacement in B2S2 locations, with the correct threaded mounting and 4-wire configuration for a clean OE-style installation.

As part of NTK’s Direct Fit Oxygen Sensor line, this sensor focuses on application-specific coverage, precise fit, and OE-level signal performance for import and domestic vehicles. NTK’s background as a major original equipment oxygen sensor supplier supports the engineering behind this replacement part.

Key Features

• Heated oxygen sensor for faster operating response
• Specific fit design for direct replacement use
• 18 mm thread diameter with threaded mounting
• 4-wire configuration with 18-inch wiring harness length
• Built for downstream left B2S2 locations on listed applications
• NTK part number 25181 for easy catalog lookup

Detailed Product Information

NTK 25181 is engineered for select 2002-2010 Hyundai and Kia models, including the Hyundai Sonata, Santa Fe, Tiburon, and Tucson, as well as the Kia Optima, Magentis, and Sportage. This direct fit oxygen sensor is intended for downstream left placement and matches the specified OE-style application requirements for those vehicles. If you are replacing a worn sensor on a Hyundai Sonata or Kia Optima, NTK 25181 provides the correct fitment profile for the listed B2S2 positions.

NTK’s Direct Fit Oxygen Sensor line is developed with controlled ceramic manufacturing and extensive production testing to support consistent fit, form, and function. This part cross-references DENSO Auto Parts 234-4193 for the same application.

Common Problems This Sensor Can Address

• Check engine light related to oxygen sensor performance
• Incorrect air-fuel ratio feedback from a failing downstream sensor
• Emissions test failure caused by degraded sensor response
• Rough or inconsistent engine management data from an aging sensor
• Replacement needs after sensor contamination or internal wear

Installation Notes and Tips

Verify the vehicle’s year, make, model, and downstream left B2S2 location before ordering. Confirm the 4-wire connector style, 18 mm thread diameter, and threaded mounting point match the original sensor. For best results, inspect the harness routing and connector condition during replacement on Hyundai Tucson, Hyundai Santa Fe, and Kia Sportage applications.

Quality Assurance

NTK manufactures oxygen sensors with OE-focused application coverage and production testing to help ensure reliable operation that meets or exceeds original equipment specifications. The NTK 25181 is part of the brand’s direct fit sensor program for accurate replacement on the listed Hyundai and Kia vehicles.