NTK 25166 Oxygen Sensor - Downstream Right

Direct Fit Oxygen Sensor for Hyundai and Kia

NTK 25166 is a direct fit heated oxygen sensor built for specific downstream right applications. It is engineered for the Hyundai Santa Fe, Hyundai Sonata, Kia Magentis, and Kia Optima listed below, with OE-style fit, form, and function for the B1S2 location.

As part of NTK’s Direct Fit Oxygen Sensor line, this sensor reflects the brand’s focus on application-specific coverage and OE-level design. NTK manufactures oxygen sensors with ceramic technology and extensive production testing to help deliver consistent signal performance and reliable emissions control service.

• Heated oxygen sensor for downstream right placement
• Specific fit design for direct replacement installation
• 4-wire configuration with 24.75 in. wiring harness length
• 18 mm threaded mounting type
• Built for OE-style fit, form, and function

Detailed Product Overview

NTK part number 25166 is a heated, threaded oxygen sensor with a specific fit design and 4-wire construction. It is intended for downstream right B1S2 applications on 1999-2002 Hyundai Sonata, 2001-2002 Hyundai Santa Fe, 2001-2002 Kia Optima, and 2001-2002 Kia Magentis. This sensor cross-references DENSO Auto Parts 234-4432 for the same application.

For buyers searching for a direct fit downstream oxygen sensor for Hyundai Sonata, Kia Optima, or Hyundai Santa Fe applications, NTK 25166 provides the correct OE-style configuration for the listed vehicles. The direct fit design helps maintain the original sensor location and connector style expected for these emissions systems.

Common Issues This Sensor May Address

• Check engine light related to oxygen sensor performance
• Faulty downstream right B1S2 sensor readings
• Emissions test failure caused by a worn sensor
• Slow or inaccurate air-fuel monitoring feedback
• Replacement need after sensor aging or contamination

Installation Notes and Tips

Verify the vehicle’s year, make, model, and downstream right B1S2 position before ordering. Confirm the 18 mm threaded mounting style and 4-wire harness layout match the original sensor. This part is listed for 2001-2002 Hyundai Santa Fe, 1999-2002 Hyundai Sonata, 2001-2002 Kia Magentis, and 2001-2002 Kia Optima in the specified downstream right location.

Use the original routing path for the 24.75 in. harness and inspect the connector, exhaust threads, and surrounding wiring before installation. For best results, compare the old sensor’s connector and mounting details to the replacement part number 25166 before service.

Quality Assurance

NTK is a major oxygen sensor manufacturer with OE application coverage and extensive manufacturing test procedures. Part number 25166 is produced to meet or exceed OE specifications for the listed applications, supporting dependable emissions-system service on Hyundai and Kia vehicles.