NTK 25239 Oxygen Sensor - Upstream Left

Direct-Fit Oxygen Sensor

NTK Direct Fit Oxygen Sensor 25239 is a specific-fit heated oxygen sensor built for emission control service. It is engineered for threaded installation and uses a 4-wire design with a 9.84 wiring harness length and 18.000 thread diameter.

Compatible with 2015-2017 Kia K900, upstream left. This part cross-references 392103C590 for the same application.

• Heated oxygen sensor for precise exhaust feedback
• Specific-fit design for direct replacement service
• Threaded mounting for a secure sensor installation
• 4-wire configuration with integrated harness length

Application Details

Fits 2015-2017 Kia K900, upstream left, bank 2 sensor 1. The NTK 25239 is part of the Direct Fit Oxygen Sensor line, which focuses on application-specific coverage and OE-style fit, form, and function. NTK is known for oxygen sensor manufacturing within the NGK family and applies ceramic technology control from raw material through finished production.

Common Issues Addressed

• Faulty oxygen sensor readings that can trigger emissions-related trouble codes
• Slow sensor response affecting fuel control and exhaust monitoring
• Wiring or connector wear on an aging sensor assembly
• Replacement needs for a threaded, heated upstream oxygen sensor

Installation Notes and Quality

Verify the connector style, thread diameter, harness length, and upstream left location before installation. Confirm the vehicle application by part number 25239 and the OE cross-reference 392103C590 to ensure the correct emission control sensor is selected.

Quality Assurance

NTK tests oxygen sensors during manufacturing to meet or exceed OE specifications. The brand’s OE-supplier background and ceramic manufacturing expertise support consistent fit and reliable performance.