{"product_id":"ntk-25539-oxygen-sensor-downstream-or-upstream","title":"NTK 25539 Oxygen Sensor - Downstream or Upstream","description":"\u003ch2\u003eDirect-Fit Oxygen Sensor for Volkswagen Applications\u003c\/h2\u003e\u003cp\u003eNTK 25539 is a specific-fit heated oxygen sensor built for select Volkswagen applications. It uses a threaded mounting design and a 4-wire configuration to match the original sensor layout for accurate air-fuel monitoring.\u003c\/p\u003e\u003cp\u003eAs part of NTK's Direct Fit Oxygen Sensor line, this unit is engineered for OE-style fit, form, and function. The 24.5-inch harness length and 18 mm thread diameter support proper routing and installation on covered Volkswagen Golf, Jetta, Cabrio, Corrado, and Passat applications.\u003c\/p\u003e\u003ch2\u003eKey Features\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eHeated oxygen sensor for precise exhaust feedback\u003c\/li\u003e\n\u003cli\u003eSpecific-fit design for direct replacement use\u003c\/li\u003e\n\u003cli\u003eThreaded mounting style with 18 mm thread diameter\u003c\/li\u003e\n\u003cli\u003e4-wire sensor configuration\u003c\/li\u003e\n\u003cli\u003e24.5-inch wiring harness length\u003c\/li\u003e\n\u003cli\u003eOE-equivalent design for covered Volkswagen applications\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eDetailed Description\u003c\/h2\u003e\u003cp\u003eNTK 25539 is a direct-fit oxygen sensor for select Volkswagen Golf, Jetta, Cabrio, Corrado, and Passat models. Fitment includes upstream and downstream locations depending on the application, with notes for Bank 1 Sensor 1 and Bank 1 Sensor 2 coverage where specified. This part number is listed for 1992-1999 Volkswagen applications and is built to match the original sensor style used on the vehicle.\u003c\/p\u003e\u003cp\u003eNTK's sensor program is backed by its role as a major original equipment oxygen sensor manufacturer. The brand uses ceramic-focused manufacturing technology and tests sensors during production to help maintain OE-level quality and reliability. This makes NTK 25539 a practical choice when replacing a worn sensor on a Volkswagen Golf or Jetta, or on other covered Volkswagen models that require the same direct-fit configuration. Part number 25539 is also referenced by cross numbers such as Bosch 13267 and Delphi ES10333 for the same application.\u003c\/p\u003e\u003ch2\u003eWhat This Part Helps Address\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eCheck engine light caused by oxygen sensor failure\u003c\/li\u003e\n\u003cli\u003eIncorrect air-fuel ratio readings\u003c\/li\u003e\n\u003cli\u003eSlow or unstable sensor response\u003c\/li\u003e\n\u003cli\u003eExhaust feedback issues affecting engine management\u003c\/li\u003e\n\u003cli\u003eFitment problems from a mismatched sensor design\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eInstallation Notes and Tips\u003c\/h2\u003e\u003cp\u003eVerify the vehicle's year, model, engine code, and sensor position before ordering. This part is specific fit, so confirm whether the application calls for upstream or downstream placement and review the chassis break notes listed in the fitment data. Use the existing connector routing and harness length as a reference during installation.\u003c\/p\u003e\u003ch2\u003eQuality Assurance\u003c\/h2\u003e\u003cp\u003eNTK states that its oxygen sensors are extensively tested during manufacturing to meet or exceed OE specifications. The Direct Fit Oxygen Sensor line is built to provide OE-style fit, form, and function for covered applications.\u003c\/p\u003e","brand":"NTK","offers":[{"title":"Default Title","offer_id":53731437478069,"sku":"BFPZ-25539","price":87.87,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0628\/1442\/1173\/files\/NO_25539_Fro.jpg?v=1794296241","url":"https:\/\/www.partcatalog.com\/products\/ntk-25539-oxygen-sensor-downstream-or-upstream","provider":"PartCatalog","version":"1.0","type":"link"}