{"product_id":"ntk-21577-oxygen-sensor-upstream","title":"NTK 21577 Oxygen Sensor - Upstream","description":"\u003ch2\u003eDirect-Fit Oxygen Sensor\u003c\/h2\u003e\u003cp\u003eNTK 21577 is a specific-fit heated oxygen sensor built for direct replacement applications. It uses a threaded mounting design, a 4-wire configuration, and a 20.75-inch harness for a clean OE-style installation.\u003c\/p\u003e\u003ch2\u003eKey Features\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eSpecific-fit oxygen sensor for direct replacement service\u003c\/li\u003e\n\u003cli\u003eHeated sensor design for faster operating response\u003c\/li\u003e\n\u003cli\u003e4-wire construction for signal and heater circuit operation\u003c\/li\u003e\n\u003cli\u003eThreaded mounting type for secure installation\u003c\/li\u003e\n\u003cli\u003e20.75-inch wiring harness length\u003c\/li\u003e\n\u003cli\u003e18 mm thread diameter\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eDetailed Description\u003c\/h2\u003e\u003cp\u003eNTK 21577 is a direct fit oxygen sensor engineered for upstream air\/fuel ratio monitoring. It is listed for 2021 Buick Encore and 2021 Chevrolet Trax, along with 2011-2020 Chevrolet Cruze, Chevrolet Sonic, Chevrolet Volt, Chevrolet Trax, Buick Encore, and Cadillac ELR applications. This part cross-references Bosch 16734 and DENSO Auto Parts 234-4529 for the same application. As part of the NTK Direct Fit Oxygen Sensor line, it reflects NTK's OE-focused approach to sensor coverage and application-specific fitment. The NTK 21577 supports accurate exhaust feedback in vehicles such as the Chevrolet Cruze and Buick Encore when the original sensor needs replacement.\u003c\/p\u003e\u003ch2\u003eCommon Issues Addressed\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eFault codes related to oxygen sensor performance\u003c\/li\u003e\n\u003cli\u003eDelayed or unstable air\/fuel ratio feedback\u003c\/li\u003e\n\u003cli\u003eRough idle or drivability concerns tied to upstream sensor output\u003c\/li\u003e\n\u003cli\u003eEmissions test failures caused by a worn sensor\u003c\/li\u003e\n\u003cli\u003eReplacement needs for a damaged threaded sensor assembly\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\u003cp\u003eVerify the upstream position and bank\/sensor application before ordering. Confirm the 18 mm thread diameter, 4-wire layout, and harness length against the original part. Use the vehicle's service procedure for removal and installation to ensure proper sensor seating and connector routing.\u003c\/p\u003e\u003ch2\u003eQuality Assurance\u003c\/h2\u003e\u003cp\u003eNTK tests oxygen sensors during manufacturing to meet or exceed OE specifications. The brand is part of the NGK family and is recognized as a major OE oxygen sensor supplier.\u003c\/p\u003e","brand":"NTK","offers":[{"title":"Default Title","offer_id":53555990167733,"sku":"BFPZ-21577","price":78.55,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0628\/1442\/1173\/files\/NO_21577_Fro.jpg?v=1792390258","url":"https:\/\/www.partcatalog.com\/products\/ntk-21577-oxygen-sensor-upstream","provider":"PartCatalog","version":"1.0","type":"link"}