{"product_id":"o2-oxygen-sensor-upstream-downstream-for-mazda-cx-9-2011-2015-3-7l","title":"O2 Oxygen Sensor Upstream Downstream for Mazda CX-9 (2011-2015) 3.7L","description":"\u003ch2 style=\"font-size: clamp(18px, 3vw, 21px); margin-bottom: 15px; line-height: 1.3;\"\u003eDirect-Fit Complete O2 Oxygen Sensor Kit for 2011-2015 Mazda CX-9 (TB)\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e The complete upstream and downstream oxygen sensor kit replaces degraded factory lambda sensors on the 2011-2015 Mazda CX-9 to restore closed-loop air-fuel metering, resolve check engine codes, and optimize fuel economy.\u003c\/p\u003e\n\n\u003ch3\u003eThe Stock Mazda CX-9 Sensor Degradation\u003c\/h3\u003e\n\u003cp\u003eOver extended thermal cycles, the factory zirconia thimble elements inside the OEM sensors on the \u003cstrong\u003eMZI 3.7L V6\u003c\/strong\u003e suffer from silicone poisoning, exhaust carbon contamination, and internal heater circuit failure. As response times lag, the PCM relies on inaccurate voltage feedback, forcing the fuel trims excessively rich or lean. This manifests as catalyst-inefficiency trouble codes (P0420\/P0430), slow throttle tip-in, fouled spark plugs, and increased tailpipe emissions.\u003c\/p\u003e\n\n\u003ch3\u003eThe Engineering Solution\u003c\/h3\u003e\n\u003cp\u003eThis four-piece matched sensor kit provides two wideband air-fuel ratio upstream sensors and two switching downstream sensors designed specifically for the \u003cstrong\u003eTB\u003c\/strong\u003e chassis exhaust geometry. Built with high-grade planar ceramic substrates, fast-acting internal ceramic heaters, and double-laser-welded stainless steel bodies, these units resist thermal shock and mechanical vibration. Factory-pinned pigtails with weather-pack connectors allow direct plug-and-play installation into the OE harness without wire splicing or pin depinning.\u003c\/p\u003e\n\n\u003ch3\u003eWhat's Included\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e2x Upstream Oxygen Sensors (Bank 1 \u0026amp; Bank 2 Sensor 1)\u003c\/li\u003e\n  \u003cli\u003e2x Downstream Oxygen Sensors (Bank 1 \u0026amp; Bank 2 Sensor 2)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003cdiv style=\"overflow-x: auto; margin-bottom: 20px;\"\u003e\n  \u003ctable width=\"100%\" style=\"border-collapse: collapse; border: 1px solid #e0e0e0; font-size: 14px; min-width: 300px;\"\u003e\n    \u003ctr style=\"background-color: #f9f9f9;\"\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eFitment\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e2011-2015 Mazda CX-9\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eEngine \/ Chassis\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e3.7L MZI V6 (Cyclone) \/ TB\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr style=\"background-color: #f9f9f9;\"\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eStock Output\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e273 hp \/ 270 lb-ft\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eReplaces OEM Part #\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e234-4489, 234-5038, BR3Z-9G444-A, BR3Z9G444A, BE5Z9G444D, BH6Z9G444A, BL3Z9F472A, BL3Z9G472A, CA38188G1, CA3918861, CA4118861, CK4Z9G444D, DY1178, OS5578, ZZDL18861, 234-4490, 9E5Z9F472D, 2344489\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch3\u003eCompatibility\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e2011 Mazda CX-9 3.7L V6 (Sport, Touring, Grand Touring)\u003c\/li\u003e\n  \u003cli\u003e2012 Mazda CX-9 3.7L V6 (Sport, Touring, Grand Touring)\u003c\/li\u003e\n  \u003cli\u003e2013 Mazda CX-9 3.7L V6 (Sport, Touring, Grand Touring)\u003c\/li\u003e\n  \u003cli\u003e2014 Mazda CX-9 3.7L V6 (Sport, Touring, Grand Touring)\u003c\/li\u003e\n  \u003cli\u003e2015 Mazda CX-9 3.7L V6 (Sport, Touring, Grand Touring)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFrequently Asked Questions \u0026amp; Fitment Warnings\u003c\/h3\u003e\n\u003ch4\u003eDoes this fit the TB CX-9?\u003c\/h4\u003e\n\u003cp\u003eYes, this is a direct fit for the 2011-2015 Mazda CX-9 equipped with the \u003cstrong\u003e3.7L MZI V6\u003c\/strong\u003e engine. \u003cstrong\u003eDoes not fit 2007-2008 CX-9 models equipped with the earlier 3.5L engine or 2016+ second-generation 2.5T SkyActiv-G models.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003ch4\u003eDo these sensors require anti-seize compound on the threads prior to installation?\u003c\/h4\u003e\n\u003cp\u003eYes, ensure high-temperature anti-seize is applied to the sensor threads while taking strict care not to contaminate the protective perforated sensor tip.\u003c\/p\u003e\n\n\u003ch3\u003eThe Mazda Calibration Standard\u003c\/h3\u003e\n\u003cp\u003ePreserve factory powertrain drivability, throttle responsiveness, and catalytic converter longevity with precise closed-loop fueling feedback built to endure sustained operating temperatures.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":67551460327672,"sku":"DS-EI31QXVGC","price":99.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0800\/1290\/2648\/files\/o2-oxygen-sensor-upstream-downstream-for-mazda-cx-9-2011-2015-3-7l-1.jpg?v=1790796667","url":"https:\/\/performancechiptuning.com\/products\/o2-oxygen-sensor-upstream-downstream-for-mazda-cx-9-2011-2015-3-7l","provider":"Performance Chip Tuning","version":"1.0","type":"link"}