{"product_id":"o2-oxygen-sensor-upstream-downstream-for-gmc-yukon-2015-2018-5-3l-6-2l","title":"O2 Oxygen Sensor Upstream Downstream for GMC Yukon (2015-2018) 5.3L, 6.2L","description":"\u003ch2 style=\"font-size: clamp(18px, 3vw, 21px); margin-bottom: 15px; line-height: 1.3;\"\u003eDirect-Fit Complete Upstream and Downstream O2 Sensor Kit for 2015-2018 GMC Yukon (K2XX)\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e The 4-piece oxygen sensor kit monitors pre- and post-catalytic exhaust gas oxygen concentrations on the 2015-2018 GMC Yukon to optimize closed-loop fuel trim mapping and preserve catalytic converter efficiency.\u003c\/p\u003e\n\n\u003ch3\u003eThe Stock GMC Yukon Sensor Degradation\u003c\/h3\u003e\n\u003cp\u003eFactory oxygen sensors on the \u003cstrong\u003eK2XX\u003c\/strong\u003e platform endure extreme thermal cycling, carbon deposits, and oil vapor contamination common to high-mileage \u003cstrong\u003eEcoTec3 L83 \/ L86\u003c\/strong\u003e direct-injection engines. Over time, OEM zirconia elements lose response speed, causing sluggish switching ratios between rich and lean states. This slow signal feedback degrades short-term fuel trim (STFT) accuracy, delays closed-loop engine management, triggers P0135\/P0141 heater circuit trouble codes, and leads to unburned hydrocarbon accumulation that rapidly degrades catalytic substrates.\u003c\/p\u003e\n\n\u003ch3\u003eThe Engineering Solution\u003c\/h3\u003e\n\u003cp\u003eThis 4-sensor replacement kit features high-temperature planar ceramic sensing elements engineered for rapid light-off times and precise lambda detection. Enclosed in double-laser-welded stainless steel bodies, each sensor resists vibration, thermal shock, and silicone poisoning. Factory-correct wiring harnesses, pre-pinned weather-pack terminal connectors, and OE-matched lead lengths ensure direct plug-and-play installation without cutting or splicing, restoring stoichiometric 14.7:1 air-fuel ratios, cold-start efficiency, and steady idle stability across both banks.\u003c\/p\u003e\n\n\u003ch3\u003eWhat's Included\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e2 x 234-4940 Upstream Oxygen Sensors\u003c\/li\u003e\n  \u003cli\u003e2 x 234-4974 Downstream Oxygen Sensors\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;\"\u003e2015-2018 GMC Yukon\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;\"\u003eEcoTec3 5.3L (L83), 6.2L (L86) \/ K2XX\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;\"\u003e355-420 hp \/ 383-460 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;\"\u003e234-4940, 234-4974, 12657188, 12659516, 234-8081, 234-8088, 12627139, 12643707, 12643708, 12645561, 12655677, 12655678, 12661898, 12665162, 12666612, 12666673, 55569902, 21074, 21075, 21579, 21581, 234-4763, 2344763, 2344940, 2344974, 234-8052, 2348052\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\u003e2015-2018 GMC Yukon 5.3L V8 (EcoTec3 L83)\u003c\/li\u003e\n  \u003cli\u003e2015-2018 GMC Yukon 6.2L V8 (EcoTec3 L86)\u003c\/li\u003e\n  \u003cli\u003e2015-2018 GMC Yukon XL 5.3L V8 (EcoTec3 L83)\u003c\/li\u003e\n  \u003cli\u003e2015-2018 GMC Yukon XL 6.2L V8 (EcoTec3 L86)\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 K2XX Yukon?\u003c\/h4\u003e\n\u003cp\u003eYes, this is a direct fit for the 2015-2018 GMC Yukon equipped with the \u003cstrong\u003e5.3L L83\u003c\/strong\u003e or \u003cstrong\u003e6.2L L86\u003c\/strong\u003e EcoTec3 engine. Verify harness pin count and engine displacement prior to installation.\u003c\/p\u003e\n\n\u003ch4\u003eShould these sensors be replaced individually or as a complete axle\/engine set?\u003c\/h4\u003e\n\u003cp\u003eReplacing upstream and downstream sensors simultaneously across Bank 1 and Bank 2 prevents false delta readings between pre- and post-catalyst feedback loops.\u003c\/p\u003e\n\n\u003ch3\u003eThe GMC Heavy-Duty Reliability Standard\u003c\/h3\u003e\n\u003cp\u003eFull-size truck and SUV platforms operating under heavy towing loads demand precise AFR calibration; these direct-fit sensors maintain exhaust monitoring integrity under sustained high-exhaust-gas temperatures (EGTs) without dropping communication with the ECM.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":67551276564728,"sku":"DS-EDW2IHLSE","price":79.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0800\/1290\/2648\/files\/o2-oxygen-sensor-upstream-downstream-for-gmc-yukon-2015-2018-5-3l-6-2l-1.jpg?v=1790794337","url":"https:\/\/performancechiptuning.com\/products\/o2-oxygen-sensor-upstream-downstream-for-gmc-yukon-2015-2018-5-3l-6-2l","provider":"Performance Chip Tuning","version":"1.0","type":"link"}