{"product_id":"o2-oxygen-sensor-upstream-downstream-for-gmc-sierra-2003-2007-5-3l","title":"O2 Oxygen Sensor Upstream Downstream for GMC Sierra (2003-2007) 5.3L","description":"\u003ch2 style=\"font-size: clamp(18px, 3vw, 21px); margin-bottom: 15px; line-height: 1.3;\"\u003eDirect-Fit Upstream \u0026amp; Downstream O2 Sensor Kit for 2003-2007 GMC Sierra (GMT800)\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e This 4-piece oxygen sensor kit replaces upstream and downstream sensors on the 2003-2007 GMC Sierra 1500 \u003cstrong\u003e5.3L V8\u003c\/strong\u003e to restore closed-loop fuel trim control.\u003c\/p\u003e\u003ch3\u003eThe Stock GMC Sierra O2 Sensor Failure\u003c\/h3\u003e\u003cp\u003eOn the \u003cstrong\u003eGMT800\u003c\/strong\u003e platform powered by the \u003cstrong\u003eLM7 \/ L59 5.3L V8\u003c\/strong\u003e, factory oxygen sensors endure extreme thermal cycling and exhaust moisture. Carbon soot and oil ash glaze the zirconia tip while internal heater elements burn out, triggering \u003cstrong\u003eP0135\u003c\/strong\u003e, \u003cstrong\u003eP0155\u003c\/strong\u003e, \u003cstrong\u003eP0141\u003c\/strong\u003e, or \u003cstrong\u003eP0161\u003c\/strong\u003e fault codes. Degraded switching speed forces the ECM into rich open-loop fueling, hurting fuel economy and overloading catalytic converters.\u003c\/p\u003e\u003ch4\u003eCommon Symptoms of a Failing OEM Oxygen Sensor\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCheck Engine Light \/ DTCs:\u003c\/strong\u003e Triggers \u003cstrong\u003eP0135\u003c\/strong\u003e, \u003cstrong\u003eP0155\u003c\/strong\u003e, \u003cstrong\u003eP0141\u003c\/strong\u003e, \u003cstrong\u003eP0161\u003c\/strong\u003e, or lean codes \u003cstrong\u003eP0171\/P0174\u003c\/strong\u003e.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSluggish Voltage Switching:\u003c\/strong\u003e Causes rough idle, hesitation, and erratic fuel trims.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEmissions \u0026amp; Economy Loss:\u003c\/strong\u003e Rich running wastes fuel and triggers false \u003cstrong\u003eP0420\/P0430\u003c\/strong\u003e codes.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eThe Direct-Fit Heated Zirconia O2 Solution\u003c\/h3\u003e\u003cp\u003eThis matched 4-sensor kit provides two upstream and two downstream units engineered for the \u003cstrong\u003eGMT800\u003c\/strong\u003e \u003cstrong\u003e5.3L V8\u003c\/strong\u003e. Each sensor uses a fast-heating ceramic element inside a 4-wire zirconia core with a protective vented shield for rapid closed-loop response. Factory-style OEM connectors and direct-fit harness lengths eliminate wiring splices, restoring accurate 14.7:1 stoichiometric air-fuel feedback and reliable downstream catalyst efficiency monitoring under all operating loads.\u003c\/p\u003e\u003ch3\u003eWhat's Included\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e2 Upstream Oxygen Sensors\u003c\/li\u003e\n\u003cli\u003e2 Downstream Oxygen Sensors\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\u003cdiv style=\"overflow-x: auto; margin-bottom: 20px;\"\u003e\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;\"\u003e2003-2007 GMC Sierra\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;\"\u003eLM7 \/ L59 5.3L V8 \/ GMT800\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;\"\u003eSensor Architecture\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e4-Wire Heated Zirconia \/ Upstream \u0026amp; Downstream\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eInstallation Type\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003eDirect Bolt-On OEM Replacement (No Cutting or Welding)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003c\/div\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e2003-2007 GMC Sierra 1500 (5.3L V8)\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions \u0026amp; Fitment Warnings\u003c\/h3\u003e\u003ch4\u003eDoes this fit the GMT800 Sierra?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eYes.\u003c\/strong\u003e This is a direct fit for the 2003-2007 GMC Sierra equipped with the \u003cstrong\u003e5.3L V8 (LM7\/L59)\u003c\/strong\u003e engine. \u003cstrong\u003eExcludes 4.3L, 4.8L, 6.0L, and 2008+ trucks; confirm engine before ordering.\u003c\/strong\u003e\u003c\/p\u003e\u003ch4\u003eWill this clear P0135\/P0155 or P0420 codes?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eYes, for sensor faults.\u003c\/strong\u003e Replacing all four sensors clears \u003cstrong\u003eP0135\/P0141\/P0155\/P0161\u003c\/strong\u003e heater and response codes, though damaged converters still trigger \u003cstrong\u003eP0420\/P0430\u003c\/strong\u003e.\u003c\/p\u003e\u003ch4\u003eIs wiring or splicing required for installation?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eNo.\u003c\/strong\u003e Direct-fit OEM connectors plug directly into factory harnesses; clean bung threads and torque sensors securely.\u003c\/p\u003e\u003ch3\u003eThe GMC Heavy-Duty Standard\u003c\/h3\u003e\u003cp\u003eEngineered for towing durability and high-mileage reliability, this matched O2 kit keeps your \u003cstrong\u003eGMT800\u003c\/strong\u003e Sierra operating efficiently. Expect crisp throttle response, steady fuel economy, and CEL-free emissions performance.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":68116018594040,"sku":"DS-E280PSHAO","price":37.95,"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-sierra-2003-2007-5-3l-1.jpg?v=1794710341","url":"https:\/\/performancechiptuning.com\/products\/o2-oxygen-sensor-upstream-downstream-for-gmc-sierra-2003-2007-5-3l","provider":"Performance Chip Tuning","version":"1.0","type":"link"}