{"product_id":"o2-oxygen-sensor-upstream-downstream-for-gmc-sierra-3500-hd-2008-2011-6-0l","title":"O2 Oxygen Sensor Upstream Downstream for GMC Sierra 3500 HD (2008-2011) 6.0L","description":"\u003ch2 style=\"font-size: clamp(18px, 3vw, 21px); margin-bottom: 15px; line-height: 1.3;\"\u003eDirect-Fit Replacement Oxygen Sensor Kit for 2008-2011 GMC Sierra (GMT900)\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e The 4-piece oxygen sensor kit restores closed-loop AFR feedback and catalytic monitoring on the 2008-2011 Sierra to eliminate check engine lights, recover lost fuel economy, and stabilize engine idle.\u003c\/p\u003e\n\n\u003ch3\u003eThe Stock GMC Sierra Sensor Degradation\u003c\/h3\u003e\n\u003cp\u003eExhaust gas exposure on high-mileage \u003cstrong\u003eGMT900\u003c\/strong\u003e work trucks subjects factory oxygen sensors to extreme thermal cycling, sulfur deposits, and carbon fouling. Over time, internal zirconia ceramic elements lose response fidelity, generating sluggish switching voltages. This sensor drift triggers DTC trouble codes (such as P0135, P0155, or P0420), forces the \u003cstrong\u003eVortec 6.0L\u003c\/strong\u003e PCM into rich default fueling trims, and increases catalytic converter operating temperatures under heavy payload demands.\u003c\/p\u003e\n\n\u003ch3\u003eThe Engineering Solution\u003c\/h3\u003e\n\u003cp\u003eEngineered to direct OEM specifications, this 4-piece sensor assembly features laser-welded stainless steel bodies and planar ceramic sensing elements for rapid heater circuit activation. Pre-applied high-temperature anti-seize on the threads prevents exhaust bung galling, while weatherproof OEM-spec terminal pinouts ensure factory harness connectivity. By refreshing both upstream wideband\/narrowband regulation and downstream catalyst efficiency monitoring simultaneously, fuel mapping returns to stoichiometry across variable load curves.\u003c\/p\u003e\n\n\u003ch3\u003eWhat's Included\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e2x Upstream Oxygen Sensors\u003c\/li\u003e\n  \u003cli\u003e2x 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;\"\u003e2008-2011 GMC Sierra 3500 HD\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;\"\u003eVortec 6.0L (LY6 \/ L96) \/ GMT900\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;\"\u003e353-360 hp \/ 373-380 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;\"\u003e21546, 234-4254, 234-4407, 234-4668, 15284, 2344254, 2344668, ES20013, OS1656, OS2239, OS2240, OS2249, SG1857\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\u003e2008-2011 GMC Sierra 3500 HD 6.0L V8\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 GMT900 Sierra?\u003c\/h4\u003e\n\u003cp\u003eYes, this is a direct fit for the 2008-2011 GMC Sierra equipped with the \u003cstrong\u003eVortec 6.0L\u003c\/strong\u003e engine. Confirm your truck has the 6.0L displacement before ordering, as 6.6L Duramax diesel models utilize distinct sensor configurations.\u003c\/p\u003e\n\n\u003ch4\u003eShould I replace all four O2 sensors simultaneously?\u003c\/h4\u003e\n\u003cp\u003eYes, replacing upstream and downstream units concurrently guarantees unified response times and prevents false downstream trim error codes caused by mismatched sensor aging.\u003c\/p\u003e\n\n\u003ch3\u003eThe GMC Heavy-Duty Durability Standard\u003c\/h3\u003e\n\u003cp\u003eMaintaining accurate air-fuel management is vital for the thermal protection of heavy-duty work platforms pulling max GVWR payloads across steep grades.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":67551235965176,"sku":"DS-E6KYL6QSJ","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-sierra-3500-hd-2008-2011-6-0l-1.jpg?v=1790793791","url":"https:\/\/performancechiptuning.com\/fr\/products\/o2-oxygen-sensor-upstream-downstream-for-gmc-sierra-3500-hd-2008-2011-6-0l","provider":"Performance Chip Tuning","version":"1.0","type":"link"}