{"product_id":"oxygen-sensors-for-nissan-maxima-altima-2002-2003-3-5l-upstream","title":"Oxygen Sensors for Nissan Maxima Altima (2002-2003) 3.5L Upstream","description":"\u003ch2\u003ePrecision-Calibrated Upstream Oxygen Sensor for 2002-2003 Nissan Maxima, Altima\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e The Upstream Oxygen Sensor monitors pre-catalyst exhaust gas oxygen content to provide instant air-fuel ratio feedback to the ECM, optimizing fuel trims and engine efficiency on 2002-2003 Nissan Maxima and Altima models.\u003c\/p\u003e\n\n\u003ch3\u003eThe Stock Nissan Maxima, Altima O2 Sensor Degradation\u003c\/h3\u003e\n\u003cp\u003eFactory upstream sensors on the \u003cstrong\u003eVQ35DE\u003c\/strong\u003e platform endure extreme thermal cycling in the exhaust manifold, causing the internal zirconia ceramic sensing element to degrade over time. Exhaust soot, oil vapor blow-by, and lead or silicone contaminants glaze the porous platinum coating. This degradation increases signal latency and electrical resistance, delivering sluggish millivolt readings to the ECM. The result is erratic closed-loop feedback, rough idle, poor cold-start fueling, elevated emissions, and diagnostic trouble codes such as P0130 through P0135.\u003c\/p\u003e\n\n\u003ch3\u003eThe Engineering Solution\u003c\/h3\u003e\n\u003cp\u003eThis direct-replacement upstream oxygen sensor features an integrated ceramic heater element and a dual-layer protective planar zirconia core housed in high-grade stainless steel. Precision laser welding protects the internal sensing components from severe vibration and high exhaust gas temperatures. Calibrated to match OEM switching speeds, it accurately communicates stoichiometric air-fuel variance back to the engine control module. This restores proper fuel delivery curves, eliminates rich or lean conditions, and recovers lost throttle response without wire cutting or pinning.\u003c\/p\u003e\n\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003ctable width=\"100%\" style=\"border-collapse: collapse; border: 1px solid #e0e0e0; font-size: 14px; margin-bottom: 20px;\"\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;\"\u003e2002-2003 Nissan Maxima, Altima\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;\"\u003e\n\u003cstrong\u003eVQ35DE\u003c\/strong\u003e (3.5L V6) \/ \u003cstrong\u003eA33B\u003c\/strong\u003e, \u003cstrong\u003eL31\u003c\/strong\u003e\n\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;\"\u003e240-255 hp \/ 246 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;\"\u003eN\/A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eCompatibility\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e2002-2003 Nissan Maxima 3.5L V6 (\u003cstrong\u003eA33B\u003c\/strong\u003e Chassis) - Upstream \/ Pre-Catalyst\u003c\/li\u003e\n  \u003cli\u003e2002-2003 Nissan Altima 3.5L V6 (\u003cstrong\u003eL31\u003c\/strong\u003e Chassis) - Upstream \/ Pre-Catalyst\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eDoes this fit the A33B and L31 Maxima, Altima?\u003c\/strong\u003e\u003cbr\u003e Yes, this is a direct fit for the upstream exhaust positions on 2002-2003 Nissan Maxima and Altima models equipped with the \u003cstrong\u003eVQ35DE\u003c\/strong\u003e 3.5L engine.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill installing this sensor resolve an active O2 heater or lean code?\u003c\/strong\u003e\u003cbr\u003e Yes, replacing a degraded sensor restores the heater circuit and closed-loop feedback, clearing associated CEL codes once drive cycles complete.\u003c\/p\u003e\n\n\u003ch3\u003eThe Nissan Performance Caliber\u003c\/h3\u003e\n\u003cp\u003eEngineered to withstand the thermal demands of Nissan's high-flow VQ-series V6, ensuring crisp throttle response, optimized fuel delivery, and uncompromised engine reliability under all operating loads.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":50511220539640,"sku":"DS-EPYH6Y1LQ","price":69.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0800\/1290\/2648\/files\/oxygen-sensors-for-nissan-maxima-altima-2002-2003-3-5l-upstream-1.jpg?v=1789411492","url":"https:\/\/performancechiptuning.com\/products\/oxygen-sensors-for-nissan-maxima-altima-2002-2003-3-5l-upstream","provider":"Performance Chip Tuning","version":"1.0","type":"link"}