{"product_id":"o2-oxygen-sensor-upstream-downstream-for-mazda-6-2003-2004-2-3l","title":"O2 Oxygen Sensor Upstream Downstream for Mazda 6 (2003-2004) 2.3L","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 2003-2004 Mazda 6 (GG)\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e This matched upstream and downstream O2 sensor kit monitors exhaust oxygen on the 2003-2004 Mazda 6 (\u003cstrong\u003eGG\u003c\/strong\u003e) \u003cstrong\u003eL3-VE 2.3L I4\u003c\/strong\u003e to regulate closed-loop fueling and catalyst efficiency.\u003c\/p\u003e\u003ch3\u003eThe Stock Mazda 6 Oxygen Sensor Failure\u003c\/h3\u003e\u003cp\u003eOn the \u003cstrong\u003eGG\u003c\/strong\u003e chassis with the \u003cstrong\u003eL3-VE 2.3L DOHC I4\u003c\/strong\u003e, factory oxygen sensors endure severe exhaust heat soak, thermal cycling, and carbon fouling over time. The internal zirconia sensing element loses switching speed between rich and lean states, while the heater circuit frequently suffers open-circuit burnout. Degraded exhaust feedback forces open-loop fueling in the PCM and triggers fault codes such as \u003cstrong\u003eP0130\u003c\/strong\u003e, \u003cstrong\u003eP0135\u003c\/strong\u003e, or \u003cstrong\u003eP0141\u003c\/strong\u003e.\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 Logs \u003cstrong\u003eP0130\u003c\/strong\u003e, \u003cstrong\u003eP0135\u003c\/strong\u003e, \u003cstrong\u003eP0141\u003c\/strong\u003e, or false \u003cstrong\u003eP0420\u003c\/strong\u003e catalyst codes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFuel Trim Drift:\u003c\/strong\u003e Sluggish voltage switching causes lean\/rich imbalance like \u003cstrong\u003eP0171\u003c\/strong\u003e and rough idle.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePerformance \u0026amp; Emissions Loss:\u003c\/strong\u003e Over-fueling reduces MPG, dulls throttle response, and fails smog checks.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eThe Direct-Fit Dual-Position Oxygen Sensor Solution\u003c\/h3\u003e\u003cp\u003eReplacing both sensors as a matched pair restores balanced upstream fueling control and downstream catalyst monitoring on the \u003cstrong\u003eGG\u003c\/strong\u003e exhaust system. Each direct-fit unit uses a zirconia ceramic element in a corrosion-resistant stainless housing with calibrated heater resistance for fast cold-start light-off. Factory-terminated OEM-style connectors match interchange numbers \u003cstrong\u003e234-4399\u003c\/strong\u003e and \u003cstrong\u003e234-4393\u003c\/strong\u003e, delivering plug-and-play electrical signal output without cutting or splicing.\u003c\/p\u003e\u003ch3\u003eWhat's Included\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e1 Upstream Oxygen Sensor\u003c\/li\u003e\n\u003cli\u003e1 Downstream Oxygen Sensor\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;\"\u003e2003-2004 Mazda 6\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;\"\u003eL3-VE 2.3L I4 \/ GG\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;\"\u003eHeated 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\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;\"\u003eReplaces OEM Part #\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e234-4399, 234-4393\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003c\/div\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e2003-2004 Mazda 6 2.3L I4 (1 Upstream \u0026amp; 1 Downstream)\u003c\/li\u003e\n\u003cli\u003e2005 Mazda 6 2.3L California with Manual Transmission Only (Confirm engine before ordering)\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions \u0026amp; Fitment Warnings\u003c\/h3\u003e\u003ch4\u003eDoes this fit the GG 6?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eYes.\u003c\/strong\u003e Fits 2003-2004 Mazda 6 \u003cstrong\u003eL3-VE 2.3L I4\u003c\/strong\u003e models. \u003cstrong\u003eExcludes V6 trims; 2005 fitment covers California 2.3L manual-transmission models only.\u003c\/strong\u003e\u003c\/p\u003e\u003ch4\u003eWill this clear P0135 or P0420 codes?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eYes, if sensors are faulty.\u003c\/strong\u003e Fresh \u003cstrong\u003e234-4399\u003c\/strong\u003e and \u003cstrong\u003e234-4393\u003c\/strong\u003e units restore heater and switching response, clearing \u003cstrong\u003eP0135\u003c\/strong\u003e\/\u003cstrong\u003eP0141\u003c\/strong\u003e and false \u003cstrong\u003eP0420\u003c\/strong\u003e codes.\u003c\/p\u003e\u003ch4\u003eIs wiring modification required?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eNo.\u003c\/strong\u003e Direct-fit plugs install cleanly; chase bung threads and torque to OEM specification.\u003c\/p\u003e\u003ch3\u003eThe Mazda Precision Standard\u003c\/h3\u003e\u003cp\u003eBuilt for the \u003cstrong\u003eGG\u003c\/strong\u003e platform, this matched sensor set restores closed-loop fuel control, throttle response, and CEL-free emissions compliance.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":68119447142648,"sku":"DS-E3S7U6C78","price":45.95,"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-6-2003-2004-2-3l-1.jpg?v=1794721888","url":"https:\/\/performancechiptuning.com\/products\/o2-oxygen-sensor-upstream-downstream-for-mazda-6-2003-2004-2-3l","provider":"Performance Chip Tuning","version":"1.0","type":"link"}