{"product_id":"a-premium-o2-oxygen-sensor-downstream-4-wire-heated-direct-fit-for-chevy-gmc-buick-hummer-400mm","title":"A-Premium O2 Oxygen Sensor Downstream 4-Wire Heated — Direct-Fit for Chevy, GMC, Buick, Hummer (400mm)","description":"\u003cp\u003e\u003cstrong\u003eThe A-Premium O2 oxygen sensor is a direct-fit downstream, 4-wire heated replacement designed to restore accurate exhaust oxygen readings for compatible GM and related vehicles.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThis premium aftermarket sensor replaces worn or failing downstream (post-catalytic) oxygen sensors on a range of Chevrolet, GMC, Buick, Hummer, Pontiac, Saab and Saturn models. Built with a heated sensing element and a threaded mounting style, the unit matches OE electrical connections and dimensions (4 wires, 400 mm overall length) so it installs without modification. Use the reference part numbers to confirm compatibility with your vehicle.\u003c\/p\u003e\n\n\u003ch3\u003eWhich vehicles will this A-Premium O2 sensor fit?\u003c\/h3\u003e\n\u003cp\u003eThis oxygen sensor is specified as a downstream (post-cat) unit and fits many GM-family models across the late 2000s and early 2010s. Match the engine, model year and bank\/sensor position (B1S2 or B2S2) listed for each vehicle to ensure correct fitment before ordering.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eBuick: Enclave 2008 3.6L, LaCrosse 2010 2.4L, Lucerne 2009–2011 3.9L, Rainier 2007 4.2L\u003c\/li\u003e\n  \u003cli\u003eChevrolet: Captiva Sport, Colorado, Equinox, Malibu, Orlando, Trailblazer (years\/engines listed in product details)\u003c\/li\u003e\n  \u003cli\u003eGMC\/Hummer\/Pontiac\/Saturn\/Saab\/Isuzu: Multiple models including Acadia, Canyon, Envoy, Terrain, H3\/H3T, G6, Solstice, Aura, Outlook, Sky, Vue, 9-7x, Ascender, i-290, i-370\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow does the sensor's specification affect performance and installation?\u003c\/h3\u003e\n\u003cp\u003eThe heated 4-wire design speeds warm-up so the engine control module receives accurate oxygen data sooner after startup. Threaded mounting and a male connector mirror factory parts, simplifying installation and reducing the need for adaptors or rewiring.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eHeated element: faster operating temperature for reliable readings\u003c\/li\u003e\n  \u003cli\u003e4 wires: separate heater circuit plus signal\/ground for stable data\u003c\/li\u003e\n  \u003cli\u003e400 mm length: engineered to reach factory harness routing without strain\u003c\/li\u003e\n  \u003cli\u003eThreaded mount: installs into original bung like OEM sensors\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat reference numbers and part details should I check before buying?\u003c\/h3\u003e\n\u003cp\u003eCompare the reference numbers and physical specs to the part you are replacing. The listing includes multiple OEM cross-references to help identify the correct downstream sensor for your vehicle.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eReference numbers: 12599204, 12604538, 12617907, 12597947, 12618010, 12618012, 250-24708, 25024708\u003c\/li\u003e\n  \u003cli\u003eConnector gender: male — matches factory harness receptacle\u003c\/li\u003e\n  \u003cli\u003ePackaging: single sensor per box for one-to-one replacement\u003c\/li\u003e\n  \u003cli\u003eMounting type: threaded to fit factory exhaust bungs\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this replacement sensor for?\u003c\/p\u003e\n\u003cp\u003eThis A-Premium downstream oxygen sensor is intended for DIY mechanics, independent repair shops and fleet technicians replacing a failing post-catalytic O2 sensor on compatible GM-based vehicles. It’s suitable when diagnostics report a downstream sensor fault, when you need a reliable one-to-one OE-style replacement, or when restoring correct emissions monitoring after exhaust repairs. Always verify vehicle year, engine size and bank\/sensor position against the fitment list and reference numbers to ensure proper selection.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Is this sensor upstream or downstream?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: This A-Premium unit is a downstream (post-catalytic) oxygen sensor intended for the B1S2\/B2S2 positions listed.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Will the connector fit my vehicle harness?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: The sensor uses a male connector with a 4-wire harness to match factory female sockets on compatible models.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"A-Premium","offers":[{"title":"Default Title","offer_id":55166113120599,"sku":"B07MMHT1ZP","price":35.09,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1050\/1524\/7191\/files\/a-premium-o2-front-view.jpg?v=1790363331","url":"https:\/\/britishgarage.co.uk\/products\/a-premium-o2-oxygen-sensor-downstream-4-wire-heated-direct-fit-for-chevy-gmc-buick-hummer-400mm","provider":"British Garage","version":"1.0","type":"link"}