{"product_id":"engine-control-unit-by-yamaha-b42-8591a-00-00","title":"Engine Control Unit (ECU) by Yamaha","description":"\u003cdiv style=\"font-family: Arial; font-size: 12pt;\"\u003e\n\u003ch2\u003eYamaha UTV\/ATV \u0026amp; Side by Side Engine Control Module (ECM) - Available at buywitchdoctors.com\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eProduct Specifications: Genuine OEM Yamaha Engine Control Unit (ECU), Part # B42-8591A-00-00.\u003c\/strong\u003e\u003cbr\u003e\u003cbr\u003eKeep your machine running like new with a genuine Yamaha Engine Control Module (ECM) paired with premium maintenance parts from buywitchdoctors.com. The ECM is the electronic brain of your machine, reading signals from sensors and using them to control fuel delivery, ignition timing, idle, and other engine functions so the engine starts easily and runs smoothly. Because it manages so many systems at once, a healthy ECM is essential for power, fuel efficiency, and dependable starts in every kind of weather. Riders most often replace an ECM after a no-start or intermittent starting, stalling or misfiring with no other clear cause, persistent fault codes or a check engine indicator, a machine stuck in limp mode, water or moisture damage, a voltage spike from a wiring fault or jump-start, or damage from a rollover or hard trail impact.\u003c\/p\u003e\n\u003ch3\u003eWhy Choose Genuine OEM Yamaha Parts?\u003c\/h3\u003e\n\u003cp\u003eChoosing original equipment manufacturer (OEM) parts ensures your vehicle maintains its factory-standard performance, reliability, and fuel efficiency. Genuine parts eliminate the guesswork of aftermarket alternatives, offering a seamless integration with your engine's configuration.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExact-Fit Design:\u003c\/strong\u003e Matched to Yamaha's original bolt patterns, sealing surfaces, and dimensions for a leak-resistant fit.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFactory-Spec Quality:\u003c\/strong\u003e Built to the same standards as the parts installed on your machine at the factory.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePeace of Mind:\u003c\/strong\u003e Skip the trial and error of universal or aftermarket parts that may not seal or align correctly.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003ePremium Materials \u0026amp; Precision Engineering\u003c\/h3\u003e\n\u003cp\u003eCrafted to strict factory tolerances, these components utilize high-grade alloys and chemical-resistant seals. This specialized engineering withstands harsh off-road vibrations, extreme temperatures, and modern fuel additives, preventing premature wear and leaks. The ECM uses a sealed, vibration-resistant housing, protected circuitry, and corrosion-resistant connector terminals programmed specifically for your engine, so it processes sensor data accurately and keeps communicating reliably through heat, moisture, and constant trail shaking.\u003c\/p\u003e\n\u003ch3\u003eComprehensive Model Fitment (2015-Current)\u003c\/h3\u003e\n\u003cp\u003eThis genuine OEM part is engineered for a wide range of Yamaha side-by-side (SxS) and all-terrain vehicles (ATV) built from 2015 to the current model year. Please verify your series matches below:\u003c\/p\u003e\n\u003ch3\u003eUtility Task Vehicles (UTVs \/ Side-by-Sides)\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/collections\/yamaha-viking-parts\" title=\"Direct Link to all Viking Series OEM \u0026amp; Aftermarket Parts and Accessories Available at Buywitchdoctors.com\" rel=\"noopener\" target=\"_blank\"\u003eViking Series\u003c\/a\u003e:\u003c\/strong\u003e Viking 700 EPS, Viking 700 Ranch Edition, Viking VI EPS\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/collections\/yamaha-wolverine-parts\" title=\"Direct Link to all Wolverine Series OEM \u0026amp; Aftermarket Parts and Accessories Available at Buywitchdoctors.com\" rel=\"noopener\" target=\"_blank\"\u003eWolverine Series\u003c\/a\u003e:\u003c\/strong\u003e Wolverine R-Spec, Wolverine X2 850, Wolverine X4 850, Wolverine X2 1000, Wolverine RMAX2 1000 (Sport, XT-R, Limited), Wolverine RMAX4 1000\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/collections\/yamaha-yxz-parts\" title=\"Direct Link to all YXZ Series OEM \u0026amp; Aftermarket Parts and Accessories Available at Buywitchdoctors.com\" rel=\"noopener\" target=\"_blank\"\u003eYXZ Series\u003c\/a\u003e:\u003c\/strong\u003e YXZ1000R, YXZ1000R SS\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eAll-Terrain Vehicles (ATVs)\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/collections\/yamaha-yfz-parts-and-accessories\" title=\"Direct Link to all YFZ Series OEM \u0026amp; Aftermarket Parts and Accessories Available at Buywitchdoctors.com\" rel=\"noopener\" target=\"_blank\"\u003eYFZ Series\u003c\/a\u003e: \u003c\/strong\u003eYFZ50\u003cstrong\u003e, \u003c\/strong\u003eYFZ450R, YFZ450R SE\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/collections\/yamaha-raptor-parts-and-accessories\" title=\"Direct Link to all Raptor Series OEM \u0026amp; Aftermarket Parts and Accessories Available at Buywitchdoctors.com\" rel=\"noopener\" target=\"_blank\"\u003eRaptor Series\u003c\/a\u003e:\u003c\/strong\u003e Raptor 90, Raptor 110, Raptor 700, Raptor 700R, Raptor 700R SE\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/collections\/yamaha-grizzly-parts-and-accessories\" title=\"Direct Link to all Grizzly Series OEM \u0026amp; Aftermarket Parts and Accessories Available at Buywitchdoctors.com\" rel=\"noopener\" target=\"_blank\"\u003eGrizzly Series\u003c\/a\u003e:\u003c\/strong\u003e Grizzly 90, Grizzly 110, Grizzly 700 EPS, Grizzly 700 SE, Grizzly 700 XT-R\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/collections\/yamaha-kodiak-parts-and-accessories\" title=\"Direct Link to all Kodiak Series OEM \u0026amp; Aftermarket Parts and Accessories Available at Buywitchdoctors.com\" rel=\"noopener\" target=\"_blank\"\u003eKodiak Series\u003c\/a\u003e:\u003c\/strong\u003e Kodiak 450, Kodiak 450 EPS, Kodiak 700, Kodiak 700 EPS, Kodiak 700 SE\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e⚠️ \u003cstrong\u003eIMPORTANT DISCLAIMER:\u003c\/strong\u003e Fitment can vary by production date and sub-model trim. Always verify your exact original equipment part number from your vehicle's schematic or consult a certified technician before finalizing your purchase to guarantee flawless compatibility.\u003c\/p\u003e\n\u003ch3\u003eOther Popular Parts \u0026amp; Secondary Accessories\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/collections\/utv-ignition?product_type\/Ignition-Coil\/vendor\/Yamaha\" title=\"Direct Link to all Yamaha OEM Ignition Coil sold at buywitchdoctors.com\" rel=\"noopener\" target=\"_blank\"\u003eIgnition Coil\u003c\/a\u003e:\u003c\/strong\u003e The ignition coil turns battery voltage into the spark that lights the fuel, and the ECM controls when it fires. If you have a misfire or weak spark, test the coil along with the ECM before deciding which part has failed.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/collections\/utv-ignition?product_type\/CDI-Ignition\/vendor\/Yamaha\" title=\"Direct Link to all Yamaha OEM CDI Ignition sold at buywitchdoctors.com\" rel=\"noopener\" target=\"_blank\"\u003eCDI Ignition\u003c\/a\u003e:\u003c\/strong\u003e On models that use one, the CDI unit controls spark timing and works closely with the rest of the ignition system. Check the CDI and its connectors when troubleshooting a no-spark or no-start condition so you replace the right component.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/collections\/utv-sensor-tps-map-belt?product_type\/Crankshaft-Position-Sensor\/Shop-By\/Aftermarket\" target=\"_blank\" title=\"Direct Link to All Aftermarket Crankshaft Position Sensor Sold At Buywitchdoctors.com\" rel=\"noopener\"\u003eCrankshaft Position Sensor\u003c\/a\u003e:\u003c\/strong\u003e The crankshaft position sensor tells the ECM how fast the engine is turning and where the pistons are. A failing sensor can cause stalling or a no-start that looks like an ECM problem, so check it whenever you diagnose starting issues.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/collections\/utv-sensor-tps-map-belt?product_type\/Throttle-Position-Sensor\/vendor\/Yamaha\" title=\"Direct Link to all Yamaha OEM Throttle Position Sensor sold at buywitchdoctors.com\" rel=\"noopener\" target=\"_blank\"\u003eThrottle Position Sensor\u003c\/a\u003e:\u003c\/strong\u003e The throttle position sensor tells the ECM how far the throttle is open so it can adjust fuel and timing. If you have hesitation, surging, or an unstable idle, inspect this sensor and its connector along with the ECM.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eFrequently Asked Questions (FAQs)\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eQ: How do I know when my Yamaha ECM needs to be replaced, and how do I confirm the right one for my machine?\u003c\/strong\u003e\u003cbr\u003eA: Common signs include a no-start or intermittent start, stalling, misfires, stored fault codes, limp mode, or visible moisture or corrosion in the housing or connector. Because sensors, wiring, and the battery can cause the same symptoms, check those first and look for damaged wires or corroded pins before replacing the ECM. Since ECMs vary by model, model year, engine, and software, confirm the correct part and any programming or installation requirements using your Yamaha service manual or factory schematic, or contact us with your model and VIN and we will help you match it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: How do mud, water, sand, and heat affect an ECM on the trail?\u003c\/strong\u003e\u003cbr\u003eA: Moisture is the biggest threat, since water or mud that gets into connectors can cause corrosion, shorts, and erratic behavior, while heat and constant vibration can wear on electronics over time. After a wet or muddy ride, avoid aiming a pressure washer at the ECM and connectors, and check that the connectors are seated, sealed, and free of moisture or green corrosion. Follow your Yamaha service manual for correct mounting, connector sealing, and water-crossing guidance so your ECM stays protected.\u003c\/p\u003e\n\u003cp class=\"MsoNormal\" style=\"margin-top: auto; margin-bottom: auto; line-height: normal;\"\u003e\u003cb\u003e\u003cspan style=\"color: #ff2a00;\"\u003ePRO TIP: \u003c\/span\u003e\u003c\/b\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/blogs\/news\/yamaha-oem-vs-aftermarket-parts-comparison\" title=\"Direct link to Buywitchdoctors.com blog about Yamaha OEM vs. Aftermarket Parts: Are Factory Components Best for Your Trail Riding?\" rel=\"noopener\" target=\"_blank\"\u003e\u003cb\u003e\u003cspan\u003e\u003cspan style=\"color: blue;\"\u003eLearn More about Yamaha OEM vs. Aftermarket Parts\u003c\/span\u003e\u003c\/span\u003e\u003c\/b\u003e\u003c\/a\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\" style=\"margin-top: auto; margin-bottom: auto; line-height: normal;\"\u003e \u003c\/p\u003e\n\u003cp class=\"MsoNormal\" style=\"tab-stops: center 3.25in;\"\u003e\u003cb\u003e\u003cspan style=\"color: #ff2a00;\"\u003ePRO TIP:\u003c\/span\u003e\u003c\/b\u003e \u003cstrong\u003eLearn the \u003cspan style=\"color: blue;\"\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/blogs\/news\/signs-of-a-failing-cdi-ignition-module-how-to-diagnose-fix-it\" title=\"Direct link to buywitchdoctors.com blog about Signs of a Failing CDI Ignition Module? How to Diagnose \u0026amp; Fix It\" target=\"_blank\"\u003eS\u003c\/a\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/blogs\/news\/signs-of-a-failing-cdi-ignition-module-how-to-diagnose-fix-it\" rel=\"noopener\" title=\"Direct link to buywitchdoctors.com blog about Signs of a Failing CDI Ignition Module? How to Diagnose \u0026amp; Fix It\" target=\"_blank\"\u003eigns of a Failing CDI Ignition Module?\u003c\/a\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\" style=\"mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; line-height: normal;\"\u003e\u003cb\u003e\u003cspan style=\"color: #ff2a00;\"\u003ePRO TIP:\u003c\/span\u003e \u003c\/b\u003e\u003ca href=\"https:\/\/buywitchdoctors.com\/blogs\/news\/utv-atv-crank-position-sensor-symptoms-fix\" title=\"Direct link to Buywitchdoctors.com blog about How to Diagnose a Bad UTV or ATV Crank Position Sensor\" target=\"_blank\"\u003e\u003cb\u003e\u003cspan style=\"color: blue;\"\u003eHow to Diagnose a Bad UTV or ATV Crank Position Sensor\u003c\/span\u003e\u003c\/b\u003e\u003c\/a\u003e\u003cb\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\" style=\"mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; line-height: normal;\"\u003e\u003cb\u003e\u003cspan style=\"color: #ff2a00;\"\u003ePRO TIP:\u003c\/span\u003e\u003c\/b\u003e \u003cstrong\u003eLearn more about \u003ca href=\"https:\/\/buywitchdoctors.com\/blogs\/news\/utv-atv-sensor-buyer-s-guide-map-o2-tps-more\" rel=\"noopener\" title=\"Direct link to buywitchdoctors.com blog about UTV \u0026amp; ATV Sensor Buyer’s Guide: Map, O2, TPS \u0026amp; More\" target=\"_blank\"\u003e\u003cspan style=\"color: blue;\"\u003eUTV \u0026amp; ATV Sensor Buyer’s Guide: Map, O2, TPS \u0026amp; More.\u003c\/span\u003e\u003c\/a\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\" style=\"mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; line-height: normal;\"\u003e\u003cb\u003e\u003cspan style=\"mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin; color: #ff2a00; background: white;\"\u003ePRO TIP:\u003c\/span\u003e\u003c\/b\u003e\u003cb\u003e\u003cspan style=\"mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin; color: #1d2228; background: white;\"\u003e \u003ca href=\"https:\/\/buywitchdoctors.com\/blogs\/news\/how-to-test-replace-utv-atv-pickup-coil\" target=\"_blank\"\u003e\u003cspan style=\"color: blue;\"\u003eHow to Test, Diagnose, and Replace a UTV or ATV Pick-Up Coil\u003c\/span\u003e\u003c\/a\u003e\u003c\/span\u003e\u003c\/b\u003e\u003cspan style=\"mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cbr\u003e\u003cstrong\u003eUpgrade Your Ride's Engine Management \u0026amp; Ignition System Performance Today\u003c\/strong\u003e\u003cbr\u003eA factory-fit ECM keeps fuel, spark, and timing working together for easy starts and smooth, dependable power on every ride. Complete your repair with a matching ignition coil, CDI ignition, crankshaft position sensor, and throttle position sensor so your whole engine management system stays accurate and trail-ready. Order your genuine Yamaha replacement components today from \u003ca href=\"https:\/\/buywitchdoctors.com\/collections\/find-all-yamaha-off-road-utv-atv-parts?Shop-By\/OEM\" title=\"Direct Link to the Collection of All Yamaha OEM ATV \u0026amp; UTV Parts \u0026amp; Accessories Available at BuyWitchdoctors.com.\" rel=\"noopener\" target=\"_blank\"\u003ebuywitchdoctors.com\u003c\/a\u003e and experience top-tier off-road performance!\u003cbr\u003e\u003cbr\u003e\n\u003cp\u003eAre You Looking to Find Great Places \u0026amp; Adventurous Trails to Ride Your UTV, Side by Side or ATV? Check out these highly recommended places:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/northernoutdoors.com\" title=\"Direct Link to Northern Outdoors ATV\/UTV Park\" rel=\"noopener\" target=\"_blank\"\u003eNorthern Outdoors\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/www.blm.gov\/visit\/imperial-sand-dunes\" title=\"Direct Link to Imperial Sand Dunes ATV\/UTV Park\" rel=\"noopener\" target=\"_blank\"\u003eImperial Sand Dunes\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/blm.gov\/visit\/johnson-valley-ohv-area\" title=\"Direct Link to Johnson Valley ATV\/UTV Park\" rel=\"noopener\" target=\"_blank\"\u003eJohnson Valley OHV Area\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/mycountyparks.com\" title=\"Direct Link to Gypsum City ATV\/UTV Park\" rel=\"noopener\" target=\"_blank\"\u003eGypsum City OHV Park\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/leatherwoodoffroad.com\" title=\"Direct Link to Leatherwood ATV\/UTV Park\" rel=\"noopener\" target=\"_blank\"\u003eLeatherwood Off-Road Park\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e","brand":"Off Road Express Drop Ship","offers":[{"title":"Default Title","offer_id":41655193468990,"sku":"B42-8591A-00-00","price":957.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0069\/2502\/5349\/files\/Yamaha_OEM-Part-Number_B42-8591A-00-00_aec28bdb-cd9c-4f52-afaa-0d3303a03462.png?v=1772561335","url":"https:\/\/buywitchdoctors.com\/products\/engine-control-unit-by-yamaha-b42-8591a-00-00","provider":"Witchdoctors","version":"1.0","type":"link"}