{"product_id":"afm-dfm-vcm-disabler-gmc-envoy-2005-2009-afm-dfm-disabler","title":"GMC Envoy 2005-2009 5.3L V8 AFM\/DFM Disabler","description":"\u003cp\u003eFits the 2005–2009 GMC Envoy. The module connects at the OBD-II port and keeps GM's cylinder deactivation from switching on, which means steady all-cylinder operation instead of repeated changes between full and partial mode. There is no tune involved and nothing inside the engine is changed. Pull it out of the port and the factory strategy returns.\u003c\/p\u003e\u003ch2\u003eWhat it fits\u003c\/h2\u003e\u003cp\u003eListed applications, each a 100% fitment match:\u003c\/p\u003e\u003cul\u003e\u003cli\u003e2005–2009 GMC Envoy: 5.3L V8\u003c\/li\u003e\u003c\/ul\u003e\u003cp\u003eAFM-equipped engine codes that GM used in these years and sizes:\u003c\/p\u003e\u003cul\u003e\u003cli\u003eLH6 (5.3L, 2005–2009, VIN 8th digit \"M\")\u003c\/li\u003e\u003c\/ul\u003e\u003cp\u003eIf your engine code is not in this list, email the VIN to support before ordering so we can confirm the application.\u003c\/p\u003e\u003ch2\u003eHow Active Fuel Management operates\u003c\/h2\u003e\u003cp\u003eGM's Active Fuel Management turns a V8 into a V4 at light load by deactivating cylinders 1, 7, 6 and 4. Solenoids route oil pressure to the lifters on those cylinders, which collapse and stop opening the valves. Fuel to those cylinders is cut at the same time. Press the throttle harder and the system brings all eight back.\u003c\/p\u003e\u003ch2\u003eScan tools and inspections\u003c\/h2\u003e\u003cp\u003eLeave it in the port for everyday driving. When the vehicle goes in for service or an emissions check, remove it so the shop has normal access to the diagnostic connector, then reinstall it.\u003c\/p\u003e\u003ch2\u003eMaintenance still matters\u003c\/h2\u003e\u003cp\u003eDisabling cylinder deactivation does not replace normal maintenance. Use the oil grade and change interval GM lists for your engine, watch the oil level between changes, and repair leaks promptly. The valvetrain on these engines depends on clean oil at proper pressure in every mode.\u003c\/p\u003e\u003ch2\u003eWhy owners disable it\u003c\/h2\u003e\u003cp\u003eOwners usually disable AFM for one of three reasons: they notice the change between modes as a vibration or exhaust drone, they want a consistent throttle response while towing or climbing grades, or they want to limit how often the deactivation lifters switch. Keeping the engine on all cylinders addresses all three. The tradeoff is that you give up whatever fuel saving AFM was providing in light cruising.\u003c\/p\u003e\u003ch2\u003eWhat changes when you drive\u003c\/h2\u003e\u003cp\u003eExpect steadier behavior at part throttle and no change at wide-open throttle. Towing and hill climbing were already mostly done on all cylinders, so the biggest change is during relaxed cruising. Average fuel economy may drop slightly depending on how much of your driving is light-load highway time.\u003c\/p\u003e\u003ch2\u003eDiagnose existing problems first\u003c\/h2\u003e\u003cp\u003eThis module prevents mode switching. It does not repair anything. If the engine already has a ticking lifter, misfire codes, low oil pressure or high oil consumption, have it diagnosed before relying on the module. Those symptoms need a mechanical repair, and keeping AFM off will not reverse damage that has already happened.\u003c\/p\u003e\u003ch2\u003eOther ways owners disable AFM\u003c\/h2\u003e\u003cp\u003eOwners who want AFM gone for good sometimes go the mechanical route: non-AFM lifters, a matching camshaft and a retune. That is a large job and it is permanent. A tuner can also disable AFM in the engine computer. The plug-in module sits at the other end of the scale: no parts replaced, no software rewritten, and back to factory with one pull. It is meant for engines that run well and simply should not switch modes.\u003c\/p\u003e\u003ch2\u003eHow to confirm your engine code\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eYour model year, model and engine match a row in the table (2005–2009 GMC Envoy).\u003c\/li\u003e\n\u003cli\u003eThe quickest checks are the 8th digit of your VIN, which identifies the engine, and the RPO list on the Service Parts Identification label (glovebox or trunk on most pre-2018 GM models, QR code on the driver-door pillar label from 2018).\u003c\/li\u003e\n\u003cli\u003eThe engine runs cleanly with no stored misfire or AFM codes.\u003c\/li\u003e\n\u003cli\u003eIf the vehicle has an engine swap, an aftermarket tune or a replacement engine computer, contact support first.\u003c\/li\u003e\n\u003cli\u003eQuestions: support@automotivebypass.com with your VIN.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eYear-by-year fitment\u003c\/h2\u003e\u003cp\u003eOne row per year. The last column shows which AFM-equipped GM engine codes match that year and engine size:\u003c\/p\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eYear\u003c\/th\u003e\n\u003cth\u003eMake\u003c\/th\u003e\n\u003cth\u003eModel\u003c\/th\u003e\n\u003cth\u003eEngine\u003c\/th\u003e\n\u003cth\u003eAFM codes\u003c\/th\u003e\n\u003cth\u003eListing note\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e2005\u003c\/td\u003e\n\u003ctd\u003eGMC\u003c\/td\u003e\n\u003ctd\u003eEnvoy\u003c\/td\u003e\n\u003ctd\u003e5.3L V8\u003c\/td\u003e\n\u003ctd\u003eLH6\u003c\/td\u003e\n\u003ctd\u003e100% Fitment Match | OEM-Grade Quality | Plug \u0026amp; Play\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e2006\u003c\/td\u003e\n\u003ctd\u003eGMC\u003c\/td\u003e\n\u003ctd\u003eEnvoy\u003c\/td\u003e\n\u003ctd\u003e5.3L V8\u003c\/td\u003e\n\u003ctd\u003eLH6\u003c\/td\u003e\n\u003ctd\u003e100% Fitment Match | OEM-Grade Quality | Plug \u0026amp; Play\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e2007\u003c\/td\u003e\n\u003ctd\u003eGMC\u003c\/td\u003e\n\u003ctd\u003eEnvoy\u003c\/td\u003e\n\u003ctd\u003e5.3L V8\u003c\/td\u003e\n\u003ctd\u003eLH6\u003c\/td\u003e\n\u003ctd\u003e100% Fitment Match | OEM-Grade Quality | Plug \u0026amp; Play\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e2008\u003c\/td\u003e\n\u003ctd\u003eGMC\u003c\/td\u003e\n\u003ctd\u003eEnvoy\u003c\/td\u003e\n\u003ctd\u003e5.3L V8\u003c\/td\u003e\n\u003ctd\u003eLH6\u003c\/td\u003e\n\u003ctd\u003e100% Fitment Match | OEM-Grade Quality | Plug \u0026amp; Play\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e2009\u003c\/td\u003e\n\u003ctd\u003eGMC\u003c\/td\u003e\n\u003ctd\u003eEnvoy\u003c\/td\u003e\n\u003ctd\u003e5.3L V8\u003c\/td\u003e\n\u003ctd\u003eLH6\u003c\/td\u003e\n\u003ctd\u003e100% Fitment Match | OEM-Grade Quality | Plug \u0026amp; Play\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch2\u003eInstall prep checklist\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eScan the engine for stored codes and note any misfire or AFM solenoid codes.\u003c\/li\u003e\n\u003cli\u003eCheck the oil level and confirm the grade matches GM's specification for your engine.\u003c\/li\u003e\n\u003cli\u003eSwitch the ignition off before inserting the module.\u003c\/li\u003e\n\u003cli\u003eLocate the OBD-II port under the driver-side dash.\u003c\/li\u003e\n\u003cli\u003ePush the module in until it is fully seated and sits clear of your knee and the pedals.\u003c\/li\u003e\n\u003cli\u003eStart the engine and let it idle before driving.\u003c\/li\u003e\n\u003cli\u003eTake a drive at steady light throttle, where AFM used to engage, and confirm the engine stays on all cylinders.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eWhere AFM came from\u003c\/h2\u003e\u003cp\u003eGM first sold cylinder deactivation in 1981 with the Cadillac V8-6-4. The modern system was announced in 2003 as Displacement on Demand and reached production on the 2005 Chevrolet TrailBlazer EXT and GMC Envoy XL and XUV with the 5.3L V8, followed by the 5.3L LS4 in the Impala SS, Monte Carlo SS and Pontiac Grand Prix GXP. Renamed Active Fuel Management, it spread across GM's Gen IV and EcoTec3 truck engines. For the 2019 Silverado, GM introduced Dynamic Fuel Management, based on Tula Technology's Dynamic Skip Fire, which can deactivate cylinders individually.\u003c\/p\u003e\u003ch2\u003ePublished ratings for these engines\u003c\/h2\u003e\u003cp\u003ePublished output and key features of the relevant engines. Exact ratings depend on the vehicle and model year:\u003c\/p\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eRPO code\u003c\/th\u003e\n\u003cth\u003eSize\u003c\/th\u003e\n\u003cth\u003ePower\u003c\/th\u003e\n\u003cth\u003eTorque\u003c\/th\u003e\n\u003cth\u003eCompression\u003c\/th\u003e\n\u003cth\u003eNotes\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\u003ctr\u003e\n\u003ctd\u003eLH6\u003c\/td\u003e\n\u003ctd\u003e5.3L\u003c\/td\u003e\n\u003ctd\u003e300–315 hp\u003c\/td\u003e\n\u003ctd\u003e330–338 lb-ft\u003c\/td\u003e\n\u003ctd\u003e9.95:1\u003c\/td\u003e\n\u003ctd\u003ealuminum block, AFM\u003c\/td\u003e\n\u003c\/tr\u003e\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch2\u003eLH6 background\u003c\/h2\u003e\u003cp\u003eThe LH6 replaced the Gen III LM4 for the 2005 model year and was the first Gen IV truck V8 built. Other users of the same engine include the Buick Rainier, Saab 9-7X, Isuzu Ascender and some 2007–2009 Silverado 1500 and Sierra 1500 trucks.\u003c\/p\u003e\u003ch2\u003eIf something seems wrong\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eCheck-engine light after fitting:\u003c\/strong\u003e Unplug the module, read the code and contact support with the code and the VIN.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eEngine still feels like it is switching modes:\u003c\/strong\u003e Confirm the module is fully seated in the port and that the engine code is an AFM engine listed for this vehicle.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eScan tool will not connect:\u003c\/strong\u003e The module occupies the port; remove it while the tool is in use.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eTicking or misfire continues:\u003c\/strong\u003e That is a mechanical or ignition fault. The module prevents switching; it does not repair hardware.\u003c\/p\u003e\u003ch2\u003eThe engines behind the codes\u003c\/h2\u003e\u003cul\u003e\u003cli\u003e\n\u003cstrong\u003eLH6\u003c\/strong\u003e: aluminum-block 5.3L V8 used in midsize SUVs, one of the first GM engines with Displacement on Demand. VIN engine digit \"M\".\u003c\/li\u003e\u003c\/ul\u003e\u003ch2\u003eTerms used on this page\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eRPO code:\u003c\/strong\u003e GM's three-character option code; engine codes begin with L.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eOBD-II port:\u003c\/strong\u003e The standard diagnostic connector under the dash on every US vehicle since 1996.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eVIN 8th digit:\u003c\/strong\u003e The VIN character that identifies the engine.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDFM:\u003c\/strong\u003e Dynamic Fuel Management, the system on 2019-on L84 and L87 engines that can deactivate cylinders individually.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoD:\u003c\/strong\u003e Displacement on Demand, the original name for AFM.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eSPID label:\u003c\/strong\u003e Service Parts Identification label listing the RPO codes on pre-2018 GM vehicles.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eAFM:\u003c\/strong\u003e Active Fuel Management, GM's cylinder deactivation system on the engines covered here.\u003c\/p\u003e\u003ch2\u003eModel background\u003c\/h2\u003e\u003cp\u003eThe 2005 Chevrolet TrailBlazer EXT and GMC Envoy XL and XUV were the first GM vehicles sold with Displacement on Demand, using the 5.3L V8. The 5.3L LH6 in these midsize SUVs carried cylinder deactivation through the 2009 model year, when the line ended.\u003c\/p\u003e\u003ch2\u003eWhat is inside an AFM engine\u003c\/h2\u003e\u003cp\u003eInside the valley of an AFM V8 sits a solenoid assembly that feeds oil to two-stage hydraulic lifters on the cylinders that shut down. When a solenoid opens, the lifter collapses and the valve stays closed. The whole system depends on oil pressure, so oil grade, level and change intervals affect how it behaves. With the module installed, the switching no longer happens, but the lifters are still oil-fed and still need clean oil at the right pressure.\u003c\/p\u003e\u003ch2\u003eQuestions owners ask\u003c\/h2\u003e\u003ch3\u003eHow do I tell which engine my GMC Envoy has?\u003c\/h3\u003e\u003cp\u003eCheck the 8th digit of the VIN or the RPO codes on the Service Parts Identification label (QR code on the door-pillar label on 2018 and newer GM models).\u003c\/p\u003e\u003ch3\u003eWill it fix lifter noise or misfires?\u003c\/h3\u003e\u003cp\u003eNo. Those are mechanical or electrical faults that need their own diagnosis and repair.\u003c\/p\u003e\u003ch3\u003eDoes it plug into the OBD-II port on the GMC Envoy?\u003c\/h3\u003e\u003cp\u003eYes. It plugs into the OBD-II port under the dash. There is no wiring or splicing.\u003c\/p\u003e\u003ch3\u003eWhich GMC Envoy years and engines does it fit?\u003c\/h3\u003e\u003cp\u003eThe fitment table lists GMC Envoy 2005–2009 with 5.3L V8. Match your exact year and engine to a row before ordering.\u003c\/p\u003e\u003ch3\u003eDo I need to remove it for an emissions test or scan tool?\u003c\/h3\u003e\u003cp\u003eYes. It uses the diagnostic port, so unplug it while the port is needed and plug it back in afterwards.\u003c\/p\u003e\u003ch3\u003eHow much fuel does AFM save?\u003c\/h3\u003e\u003cp\u003eEPA-test estimates published for GM's system are about 5.5–7.5%, with the benefit coming from light-load cruising. Keeping all cylinders active gives up part of that, depending on how you drive.\u003c\/p\u003e\u003ch3\u003eDoes it work on 2019 and newer trucks with Dynamic Fuel Management?\u003c\/h3\u003e\u003cp\u003eOnly the vehicles and engines in this listing's fitment table are covered. DFM on the 2019-on Silverado 1500 and Sierra 1500 (5.3L L84, 6.2L L87) is a different system, so do not assume coverage outside the table.\u003c\/p\u003e\u003ch3\u003eIs a tune or ECU reflash required?\u003c\/h3\u003e\u003cp\u003eNo. The module plugs into the OBD-II port and does not rewrite the engine computer's software.\u003c\/p\u003e\u003ch3\u003eDoes it change anything when towing?\u003c\/h3\u003e\u003cp\u003eUnder heavy load, such as towing up a grade, AFM already keeps all cylinders running. The difference shows up during lighter cruising between climbs, where the engine no longer drops cylinders.\u003c\/p\u003e\u003ch3\u003eCan I go back to factory AFM?\u003c\/h3\u003e\u003cp\u003eYes. Unplug the module and the factory cylinder-deactivation strategy works again.\u003c\/p\u003e\u003ch3\u003eWill it add horsepower?\u003c\/h3\u003e\u003cp\u003eNo. It keeps all cylinders active; it does not change the engine tune.\u003c\/p\u003e\u003ch3\u003eDo I need it if my engine already has an AFM delete?\u003c\/h3\u003e\u003cp\u003eNo. An engine with the AFM hardware removed and a matching tune no longer deactivates cylinders, so the module has nothing to manage.\u003c\/p\u003e\u003ch2\u003eOrdering details\u003c\/h2\u003e\u003cp\u003eShipping is free to the contiguous US. Orders leave in 1–2 business days and usually arrive 3–4 business days later. Returns are accepted within 45 days with pre-approval; a 20% restocking fee applies and the buyer covers return shipping. The part carries a 3-year limited warranty, and support@automotivebypass.com answers Monday to Friday, 9–5 Pacific.\u003c\/p\u003e","brand":"Automotivebypass","offers":[{"title":"Default Title","offer_id":56493784924532,"sku":"RC-AFM-DFM-01-23","price":79.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1030\/8439\/2820\/files\/RC-AFM-DFM-01-23-1.jpg?v=1793172399","url":"https:\/\/automotivebypass.com\/products\/afm-dfm-vcm-disabler-gmc-envoy-2005-2009-afm-dfm-disabler","provider":"Automotivebypass","version":"1.0","type":"link"}