{"product_id":"afm-dfm-vcm-disabler-chevrolet-trailblazer-2005-2009-afm-dfm-disabler","title":"Chevrolet Trailblazer 2005-2009 5.3L V8 AFM\/DFM Disabler","description":"\u003cp\u003eThis AFM\/DFM disabler plugs into the OBD-II port of the 2005–2009 Chevrolet Trailblazer. Its job is to keep the engine running on all cylinders instead of dropping into the reduced-cylinder mode that GM's Active Fuel Management uses at light load. No tools, no wiring and no reflash of the engine computer. Unplug it and AFM works again as it did from the factory.\u003c\/p\u003e\u003ch2\u003eFitment by year and engine\u003c\/h2\u003e\u003cp\u003eEach row below is listed as a 100% fitment match:\u003c\/p\u003e\u003cul\u003e\u003cli\u003e2005–2009 Chevrolet Trailblazer: 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\u003eAn engine code that is not listed here does not automatically rule the vehicle out, but send us the VIN first so we can check.\u003c\/p\u003e\u003ch2\u003eThe factory system in brief\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\u003eAfter installation\u003c\/h2\u003e\u003cp\u003eThe difference shows up in light-load driving: steady highway speeds, gentle acceleration and coasting down small grades. Those are the moments when AFM used to drop cylinders. With the module in, engine behavior there should feel the same as under heavier throttle. Full-throttle performance does not change, because AFM was never active at full throttle anyway.\u003c\/p\u003e\u003ch2\u003eIf the engine already has symptoms\u003c\/h2\u003e\u003cp\u003eScan for stored codes before you plug it in. Misfire codes on the deactivation cylinders, an AFM solenoid circuit code, or a lifter noise are signs of an existing problem that should be repaired first. The module is meant for a healthy engine where you simply do not want cylinder deactivation.\u003c\/p\u003e\u003ch2\u003eKeep up with oil changes\u003c\/h2\u003e\u003cp\u003eAFM lifters and the solenoids that control them run on engine oil pressure. Keeping the oil at the right level, using the grade GM specifies on the oil filler cap or in the owner's manual, and changing it on schedule matters whether or not AFM is active. The module changes when cylinders deactivate; it does not change the oiling system.\u003c\/p\u003e\u003ch2\u003eWhy people turn AFM off\u003c\/h2\u003e\u003cp\u003eThe usual complaints are a drone or shudder in reduced-cylinder mode, a slight hesitation when the engine switches back, and a general wish to keep the valvetrain doing the same thing all the time. With the module installed, the engine stays in full-cylinder mode, so those transitions stop. Expect light-load fuel economy to be closer to an engine without AFM.\u003c\/p\u003e\u003ch2\u003eLiving with it\u003c\/h2\u003e\u003cp\u003eBecause it occupies the OBD-II port, unplug the module before connecting a scan tool, an insurance logger or an emissions-test probe, then plug it back in afterwards. Make sure it sits clear of your left knee and the pedals, and that the housing is fully seated in the port.\u003c\/p\u003e\u003ch2\u003eOther ways owners disable AFM\u003c\/h2\u003e\u003cp\u003eThere are three common ways to stop cylinder deactivation on GM engines: a plug-in module like this one, a custom tune that turns AFM off in the engine computer, or a mechanical delete that replaces the AFM lifters and related hardware and then needs a tune to match. The module is the only one of the three that needs no tools and no engine-computer changes, and it is the only one you can undo by unplugging it. It does not replace failed lifters; if hardware is already damaged, the repair comes first.\u003c\/p\u003e\u003ch2\u003eCheck before ordering\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eYour model year, model and engine match a row in the table (2005–2009 Chevrolet Trailblazer).\u003c\/li\u003e\n\u003cli\u003eFind your engine code. On GM vehicles before the 2018 model year, the Service Parts Identification label (usually inside the glovebox on these trucks and SUVs) lists the three-character RPO codes, and the engine code starts with L. From 2018, GM moved that data into a QR code on the certification label on the driver-side door pillar. The 8th character of the VIN also identifies the engine.\u003c\/li\u003e\n\u003cli\u003eThe engine runs cleanly with no stored misfire or AFM codes.\u003c\/li\u003e\n\u003cli\u003eEngine swaps, custom tunes and replaced ECUs need a fitment check from support before ordering.\u003c\/li\u003e\n\u003cli\u003eQuestions: support@automotivebypass.com with your VIN.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eFitment table with engine codes\u003c\/h2\u003e\u003cp\u003eEach model year from the fitment data, with the AFM engine codes GM used for that year and displacement:\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\u003eChevrolet\u003c\/td\u003e\n\u003ctd\u003eTrailblazer\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\u003eChevrolet\u003c\/td\u003e\n\u003ctd\u003eTrailblazer\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\u003eChevrolet\u003c\/td\u003e\n\u003ctd\u003eTrailblazer\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\u003eChevrolet\u003c\/td\u003e\n\u003ctd\u003eTrailblazer\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\u003eChevrolet\u003c\/td\u003e\n\u003ctd\u003eTrailblazer\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\u003eLH6 background\u003c\/h2\u003e\u003cp\u003eBesides the TrailBlazer and Envoy, the LH6 went into the Buick Rainier, Saab 9-7X and Isuzu Ascender, and into some 2007–2009 Silverado 1500 and Sierra 1500 pickups. It replaced the Gen III LM4 for 2005 and was the first Generation IV truck V8 to go into production.\u003c\/p\u003e\u003ch2\u003ePlatform and engine notes\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\u003eWhy oil matters on these engines\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\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\u003eTroubleshooting\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eWarning light appears:\u003c\/strong\u003e Remove the module, scan for codes and email support with the code and VIN.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eMode changes still felt:\u003c\/strong\u003e Re-seat the module and confirm your engine code is on the AFM list for this listing.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eShop cannot reach the diagnostic port:\u003c\/strong\u003e Unplug the module for the visit and refit it afterwards.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eLifter noise or misfire codes:\u003c\/strong\u003e These point to existing engine faults that need diagnosis and repair.\u003c\/p\u003e\u003ch2\u003eA short history of GM cylinder deactivation\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\u003eTerms used on this page\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eDoD:\u003c\/strong\u003e Displacement on Demand, the original name for AFM.\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\u003eAFM:\u003c\/strong\u003e Active Fuel Management, GM's cylinder deactivation system on the engines covered here.\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\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\u003eVIN 8th digit:\u003c\/strong\u003e The VIN character that identifies the engine.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eRPO code:\u003c\/strong\u003e GM's three-character option code; engine codes begin with L.\u003c\/p\u003e\u003ch2\u003eEngine code notes\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\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\u003eFAQ\u003c\/h2\u003e\u003ch3\u003eWhich Chevrolet Trailblazer years and engines does it fit?\u003c\/h3\u003e\u003cp\u003eThe fitment table lists Chevrolet Trailblazer 2005–2009 with 5.3L V8. Match your exact year and engine to a row before ordering.\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\u003eHow do I tell which engine my Chevrolet Trailblazer 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\u003eDoes it plug into the OBD-II port on the Chevrolet Trailblazer?\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\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\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\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\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\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\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 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\u003ch2\u003eShipping and support\u003c\/h2\u003e\u003cp\u003eStandard shipping inside the lower 48 states costs nothing; allow 1–2 business days of handling plus 3–4 in transit. Returns need approval first and must be requested within 45 days. Approved returns are subject to a 20% restocking fee, with return shipping paid by the customer. A 3-year limited warranty applies. Email support@automotivebypass.com (Mon–Fri, 9–5 PST) with your VIN if you want a fitment check.\u003c\/p\u003e","brand":"Automotivebypass","offers":[{"title":"Default Title","offer_id":56493782729076,"sku":"RC-AFM-DFM-01-08","price":79.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1030\/8439\/2820\/files\/RC-AFM-DFM-01-08-1.jpg?v=1793172201","url":"https:\/\/automotivebypass.com\/products\/afm-dfm-vcm-disabler-chevrolet-trailblazer-2005-2009-afm-dfm-disabler","provider":"Automotivebypass","version":"1.0","type":"link"}