A Plug-and-Play Module for Disabling AFM / DFM for GM Vehicles

If you’ve got a newer Chevy pickup or GMC Sierra, chances are good that you’ve experienced it before: sudden shudder that feels almost like a down shift as your truck switches from full V8 mode down to only utilizing 4 cylinders. This feature, known as AFM for GM trucks, was designed to reach EPA fuel economy standards, but the implementation has been clunky at best and damaging to your engine at the worst. So one of the first aftermarket accessories many Chevy and GM truck owners need these days is a disabler. While there are tuners on the market that can effectively switch off these features, if you just want a simple plug-and-play solution to turn off AFM, Range Technology has a great product that is easy to use and incredibly affordable. And they actually offer a number of different versions of this product, each designed to achieve a different goal. While we are looking at the Range AFM disabler, Range Technology has a number of great plug and play options including the Start/Stop Disabler option as well as the fuel economy mod for GM, the AFM+. Let’s dive into the popular AFM Delete Programmer.

Quick Warning: According to the manufacturer, at this time the Range AFM / DFM Disabler does NOT work with 2019+ 6.2 10-speed applications. Sorry for any confusion this may cause.

Bullet Point Breakdown of the Range Technology AFM / DFM Disabler Module

No time to read this whole article? Just want the quick and dirty dets? “Too long; didn’t read” your fav acronym? Don’t worry. We hear ya. Here’s our Midwest Aftermarket Bullet Point Breakdown of the Range Technology AFM / DFM Disabler:

• All these devices are plug and play ready
• Installs a five year old could do: just plug them into your OBD2 port and you’re done!
• Disables Active Fuel Management on GM vehicles from 2005+
• Disables Dynamic Fuel Management on GM 5.3L vehicles from 2019+
• This product does NOT currently work with 2019+ 6.2L 10 speed applications from GM
• Eliminates studder or hesitation associated with AFM / DFM activation
• Prevents exhaust buzzing sound associated with AFM / DFM vehicles
• Maintains your engine in V8 mode now matter your speed
• Does not void warranty
• To return back to AFM / DFM active for emissions testing, just pull out the module
• Stops disproportionate wear and tear on your engine valves
• Does NOT flash or reprogram your vehicle’s onboard computer or ECU
• Unplug it and it leaves no trace or hint that it was ever there
• The simplest way to disable AFM / DFM on your truck

Disabling or Managing Your Cylinders

Let’s start with a story, in case this is all news to you. The EPA (read: Obama) set up new standards for fuel economy across the board for vehicle manufacturers back in the early two thousands (okay, so that was before Obama’s time, but still!). All the major vehicle manufacturers started to scramble to figure out a solution.

The issue wasn’t that the MPG standards were going to be impossible to hit. For smaller cars and even trucks it shouldn’t be that big of a deal. But with your muscle cars and mid-sized trucks, hitting those marks and still getting the power the customer’s wanted out of them was going to be an issue.

Ford opted for turbocharging smaller engines to increase fuel economy, and so far so good.

Chevy / GM and Dodge went a different route, and truck owners everywhere had to deal with it.

Instead of making major modifications to hardware, both Chrystler and General Motors decided to use modify the code from your engine computer to disable half the cylinders when the vehicle hit a steady cruising speed.

In other words, AFM or DFM / MDS respectively disable four of your eight cylinders in a V8 engine when you get to like 30 / 35 mph.

While this isn’t the end of the world, there were some--let’s call ‘em--growing pains.

The initial releases sometimes had some bugs. Engines were damaged. Repairs and updates were made. The newest version of these systems shifts pretty well, most of the time. But even now that they have most of the bugs worked out, there’s still one gapping ironic issue:

In most cases, disabling half your cylinders didn’t actually lead to massive gains in fuel economy.

So yeah, there’s that. Furthermore, if the system itself is pretty useless or gives very small gains in MPG, then shouldn’t the end user, the truck owner, have the right to disable the system? It’s one thing if you bought your truck to be your daily driver / commuter vehicle. Then fuel economy is probably the most important factor for you. But let’s get this straight: most of us bought our trucks to haul stuff, to tow, to do jobs, to move people’s stuff from one place to another. In other words, fuel economy wasn’t on the top of our list when we bought our pickups.

And many truck owners found the straight shudder or shift from 8 cylinders (or 6) down to 4 cylinders (or 3) to be clunky and annoying.

Some models have even experienced disproportionate wear and tear on the always active cylinders compared to those that are deactivated sometimes.

At the end of the day, the truck community desperately wanted (and deserved) a choice here. Range Technology answered with their AFM / DFM Disabler and MDS Manager Modules.

Range had found a method of disabling these faulty and annoying systems without actually having to modify your engine computer. And that’s really just the tip of the iceberg.

Running on All Cylinders

The initial pros of these great products from Range Technology are obvious. With all your cylinders firing on your truck engine like they were initially intended to do, you have the power that your truck was designed to run on at all times. You’re never only utilizing half your cylinders.

Just imagine for a second what your life would be like if this happened to you. You're running a mile long race. You jump off the line and start getting up to speed. And right as you reach the speed that you are going to try to maintain, half your lungs shut down. Your heart starts working at half capacity. But you still need to pump just as much oxygenated blood to your muscles as before. Your body still weighs the same amount. And while you no longer have to accelerate, you still have to maintain that current velocity.

It sounds horrible. Hell, it sounds like a mild heart attack with a collapsed lung thrown in for good measure.

I can’t even imagine the stress this would put on my body, let alone my vehicle. My body in many ways is designed to self regulate and grow and heal minor injuries. My truck on the other hand can only do what it is designed to do. And the initial design, no matter what anyone tells you, involved all of the cylinders firing, not half of them.

It is certainly true that over time, once many of us were forced to spend years as guinea pigs for this new system, both MDS and AFM / DFM have improved some. But nevertheless, these systems both put added stress on your engine.

With Dodge, the MDS valve lifters have been known to go out or cause problems overtime. The repairs to this part of the vehicle are expensive and again they aren’t actually saving you much on fuel cost, so why take the risk?

Likewise, faulty AFM / DFM components are known to go out or even cause engine damage in extreme cases. Why should we be forced to take these risks and only use half the power our engines were designed to give? If we’d wanted a four cylinder vehicle, we would have bought one. Heck, my commuter car is a 4 banger. And I got it for the fuel economy. But my truck--I got my Silverado for the horsepower, towing, and hauling. Not once did fuel economy come into my equation.

Don’t get me wrong, we understand that these EPA standards were set to try to help with pollution levels. But at the end of the day, these two systems--AFM / DFM and MDS--don’t actually accomplish what they claim to.

Perhaps in the lab or on paper, these ideas work great. I can see the logic of it to a certain extent. And while you need less fuel to crank when you’re only using 4 cylinders, the mass of the vehicle remains the same. So it’s like having the same weight of your truck, with the same weight of your big engine, only you’re only using a 4 cylinder to move it.

It makes sense when you think about it that truck owners aren’t seeing big gains in fuel economy.

So save yourself the headache of a possible malfunction or wear and tear from these disabling systems, and get yourself a Range AFM / DFM Disabler for your Sierra or Silverado or a Range MDS Manager for your Dodge Ram.

DFM (the new and “improved” AFM)

And, yes, “improved” is in quotes because I’m not buying it!

DFM, or Dynamic Fuel Management, is GM’s next attempt to reach EPA standards without making major modifications to their classic small block V8. And I get it and I don’t. See above.

The major update here is that instead of just disabling half your cylinders at certain points, DFM will disable up to 7 of them.

Go ahead and cheer out loud. I dare you.

So basically this is an albeit smoother version of cylinder deactivation, so there should be less stutter, and yet all the other issues we’ve had with AFM, such as increased wear and tear on some cylinders over others, still lingers with this updated version.

So basically, DFM is better than AFM for fuel economy, but not by much, and definitely not better if you actually want to use all your cylinders and drive your truck like it’s a truck, not a Prius.

Sigh.

While the Range Technologies AFM / DFM Disabler will work on the 5.3L models from 2019 and 2020 and hopefully going forward until future notice, we do want to make sure those of you who are rocking a 6.2L 10 speed from 2019+ that your truck is not currently compatible with this product. We’re hoping for an update from Range soon about this, or at the very least a separate product that can disable DFM on the 6.2L 2019+ GM trucks, but as of this writing, late November 2020, no such product is available. Our humble apologies to all the 6.2L GM owners out there. We were disappointed too.

A Quick Video Guide from Range

Our Promise of Exceptional Service and the Lowest Prices on the Interwebs

When you’re ready to order your AFM / DFM Disabler from Range Technology, we hope you’ll get yours from us here at Midwest Aftermarket. We only promote products we believe in and sell them at the lowest prices, shipping quickly to you for free if you’re in the lower 48 states. We have an excellent return policy and strive to get you the right product in perfect condition the first time.

What are you waiting for? Give us a call or place an order directly through our website. We’ll get your product out to you ASAP so you can enjoy your vehicle and make it your own. If you have a vision of what your truck or Jeep could be, let us help you achieve that image, that goal. We put aftermarket right at the tip of your fingers on your smartphone, web browser, and even via various apps, making ordering the parts you need super easy. Let us help make your aftermarket dream possible. Let us help you build your dream machine. We want you to drive the truck or Jeep of your dreams right now. So when you get it installed and love it, make sure you share us some pics on social media so we can live vicariously through you. Because we too are aftermarket enthusiasts, truck and Jeep owners, who love and own many of the products we sell. In other words, we don’t just work aftermarket--we are aftermarket.

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Q: How long do I leave it in for?

A: It has to stay plugged in. 

Q: Is this updated to the latest firmware?

A: Yes, all units shipped from Midwest Aftermarket are updated. 

Q: Is the light really bright at night?

A: No, you can hardly see it and when you turn the vehicle off the light turns off aswell.

Q: What does this device do?

A: This device disables the active fuel management system in the V8 GM vehicles and keeps the engine from shifting back and forth from V4 to V8.

Q: What if I don't like the product?

A: Midwest Aftermarket will take the return back within the first 30 days and even pay return shipping!