As GM Authority recently covered, General Motors is currently building units of the 2021 Chevy Silverado 1500 and 2021 GMC Sierra 1500 light-duty pickup trucks without Active Fuel Management (AFM) or Dynamic Fuel Management (DFM). Previously equipped as standard, GM has now elected to build units from both lines without the fuel-saving tech as a result of the ongoing global microchip shortage. Now, GM Authority is taking a closer look at which models will keep AFM / DFM, and which models will not.
Before we launch into this, it’s worth providing a little background info on what Active Fuel Management and Dynamic Fuel Management actually are. Active Fuel Management is a GM technology that deactivates half of an engine’s cylinders under light driving conditions, enhancing fuel economy in the process. This technology was previously equipped on all Chevy Silverado and GMC Sierra pickups outfitted with the naturally aspirated 5.3L V8 L82 gasoline engine.
Meanwhile, Dynamic Fuel Management is similar to Active Fuel Management in that it also deactivates cylinders for greater fuel economy. However, compared to AFM, DFM is more advanced, and features 17 different cylinder activation patterns for even-greater optimization of power delivery and efficiency.
Now, due to the ongoing microchip shortage, only certain models in the Chevy Silverado and GMC Sierra lineup will continue to offer AFM / DFM.
For the Chevy Silverado, Custom Crew Cab 4WD models with the Custom Max Trailering Package (RPO code BD1) will keep AFM with the L82 V8 engine, while all other Custom trim levels and configurations will lose the tech. Additionally, the LT Trail Boss trim will keep DFM with the L84 V8, as will High Country 4WD models (High Country 2WD models do not).
| Trim Level | Engine | Transmission | Fuel Management |
|---|---|---|---|
| Work Truck | 5.3L V8 L82 | 6-speed automatic | No AFM |
| Custom Crew Cab 4WD (with BD1 Custom Max Trailering Package) | 5.3L V8 L82 | 6-speed automatic | AFM |
| Custom (all other variants) | 5.3L V8 L82 | 6-speed automatic | No AFM |
| Custom Trail Boss | 5.3L V8 L82 | 6-speed automatic | No AFM |
| LT | 5.3L V8 L84 | 8-speed automatic | No DFM |
| RST | 5.3L V8 L84 | 8-speed automatic | No DFM |
| LT Trail Boss | 5.3L V8 L84 | 10-speed automatic | DFM |
| High Country 2WD | 5.3L V8 L84 | 8-speed automatic | No DFM |
| High Country 4WD | 5.3L V8 L84 | 10-speed automatic | DFM |
With regard to the GMC Sierra, the SLE 4WD, Elevation 4WD, SLT 4WD, AT4, and Denali 4WD models all retain DFM (basically, all models that feature the 10-speed automatic transmission).
| Trim Level | Engine | Transmission | Fuel Management |
|---|---|---|---|
| Sierra | 5.3L V8 L82 | 6-speed automatic | No AFM |
| SLE 2WD | 5.3L V8 L84 | 8-speed automatic | No DFM |
| SLE 4WD | 5.3L V8 L84 | 8-speed automatic | No DFM |
| SLE 4WD | 5.3L V8 L84 | 10-speed automatic | DFM |
| Elevation 2WD | 5.3L V8 L84 | 8-speed automatic | No DFM |
| Elevation 4WD | 5.3L V8 L84 | 8-speed automatic | No DFM |
| Elevation 4WD | 5.3L V8 L84 | 10-speed automatic | DFM |
| SLT 2WD | 5.3L V8 L84 | 8-speed automatic | No DFM |
| SLT 4WD | 5.3L V8 L84 | 8-speed automatic | No DFM |
| SLT 4WD (with PDT SLT Premium Plus Package) | 5.3L V8 L84 | 10-speed automatic | DFM |
| SLT 4WD (with PDW Texas Edition SLT Premium Plus Package) | 5.3L V8 L84 | 10-speed automatic | DFM |
| AT4 | 5.3L V8 L84 | 10-speed automatic | DFM |
| Denali 2WD | 5.3L V8 L84 | 8-speed automatic | No DFM |
| Denali 4WD | 5.3L V8 L84 | 10-speed automatic | DFM |
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Comments
These are off cycle credit features that the EPA awards specific credits on as they can not be measure easily in testing.
I expect the models of greatest need will retain it while lesser models that can live more easily with out the credit
You may want to dig a little deeper on this as there is a host of off cycle credits out there that range from AFM to even some paints that reflect sun heat. It is a real scam the EPA has going but it works well for the mfgs.
The negative is we get stuck with AFM, engine stop etc as customers adding to the price of vehicles.
There’s no credit for cylinder deactivation. You’re confusing it with auto start-stop.
I have heard that all other hardware is in place even without the chip present. Does that include the valve train system that leaks oil into the cylinders, that is the problem in the first place. Can the truck be built now with a standard valve system? This will make it more appealing to many of us who expect our motors to last more than 100,000 miles. I will not buy a vehicle with this problematic hardware on it. I have first hand experience with this. It is not worth the extra 1-2 mpg.
The AFM is a root cause for bent piston rods in the GM engine. Why GM refuses to fix the problem will only result in a class action suit. Too many engines have been damaged because of it. Wise owners deactivate the AFM or buy a module to deactivate it to save their engines. Don’t believe me, search problems with AFM in GM engines 6.2 and 5.3. 2014-2018
I saw a Ferrari with stop start. The Horror!
WOW!!!!!!!! It would be great, if the “Chip shortage” was permanent! Anyone who has had problems with these “Full Saving” ideas, knows they are crazy stupid. They go haywire, and GM says you used the wrong oil. That’s why there is a class action law suit. Both of these set ups, are in need of a very hard revamp. Shutting 4 cylinders down, or shutting off the engine at a stop, is not only insane, it’s very dangerous. Get rid of both of these for ever!!!!!!!!!!!
You are in the minority there pal. This stuff is in no way dangerous. Let me guess, you are the same type of person that says the stock halogen headlights are dangerous or an upshift early is dangerous when pulling out of the drive in to fast oncoming traffic? Either way, your rant is laughable. The amount of people that have had problems are very few and far between out of the millions that have been built. It stinks you had problems, but there will be rogue issues as it is a mechanical unit made by machines and people, stuff happens. Haven’t heard anything about a class action lawsuit and AFM engine failures, only oil consumption which has been thrown out numerous times. Pretty simple to check your oil and use the right viscosity, they call that out in the manual for a reason… I would much rather have them on there than not have these engines, they have to in order to keep them around. If you don’t like it don’t buy it, there are numerous smaller turbo engines of your choosing…
Commonsense, I agree! I’ve had 3 different GM trucks with the 5.3 AFM, and have put a combined 250K + miles on them, without any issues. The same is true for the 3.6 AFM V6 in my wife’s 2017 XT5. Additionally, everyone I know who has either a 5.3 or 6.2 AFM/DFM, have been happy with them.
I’ve never experienced any excessive oil use, and the transition from V8 to V4 mode is always seamless. Additionally, the 5.3 in my 2016 GMC SLT crew cab, regularly gets 22-24 mpg cruising at 75 mph, which is far better than friends ever see with thier V6 turbo F-150’s, or Hemi Ram’s.
I have a 2021 5.3L Sierra Denali on order, that’s scheduled to be built this week. I for one was very happy yesterday, when my dealer told me that 10 speed, 4×4 Denali’s would continue to get the the DFM version of the 5.3 V8.
My 6.2L 2015 Silverado High Country suffered a bent piston rod, the owner of the shop had the same thing happen to his, my hunting friends son had the same happen to his. All around 70,000 miles. $6800 repair bill. It’s not if it’s when the next one happens. Shutting down from V8 to V4 causes oil carbon and other crud to build up in the non functioning valve thus eventually blocking the piston rod. IT’S HAPPENING FREQUENTLY
Yep!! Cylinder Deactivation causes excess wear to the engine. That’s basic common sense that most people don’t have.
At least you see it and know the problems associated with DOD.
the problem is the oil pressure. use of incorrect oil or following MFR recommended oil changes degrades the viscosity and then the lifter does not fully pump back up. the result is lift ticking which is really the lifter hitting the cam and causing damage and metal in the engine, this make it worse because that metal clogs the oil passage even more. the bent rods are probably due to excessive carbon on the valves from direct injection causing the valves to stick thus hitting the piston.
Pete, one thing that is proven is that DFM will save your cylinder rings. Rebuilding AFM engines show normal wear on the always on cylinders, much less on the off cylinders. With DFM, you will significantly reduce ring wear and extend the engine life of your engine, which is important on long haul vehicles. I do own a first gen 5.3 AFM and have no oil consumption problems, but I’ve always used full synthetic. My first car in high school was a Pontiac sun fire 4 banger. I put in cheap oil, blew out the rings after 40,000 miles. Swapped in a junkyard unit, ran full synthetic from a name brand, put 220,000 on that motor. Oil quality really makes a difference, and it’s not 5w30 vs 10w40 or strait 20 weight, it’s mineral vs synthetic, oil brand, and even refinery of origin. You cheap out with some junk off a gas station store and tow with it for 10,000 miles, your going to put 50,000 miles of wear on your engine.
Before you get too carried away these Rube Goldberg ideas are what is keeping higher power and many larger engines viable for sale. With out you may lose HP and v8 engines.
Like em or not these off cycle credits keep the stuff we like viable.
So all the 10 speeds keep the DFM, probably due to the extra cost
LTZ trim?
I would guess no, but the LTZ trim is not listed.
I believe the 6.2 is DFM right? Is it staying? That is probably the one that will have the biggest mileage drop without it.
Yes, I have a 6.2 Trail boss LT on order. Didn’t see it mentioned either way, unless I missed it.
I have a 2021 Custom Trail Boss that I bought in February. Does this include my truck as well? Or is it only the listed trucks built after a certain date.
Should the 2021 Sierra 3500HD SLT 4WD with premium packages have AFM/DFM? Just took delivery, and it is not there to my surprise.
My brand new 2021 Chevy Silverado 1500 with the 5.3 is in the shop now at 3000 miles with a bent pushrod. I’ve only had it two months. Multiple engine warning lights. Emergency brake, ESC, number two cylinder missing, emission system, traction control, to top it off the dealer has been rude to me. No loaner vehicle. This is at Power Chevrolet Sublimity, Oregon.
My 2021 Silverado 1500 is in the shop with lifter problems (thats what they told me). It has all of 6200 miles. Beginning to regret the purchase. Also no loaner.
It is not just the carbon build-up,,,you also have extreme heat differentials between firing and non-firing cylinders.
And dont get me started about computers interrupting the operation of some exhuast/intake valves while allowing others to function. What could go wrong with that 🙂
I just got a GMC 2021 sierra elevation with 5.3 I couldn’t find anything in the manual except 6.2 info would any of you know where I could find that info on the truck including what size Trany I want to know if it has the DFM
I have a 2021 GMC Sierra SLT 1500 6.2L w/about 18,500 miles – 18,500!! Just got it out of the shop for failed lifter which caused a bent rod. Fortunately for me it is still under warranty, but this is ominous. Can’t figure out or determine which I have, if any at all – either AFM or DFM. Anyone know the absolute way to determine?
Not because of Chip shorted faulty engineering LOL GM waste of $40,000 for a new pickup just for it to break down on me every year
How could anyone be cheerleading for this ridiculous BS technology that is complete bureaucratic nonsense. The Earth does not need people to save it. If the Earth gets tired of humans it will drown you or melt your @ss with lava and recycle you to cleanse itself.
You are exactly right – only idiots are still supporting this technology. Its obvious that there is a high failure rate in (2021 at least) 6.2l engines with DFM (all of them have DFM?). I wonder if the cheerleaders above (from 2-3 years ago) are still singing praises. The comment about ring wear I found particularly cute, and I agree – if my engine is down repeatedly due to bent push rods and damaged valves, then the piston ring wear would definitely be decreased – lol.
I realize however, that at the end of the day it was my decision to purchase a GM truck – but for the life of me I can’t find where I could have known about the DFM.
28000, and awaiting my next breakdown.