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Information on Vibration Analysis and Diagnostic 2014/2015 Chevrolet Silverado and GMC Sierra This seems to be a vibration campaign that has been around since January 2015. I have seen many complaints on different forums about this issue. I also have a vibration/harmonics issue that is not there all of the time but most. My issue seems to be centered around the V4 decel, and body mount configuration. This link is filled with a ton of information about various causes and repairs many of the 2014/2015 GM truck owners are experiencing. Some may be experiencing a combination of more than one issue at a time. Many more may not be experiencing any vibration at all. I do believe for those folks with the "Cadillac ride" its only a matter of time before they start experiencing vibration/harmonics issues. Its kinda nice to get this information out so that GM can streamline the repair process even further. If enough of these trucks show up for repair request for vibration they may even send out letters to further enhance quality control. http://oemdtc.com/6392/information-on-vibration-analysis-and-diagnostic-2014-2015-chevrolet-silverado-gmc-sierra/3 If link does not work copy and past in your browser.

Chevy passed out a 2019 Silverado information book to journalists during this week's media drive. I'm working on scanning the entire thing and sharing it here. There's a lot of information packed into this flip book. I thought the most interesting was the engine line up and an AFM vs DFM diagram. This is the best comparison blowout diagram I've seen so far. Here's the four pages related to the engines.

Hi everyone, I just purchased a 2016 GMC Sierra SLT Crew Cab All Terrain X a few weekends ago. The AFM (Active Fuel Management) is such a pain when switching from V4 to V8 mode at low speeds (non-highway driving) because I hate the "bogging" or "hesitating" feeling the truck gives off and the exhaust tone is UGH... I had a 2007 Avalanche and used a Range Technology device to disable it. But overtime I would have to pull the device out and plug it back in because it wouldn't activate sometimes. Been reading on this forum about the Range device for the newer Sierra's and people have been having issues with them and could mess with the computer overtime. So I won't be going that route. Another option is to get a tune like BlackBear and get it disabled or set a minimum speed of when the AFM activates. But a tune isn't an option for me right now because I want to keep my warranty as long as I can. Someday BlackBear tune will in my future! So I decided to try something. For the last couple days I have been driving in Manual mode "M" and setting it to M7 (7th gear) and driving like normal (non-highway driving). I was shifting gears up ( + ) and down ( - ) because I thought that was what you were suppose to do but I found out I can just set it to M7 and not worry about shifting, it does it for me, it just doesn't go into M8 (8th gear), which I don't need when I am going less then 50mph most days. I watched it stay in V8 mode stay the WHOLE TIME! The only time it went into V4 mode was when I shifted into M8 and then I switched back to M7 and it went back into V8 mode. So I think I found a workaround without having to void my warranty with a tune or messing up my computer with a AFM disabler device. I want to get your thoughts guys, will running in Manual "M" mode ruin the transmission in anyway? Not using M8 (8th gear) for slow speeds have long term affects with that gear? I am going to do this for another week or two and report my findings. This guy is happy when my truck isn't "bogging" or "hesitating" and have full power!!!

Does a Range AFM disabler work on a 2017 model? Their website indicates it goes up to 2016. I can't see what should be different... but I think they are overpriced to begin with, so I don't want to shell out the dollars for it if it's a paperweight. My truck is a 2017 1500 with a 5.3L & 6 speed. I only want it so that custom exhaust won't sound stupid. Had an i2 programmer for my 16 and it won't work on my 17... so I quit with the programmer, I'll stick with plug and play if it is truly that.

I have a 2016 Crew Cab Silverado 4x4 that I bought new last summer. I have noticed that recently when the active fuel management switches from 4 to 8 cylinders that there is a loud (loud enough to hear it with the windows up, A/C and radio on) squeak like noise that comes from the truck. It makes this noise every time it switches from 4 to 8, no matter what the speed. I don't remember it doing this until recently. I've googled active fuel management noise, active fuel management squeak and tons on other combinations, but haven't gotten any results. I wanted to check on here and see what you guys thought before looking like a dumb ass and taking it back to the dealership.

Hello everyone new to the community and new to Chevy trucks. I'm looking to purchase my first Silverado in the near future but after researching the current gen Silverados I keep seeing how afwul afm is in these trucks and how in extreme cases it can lead to engine failure. Can someone explain to me exactly what what the problems are that owners are seeing with this technology and my big question is, have a lot of the issues been worked out or even resolved in the 2017-2018 models? Are the problems with afm severe enough to not make it not worth getting a new Silverado? All the bad things I am reading are really pushing me away from buying one . Any and all information is welcome ! Thanks guys !

My 2012 Silver is one of the unfortunates to be cursed with AFM. It has 136k on it. It has gone through a quart of oil about every two weeks since I got it at 75k miles, plugs on 1, 4, 6 and 7 have to be changed about every 6 months (photos of #7 that got changed a few days ago because as usual, CLEARLY it was fouled and misfiring) and it DRINKS fuel. My average MPG's hovers around 10-11mpg..not to mention the horrible jolt it makes after cycling between 4 and 8 cylinders. Is there nothing I can do to, if nothing else, reduce the oil consumption?

Zane & Josh Merva Copyright, GM-Trucks.com GM’s Active Fuel Management technology is somewhat controversial. Some people love it and some people hate it. There’s been long discussions regarding how to turn the system off but almost no mention of reprogramming AFM to run more often for increased fuel savings. However today, we unbox and give our first impressions of a product designed to do just that… the Range. What does it do? Range works with the active-fuel-management system (or AFM for short) in your GM truck or SUV. The device will work on nearly all GM vehicles with AFM technology. That includes engines in the Chevy Silverado, GMC Sierra, the Cadillac Escalade, as well as the Yukon, Suburban, Avalance, and Tahoe. The Range attaches to your OBD-II diagnostic port. Through the port, it temporarily modifies the software that runs the active-fuel-management system in your engine. Without any permanent modification or software flashing, the device allows your AFM engine to run in V4 mode more often. When plugged in, the system forces four-cylinder operation through a wider range of load. When unplugged, the engine reverts to stock and nothing is left changed. Range Technology describes it best: The theory is by forcing your engine to run in V4 mode more often, you can get better fuel economy in your truck. Range says an average owner can save 65 gallons a year, more than paying for the device’s $199 cost. The product comes from the former CEO of Superchips, so the engineering and development behind Range appear to be of top quality. The Range is clearly not an enthusiast’s garage hack. Instead, it’s a quality product that has undergone comprehensive testing. Because the Range does not override any engine safety parameters, Range Technology claims the device cannot harm your vehicle at all. Unboxing Good packaging is always important for any new product. When a consumer is paying nearly $200, the look and feel of a product’s box is critical. Range Technology seemed to recognize this and made unboxing the Range a satisfying experience. The Range comes in a high quality soft-touch cardboard box with minimal exterior logos and stickers. Just a silver range logo and product serial number adorn the outside. Cutting two clear stickers allow the top half of the box to separate from the bottom. Inside, you’ll find the Range front and center. A simple instruction card is slid behind the device. The product is displayed nicely and is easy to access. In short, the Range is packaged in a modern manner you’d expect from a $199 device. Installation Installing the Range is super easy and takes only a couple seconds. Just take the range out to your vehicle and open the drivers door. Look under the steering wheel and find your diagnostic port. Plug the Range into the diagnostic port while the vehicle is off. You should see a blue LED light up on the device and you’re good to go! Uninstalling the Range is just as easy. With the vehicle off, just unplug the device. Your vehicle’s active-fuel-management system will revert back to stock operation. First impressions As with any product that only takes a few seconds to install, it’s initially hard to believe that the Range could make any negligible difference. With the claims being made, we were initially skeptical. A few miles behind the wheel and down the road, our skepticism dissolved. Once the 5.3L V8 in Project Sierra warmed up, the Range kicked in. Our Sierra’s engine kicked down to V4 mode, just as always, but there was a noticeable difference in the time the system would stay engaged. No longer does a slight tip of the throttle “deactivate” AFM. The Range device held V4 mode longer, through more throttle, and even allowed us to travel up hills and accelerate. It’s a huge difference from stock, when any little incline or acceleration used to kick the engine into all eight cylinders with ease. Staying in 4 cylinder mode substantially longer does come with a few drawbacks. With only half the engine running noise, vibration, and exhaust drone are increased. It’s not harsh but very noticeable. These are the standard complaints we’ve heard of active-fuel-management in the past and part of the reason why some people detest it. We’ll consider these compromises as we continue to test the Range. Does it actually work? It’s immediately obvious that the Range does substantially increase the time Project Sierra runs in four-cylinder mode. Will that work out to increased fuel economy? Current Range customers say yes but we’re going to find out for ourselves firsthand. During the coming weeks we’re going to run the Range on Project Sierra. After a couple tanks of gas and a few calculations, we’ll see what effect it has. Because we’ve kept records of every single fill up in our truck any change in fuel economy, good or bad, will be easy to see. We’re report back when we have our final results. While we’re out testing, check out the product on the Range Technology’s website for yourself. We’ve also got a discussion going on this article in the GM-Trucks.com forum. We’ll be updating forum members with fuel economy numbers on a tank by tank basis, so cruise on over to our Project Sierra section and get the inside scoop on how things are progressing.

By Zane Merva Executive Editor, GM-Trucks.com 1/5/2015 GM Ventures is taking the wraps off brand new technology designed to take the company's existing Active Fuel Management system into a new software-only era. A 2012 GM Ventures Equity Investment, Tula Technology, Inc has developed a unique digital control system that can "skip" cylinders firing to save fuel. It's called Dynamic Skip Fire (DSF) and it may change everything you know about how an internal combustion engine fires. The press release says it best: "Instead of relying on fixed cylinder deactivation or switching between fixed patterns like current multi-cylinder engines, Tula’s DSF technology continuously makes dynamic firing decisions on an individual cylinder basis to deliver the required engine torque for all vehicle speeds and loads while avoiding vibration. Independent testing commissioned by Tula shows that the application of DSF technology can improve fuel efficiency in a multi-cylinder engine (4/6/8 cylinders) by as much as 15 percent when compared to a vehicle equipped with an engine that does not have cylinder deactivation." In short, GM has replicated the mechanical attributes of displacement on demand with a digital software solution. Will this technology see the light of day in the future? We sure hope so.

Zane & Josh Merva Copyright, GM-Trucks.com A few months ago we gave you our first impressions of the Range, a device designed to enable the active-fuel-management system on your GM 5.3L engine to run more often. Since then we’ve been using the device and recently ran a fuel economy comparison to see how well it works. Since January we’ve been driving our 2011 5.3L Sierra using the Range AFM extender module plugged into our OBDII port. It has made a significant difference in the way our truck drives in nearly all circumstances. We’ve driven over a thousand miles with the device and here’s what we can tell you about our experience with it. First off, the Range does exactly what it states it will do. With the device, our Sierra always tries its hardest to use the active fuel management system (AFM) and engages V4 mode more aggressively than stock. How the device works through the diagnostic port is a little bit of a company secret but the change is entirely reversible, untraceable, and does not damage your engine. When plugged in, the device slightly modifies the signal to your vehicle’s computer, but leaves no lasting changes when unplugged. We’ve long noticed our AFM equipped 5.3L V8 is a fickle beast to keep on four-cylinders, even when we try really hard. The Range “changes” the way AFM works, making it easy to take advantage of the feature. In our experience once AFM is engaged using the Range, the truck fights to stay on four-cylinders through a much wider spectrum of throttle than you’d experience normally. On flat or slightly uphill grades, we could easily keep speed and even accelerate while on four-cylinders using the Range. That’s something we could never do with stock AFM programming. So, while stock AFM always seemed hesitant to stay in four-cylinders, the Range makes our 5.3L act different . With the Range V4 Max, our truck tries to run with four cylinders whenever possible. What makes the Range work, keeping AFM active more often, does come with some minor drawbacks. Most noticeably, the transition between V4 and V8 mode can be harsh and abrupt at times. Where GM engineering designed stock AFM tuning to work smoothly, Range engineers focus on keeping AFM engaged longer for better fuel economy at the expense of refinement. Not surprisingly, in four-cylinder mode our Sierra also felt underpowered. After all, it is running on 1/2 the engine size and longer than GM had intended. On flat roads and highways, that turned out to not be a problem. However, driving with the Range required slightly more mental effort to keep our Sierra moving at speed whenever we drove uphill or through hilly terrain. Whenever we did need extra power,the Range always engaged V8 mode quickly without delay. We also tried towing a small trailer while using the Range but would not recommend it for longer periods of time when engine performance is critical. Heavy loading seems to cause the system to switch between V4 and V8 too often. Thankfully, unplugging the Range while you’re towing is easy. Another oddity was that since it’s always plugged into the vehicle’s diagnostic port, we had false errors show up in our monthly OnStar Vehicle Health Report while using the Range. Most noticeably, OnStar could not read for trouble codes and RemoteLink could not access tire-pressure data. While annoying, there was no damage done and these errors fix themselves when the device is removed. We’re told this is expected behavior, as devices connected to a vehicle’s diagnostic port have the ability to override other vehicle computers. For all the change in the way our Sierra drove, without a daily commute (we work from home), our short and irregular trips around town made it hard to see any direct fuel economy improvement during the winter. While we could always feel the Range working, we quickly realized that through short trips and 4×4 use, our fuel economy actually dropped. Combined with cold temperatures and winter grade gas, the deck was stacked against us getting any real world improvement. We knew that the Range should be producing fuel economy gains but our driving schedule, style, and inclement weather made it impossible to see in hard data. So, as the weather has gotten warmer, we wanted to do a little test. While not scientific, our first idea was to perform a back to back driving loop. We wanted to get an idea of how the Range stacked up to stock, outside of the random short trips and winter driving we had encountered over the last few months. We drove Project Sierra over a predetermined rural and highway road loop to gauge how well the Range worked versus stock AFM programming. Driving the same roads back to back, allowed us to compare fuel economy using the same driver, road conditions, and weather. Both runs started and ended at a gas station so each loop would be tested using the same fuel weight. Our Sierra was also fully warmed up before starting. For consistency, we completed each loop in nearly identical time and average speed, measured via GPS. Through concentration and a little bit of luck, only 50-seconds and 0.6mph differed between the two back to back runs. All effort was made to drive our Sierra in the same manner for each loop. After only 60 miles, the results came out clearer than we expected for an unscientific test. Stock, we completed a 30.8 mile loop in 44:21 minutes at an average speed of 41.64mph. During this loop our Sierra recorded an average fuel economy of 20.9-mpg, as displayed via the driver-information-center. With the Range, our 30.8 mile loop was completed in a comparable 45:10 minutes at an average speed of 40.9mph. With the same driver, same road, and same weather, we saw a DIC reported average of 21.4mpg. That comes to a healthy ½-mpg improvement. Also impressive, considering we’ve never gotten fuel economy that high out of Project Sierra in the past during any time of the year. Until now, our lifetime fuel economy average for our 2011 Sierra has been around 16mpg, as reported by OnStar. During the winter with our short trips and four-wheel-drive use, we often saw that figure dip to 14mpg or worse. While we always caution folks to not rely on driver-information-center fuel economy, a number north of 21mpg is impressive for comparisons sake. So is 30 miles enough to say the Range definitively works? Scientifically, no. However we wanted to see, under a controlled route, if the Range made any improvement at all. Not surprisingly it did. Since our quick loop we’ve burned several tanks of gas with the Range V4 Max and our experience remained consistent. Depending on what type of rear end gears, transmission, and what route you drive, the average driver should see a fuel economy improvement while the device is in use. Since everyone’s driving style is different, it’s hard for us to tell you exactly how much the Range will effect your own fuel economy. Our 6-speed automatic equipped Sierra ran great with the Range V4 Max Module but if you have an older 4-speed automatic, try out the company’s Range V4 Plus module. The V4 Plus is described as better tuned on the highway for vehicles with less transmission gears. Don’t take our word for it, read this thread for other member experiences with the line up of Range Modules. Do you have a Range? Comment and let us know. We want to hear what other Range owners are experiencing. Do you loathe AFM? If you’re looking for the exact opposite effect, disabling AFM entirely, we’ll be testing Range’s V8 only option in the near future. GM-Trucks.com Range V4 Max Hands-On Conclusion The Range does exactly what it claims to but it’s not a magic bullet. Used as a tool, the device allows you to take advantage of your trucks ability to run on fewer cylinders. In our personal experience that can lead to better fuel economy depending on how and where you drive your truck.