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Range AFM Battery Drain Fix

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Hey Guys, I have had my 2015 Sierra for a year and a half now and I cannot stand how the truck shifts through the gears. I have been researching the forums for different fixes or something to help make the truck drive smoother. Long story short, I find that the Range AFM v4 disabler is the best solution available that avoids voiding my warranty. I do not use my truck as my primary vehicle and only put about 7,000 miles on it a year, so I do not want to void my warranty far before it expires considering all the quirks, Direct injection, and other things the warranty could save me $thousands if something breaks.


I find that the truck drives around town much smoother without it going in and out of v4/v8 modes and the trans does a much better job managing city driving. So what is the major downfall of the Range AFM Disabler? It drains the battery, especially for someone like me who only drives on weekends. Between Christmas and New Years I had the time to figure something out. In our truck one of the pins in our OBD2 connector provide a constant 12v, which the RangeAFM uses for power. I came up with a relay design that only provides power to this obd2 pin only when the ignition is on, theoretically preventing the RangeAFM from draining my battery when the truck sits.


***Please beware this is a mod I decided to do to my truck and so far I have not had an issues. Modifying your own truck is your responsibility, not mine.***


Some Key points about the mod:

1. Provides the same power source as always, but only allows the OBD2 pin to access the power source when ignition is on.

2. I have an optional switch that will provide the original constant power to that pin in the OBD2 plug. The reason I did this is because I have dealer oil changes and I want everything to operate as the truck is designed to when they connect to my OBD2 port. The switch bypasses the relay control, therefore allowing factory operation. Before my dealer visits, I removed the RangeAFM, and flip the switch. You can place your switch anywhere, mine is hidden.

3. When cutting the wire from pin 16, I soldered and heat shrink my connections, and wrap it back up with the same fabric tape GM uses. The reliability of this mod depends on your ability and skills.

4. Not that this is a big deal, but when I get my GMC email/report every month it does not show there are issues since the RangeAFM is off while the truck is sitting.


Thanks again to everyone on the forms for your input that led me to this decision. When my warranty is up I cannot wait to program/tune the truck, but for now I am happy with these results.





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It's a nice accessory but it still requires you to remember to turn off the obd2 port off with that switch. I was looking for a solution that does not require me to remember to turn it on or off.

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Mike1ch ,so this works on 2017 5.3 silverado's? you have pics of your wiring work?so pin #16 is not needed for range delete to work? thanks


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It should work but I don't have a 2017 Silverado to test it on. Pin 16 is where the AFM gets power from the OBDII plug. The wiring diagram from my first post is the best way I can describe how to wire this relay. If you are not 100% sure what to do, please don't start cutting your factory wires. Consult a car audio shop or a Best Buy or PC Richards and show them the above diagram.

Sorry I don't have any pictures of the work.

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