Has anyone disabled the AFM in their GMC Yukon either by driving in "M" mode instead of "D" or installing a disabler on the OBD port?

[testdepth]

I'm wondering if the problem I'm having is to do with the Active Fuel Management system in my 2012 Yukon Denali with a 6.2L and 6 speed transmission?

An aftermarket disabler can be installed on the OBD port to disable AFM and drive with V8 all the time instead of the constant shifting to a 4 cylinder and back to V8.

Google shows you can disable the AFM for free by shifting the transmission to "M" (5) for my transmission. This is supposed to keep the engine in V8 mode only.

 

[JBob44]

I'm wondering if the problem I'm having is to do with the Active Fuel Management system in my 2012 Yukon Denali with a 6.2L and 6 speed transmission?

An aftermarket disabler can be installed on the OBD port to disable AFM and drive with V8 all the time instead of the constant shifting to a 4 cylinder and back to V8.

Google shows you can disable the AFM for free by shifting the transmission to "M" (5) for my transmission. This is supposed to keep the engine in V8 mode only.

I have a 5.3 with 6 speed, have had a AFM/DOD disabler in for quite some time and it does what it is suppose to, have suffered no downside. The purist will tell you properly delete the AFM/DOD instead of just disabling it. The disablers range from $30-200, they all do the same thing.

 

[testdepth]

My AFM generally only kicks in when I let off the gas pedal. I just test drove it in "D" and watched my display show it was in V8 mode all the way to 75mph. Never once shifted to V4. As long as I maintained gas pedal pressure it stayed at V8. As soon as I let off the gas pedal it shifts to V4 and if I never touch the gas pedal it will stay at V4 until about 42mph and it will shift to V8 and drop to V4 at 25mph and then back to V8. I drove it on the HWY in "D" and accelerated to 75mph and maintained speed with my foot and the engine stayed in V8. At 75mph when I let off the gas pedal the engine shifts to V4 and stays there until either I press the gas pedal or the engine speed drops to about 42mph and then it will shift back to V8. At anytime I start to decelerate the speed the engine shifts from V8 to V4.

I thought this system was suppose to shut 4 cylinders off at steady HWY speeds but this one stays at V8 until I decelerate??

 

[JBob44]

My AFM generally only kicks in when I let off the gas pedal. I just test drove it in "D" and watched my display show it was in V8 mode all the way to 75mph. Never once shifted to V4. As long as I maintained gas pedal pressure it stayed at V8. As soon as I let off the gas pedal it shifts to V4 and if I never touch the gas pedal it will stay at V4 until about 42mph and it will shift to V8 and drop to V4 at 25mph and then back to V8. I drove it on the HWY in "D" and accelerated to 75mph and maintained speed with my foot and the engine stayed in V8. At 75mph when I let off the gas pedal the engine shifts to V4 and stays there until either I press the gas pedal or the engine speed drops to about 42mph and then it will shift back to V8. At anytime I start to decelerate the speed the engine shifts from V8 to V4.

I thought this system was suppose to shut 4 cylinders off at steady HWY speeds but this one stays at V8 until I decelerate??

Cant remember exactly how mine did. I know it would stay in V8 at idle, once about 25 mph or so and under light load i think it would drop to V4. It would drop to V4 at HWY speeds 55-60 as long as you were not going up a grade or downshifting etc. I feel like anytime you when more than about 15-25% throttle after traveling a steady speed it would go back into V8 mode. The AFM disabler just helps the truck feel less jerky and hopefully prolongs and possible lifter failures.

There is a guy on here out of Cobb County that tunes out the AFM and does Trans tunes as well on these trucks. Haven't used him but i remember seeing his post in the past.

 

[basstracker89]

I hate to say this, but I think it's time to cut your losses on this one. I'm sorry. I'm sure most feel this way by now. I had my doubts when you thought it was fixed last time. This new computer stuff is great if it's working right. But if it's not.......It's a real nightmare. I've been thinking your just throwing good money after bad in it.
Now if you could retro the vehicle back to old mechanical standards, you might have somethin. But with these newer cars, it's not near as easy. And it's expensive too. Like my old 94, it'd probably cost $6k. I spent $4k fixing the problems. It's not perfect, but it's 98-99%

 

[MCurtis762]

Just curious. How much money have you put into parts chasing this issue?

Have you looked at a data logger yet? You'll be able to see exactly what the computer sees when the intermittent issue pops up.

 

[testdepth]

I just installed a BOOST AFM disable (made in Merica) device for V8 all the time. We just ran down the road and back with no problems.

As for all of the parts I threw at this truck to fix it's issues over the last month I just look at it as upgrading 13yr old parts to new ones. We have owned this truck for 10yrs.

 

[MCurtis762]

I had an 09 Sierra with a 4.8. Sold it at 230,000 miles and all it ever needed was brakes, shocks, and a driver's window switch. Just trying to help you save some money and frustration. Firing the parts cannon gets expensive eventually.

 

[basstracker89]

I just installed a BOOST AFM disable (made in Merica) device for V8 all the time. We just ran down the road and back with no problems.

As for all of the parts I threw at this truck to fix it's issues over the last month I just look at it as upgrading 13yr old parts to new ones. We have owned this truck for 10yrs.

I didn't realize it was one of those...... I hope it fixes it