AFM/DOD Questions

I just bought a 2017 Yukon XL with the 6.2 and 170K miles. It seems to run good, has what seems to be a very subtle stumble or misfire type vibration at idle that Im not sure what is causing but my question here would be, is there a way to tell if the AFM/DOD program is still active or has already been deleted from the ECM? If its still active should I have it erased from the ECM like the link below offers?

Engine Half@$$ / Cylinder Confusion does NOT operate at idle.
Misfire @ idle? Find the trouble code. If it points to a specific cylinder, try swapping coils.
If the code follows the coil, replace that coil, then buy the other 7 replacement coils; doubt they'll get cheaper.
You can also try swapping wires.

Separate from the above, disable Engine Half@$$ / Cylinder Confusion at your earliest opportunity.
The driver instrument cluster may allow you to press a sequence of buttons that will let you see if the engine is Full @$$ or Half@$$,
but I don't know if the DIC will let you see if Cylinder Confusion is in effect.

No dummy lights are on, but if a misfire I supposed a high end 2nd level scanner would be able to detect that. I’d have to take it to a shop for that. Not sure if that is the problem or if they just idle this way

I think my ‘17 has the 2nd variation which is the “dynamic” system correct so most likely no way to see if that system is active or not currently?

To disable, is it better to use an OBD port plug in module or one of the services that will re program my ecu like the link? Obviously it’s a band aid since the mechanical parts are still present but I’m not going to test into the motor until needed, knock on wood haha.

Don't laugh at Engine Confusion! Might get pist off.
If the ONLY thing you care about is fulltime V8 mode, a plug in will do just fine.
There might even be a cheaper way to do it, disconnecting a vacuum line somewhere under the hood ... ?
If you want more, you need a proper ecu reprogramming. You get SO MUCH MORE with an ecu tune, it's not even funny.
(If you reprogram, raise the Engine Confusion enable temp to 230F, might delay an overheat condition.)

By ecu tune do you mean something like this with there level 2 kit etc or a full on chassis Dyno tune session?


It’s stock for the most part and while I’d love to go all out on a new 6.2 LS I have to remember it’s my wife’s vehicle so I gotta leave the tinkering to my toys.

What they are willing to offer for $121 is mildly impressive, BUT
no one said anything about going all out.
It's entirely possible to get an ECM AND TCM TUNE that your wife would only notice if she stepped on the go-pedal harder than she normally does,
and would then convince herself that she was wrong as soon as she relaxed on the go-pedal.

A thorough and proper tune by a tuner worth their weight in lasagna, is as mild or as wild as the customer and the tuner AGREE it is.
It's not about going all out - it's about making the owner happier than GM's onesizefitsanyone guess.
You've been to Five Guys Burger, yeah? You're in charge of the details, yeah?
That's how a tune is supposed to be.
A good tuner can make a tune for a hypermiler, a parent forced to buy a sports car for their kid, or a tow-elephant.

A friend just warned me that here in CA at least, the scanners used for our Smog/emissions testing required every other year can detect if the ECU has been reprogrammed in anyway from stock and will fail and flag in the system. He said I should only get the type that is removable from the OBD port and unplug it a week or two prior to testing to allow for all the systems cycle as OE designed.

LOL, funny that CA thinks a few guys that disable their AFM will cause the climate to change. Honestly, it is such a small percentage that even do this. It's more about control than anything.

Absolutely! I love CA but hate those running it.

You can go to the screen on the DIC in the middle of the gauges that shows the MPG readouts and down in the corner it will show V8 or V4 mode active. The Range plug in disabler works fine on these machines. Son had a lifter making noise, scared him, he put some Sea Foam in the engine and got the Range device and it's been perfect now for 20K miles or so.