Disable AFM

[AWSMBLU]

https://gmauthority.com/blog/2025/02/little-known-chevy-silverado-tahoe-suburban-trick-disables-dfm/

 

[Joseph Garcia]

Interesting. Who knew? Could be a good way to temporarily eliminate DFM functionality, while waiting or preparing physical work for its complete elimination.

 

[AWSMBLU]

Interesting. Who knew? Could be a good way to temporarily eliminate DFM functionality, while waiting or preparing physical work for its complete elimination.

It also disabled the start stop

 

[DontTaseMeBro]

Interesting. Who knew? Could be a good way to temporarily eliminate DFM functionality, while waiting or preparing physical work for its complete elimination.

Joe, it’s been well documented across multiple threads in this sub-forum.

Take this one for example:

Driving in L9 and DFM

Greetings all Has anyone confirmed if driving in L9 will disable DFM? I haven't been able to find anything on the forums and haven't noticed whether it works or not . I have tried it but can not confirm for sure seeing that there is no indicator stating such. Plenty of older trucks that do...

www.tahoeyukonforum.com

 

[Joseph Garcia]

Joe, it’s been well documented across multiple threads in this sub-forum.

Take this one for example:

Driving in L9 and DFM

Greetings all Has anyone confirmed if driving in L9 will disable DFM? I haven't been able to find anything on the forums and haven't noticed whether it works or not . I have tried it but can not confirm for sure seeing that there is no indicator stating such. Plenty of older trucks that do...

www.tahoeyukonforum.com

It was news to me, so it may be news to others. I don't know all of the answers, and I look forward to learning something new every day.

 

[RG23RST]

Yes that's been a thing even going back to the 6 speed units a decade ago.

It "shouldn't" hurt anything but at the same time I'm not sure I would guinea pig myself for 100K miles running on the highway in 9th gear with the E clutch applied. Probably a non-issue though.

 

[swathdiver]

Yep same as running in M5 with the 6-speeds.

Well, the EPA will no longer enforce the Clean Air Act and GM and the others will likely get rid of AFM from new production engines soon enough.

 

[PPV_2018]

Yep same as running in M5 with the 6-speeds.

Well, the EPA will no longer enforce the Clean Air Act and GM and the others will likely get rid of AFM from new production engines soon enough.

Yeah i wouldn’t count on that. I can’t see gm deleting afm from future production considering the possibility of the next U.S. administration reinstating tighter emissions rules. That would cost gm lotsa “zeros” whereas it would be cheaper for them just to keep this already established “technology” under the guise of saving you, the consumer, money on fuel.



At any rate, this thread should be a sticky, for those who are unaware.

 

[swathdiver]

Yeah i wouldn’t count on that. I can’t see gm deleting afm from future production considering the possibility of the next U.S. administration reinstating tighter emissions rules. That would cost gm lotsa “zeros” whereas it would be cheaper for them just to keep this already established “technology” under the guise of saving you, the consumer, money on fuel.



At any rate, this thread should be a sticky, for those who are unaware.

Or they could delete it and offer vehicles for less money while increasing their profits. We shall see.

 

[RG23RST]

N

Yep same as running in M5 with the 6-speeds.

Well, the EPA will no longer enforce the Clean Air Act and GM and the others will likely get rid of AFM from new production engines soon enough.

Not how that works. CAA is Congressional legislation and isn't going anywhere. GM gets the 5.3 to ULEV50 with DFM and they sell that engine in other markets so there's no point in having multiple versions. Whichever way GM wants to meet the law is up to them. Big gov doesn't require cylinder deactivation but it helps meet the target. Ford went the opposite route for their volume engines (2.7 and 3.5) with smaller displacement and sell relatively few V8s now even though those have cylinder deactivation too.

What little has trickled down to us concerning the new engines for 27/28 indicates they'll still employ the deactivation technology along with cooled EGR which has been on the Ford stuff for a few years now. That's secondhand information from the bosses that attend dealer shows so take it for what it's worth.