2023 Premier Cylinder Deactivation Questions

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Capt Ed

TYF Newbie
Joined
Feb 26, 2024
Posts
22
Reaction score
11
First, should I be getting a notification on dashboard when engine deactivates cylinders? I don't get anything now.

Second, I've read if I run in 9th gear it will deactivate the DFM? If true, how do I do this?
 

fondupot

Member
Joined
Oct 31, 2024
Posts
61
Reaction score
90
Location
South Carolina
I don't think the newer trucks show on the cluster when it goes into AFM/DFM.

You can run in L9. Put the truck into "L" gear and then use the plus button to put it on 9. This locks out 10th gear and disables the AFM/DFM
 

Marky Dissod

Full Access Member
Joined
Mar 3, 2023
Posts
1,902
Reaction score
2,611
Location
(718)-
1st, should I be getting a notification on dashboard when engine deactivates cylinders? I don't get anything now.
No, because GM regrets letting drivers know when the vehicle was in V4 mode vs V8 mode,
which gave some drivers additional ability to correlate symptoms to V4 mode, or transitions between.

Plus your engine has V8, V7, V6, V5, V4, V3, and V2 modes (SEVENTEEN different firing orders, actually!).
GM are saving themselves the expense and labor of giving you additional potential complaint reference points.
 

Antonm

Full Access Member
Joined
Apr 2, 2024
Posts
170
Reaction score
194
Not telling the customer/driver the full story is not a new concept in the automotive world.

Just one example, Dodge did this back in the mid-90's ( which was 30 years ago now). The Cummins trucks had larger radiators so they could cool the engine while towing (because that's what you should be doing with a diesel truck anyway). Well, driving around empty and unloaded the temp gauge would rise to thermostat opening temp, the thermostat would open, then the temp gauge would quickly fall, the thermostat would close and the cycle would star all over again. Perfectly normal if you're driving a big diesel truck around now hauling or towing anything. But people would ***** and complain that something wasn't right, and constantly be bringing trucks back for warranty work when nothing was wrong. So Dodge changed the temperature gauge in the next update to be basically be an idiot light with a needle. Temp gauge just goes to the middle of the range unless the computer tells it to peg high from an overheat condition. The customers complained, so Dodge fixed the issue by not telling them what was actually going on anymore.

Can't really blame them or GM though. People complain about a lot of stuff that's just impossible, plenty of internet YouTube clips to prove that. Just the other day I saw a YouTube clip were a woman was complaining that the redline of the tachometer was different after getting a battery changed out. It wasn't a digital dash or anything, literally colored plastic , but she swore the redline wasn't there when she dropped the car off for a new battery and she wanted a refund and for them to pay to fix it. The poor tech didn't know what to tell this idiot lady. Sadly, I'd bet dealers deal more with these total automotive idiots than they do with people that have any clue what's going on with their vehicles.
...
 
Last edited:
Top