V8 & V4 .. showing on DIC

[Someone]

Why does sometimes it shows V4 and sometime V8 on the DIC. (see pics)

[I have recently bought 2015 Tahoe LS 2x4 without user manual]

 

[PG01]

DOD displacement on demand, AFM Active fuel mgmt, shuts of 4 cylinders to give you better gas mileage........hahahahahahahahahahahahaha.....do a search on here for AFM or google.......lolololololololol

 

[Glocksub]

DOD displacement on demand, AFM Active fuel mgmt, shuts of 4 cylinders to give you better gas mileage........hahahahahahahahahahahahaha.....do a search on here for AFM or google.......lolololololololol

Exactly. My advice is to disable it using a range device, superchips or diablo programmer. It will drive better without it and most report that the change in fuel mileage (if any) is well worth the improved drive ability.

 

[jeffbco]

Obviously his selling dealer didn't explain the "benefits" of AFM or he didn't get an owner's manual.

Active Fuel Management®

Vehicles with V8 engines may have

Active Fuel Management. This

system allows the engine to operate

on either all or half of its cylinders,

depending on the driving conditions.

When less power is required, such

as cruising at a constant vehicle

speed, the system will operate in

the half cylinder mode, allowing the

vehicle to achieve better fuel

economy. When greater power

demands are required, such as

accelerating from a stop, passing,

or merging onto a freeway, the

system will maintain full-cylinder

operation.

If the vehicle has an Active Fuel

Management indicator, see Driver

Information Center (DIC) 0 152 for

more information on using this

display

 

[PG01]

Can i like something i unlike????????

 

[sumo]

On paper it's a great idea. Real world use is doesn't work. Sure if you let off the gas or coasting downhill will show all day long. Touch the gas pedal, back into v8 mode

 

[2011SSVHOE]

remember the Cadilac V8-6-4 ? what a disaster , you would of thougt they learned. I think that was 1981

 

[Z15]

Its a more fuel saving device for GM CAFE then for the customer. Its things like this, 8 & 10 speed trans or a V6 like Furd.

 

[aJohnM1948]

Why does sometimes it shows V4 and sometime V8 on the DIC. (see pics)

[I have recently bought 2015 Tahoe LS 2x4 without user manual]View attachment 80350 View attachment 80351

My 2018 Tahoe LS had a V8/V4 indicator on certain pages of the DIC. I can’t find an indicator like this on my 2025. Is Chevy trying to pretend cylinder deactivation doesn’t exist because of the problems it can cause? I read previously it caused problems in 2% of prior generation vehicles and never read a root cause. Was it variation in machining tolerances (my bet), dirty oil, driving habits, something other? I could always connect my Autel OBD2 meter on to monitor cylinder deactivation if I wanted to ensure an after market product like a Range DOD/DFM device is doing it’s job of keeping the car in V8 mode, but that’s a PIA if one would have to do that periodically to insure such devices were (still) doing their job.

 

[Marky Dissod]

My 2018 Tahoe LS had a V8/V4 indicator on certain pages of the DIC. I can’t find an indicator like this on my 2025.
Is Chevy trying to pretend cylinder deactivation doesn’t exist because of the problems it can cause?

Engines with V8 & V4 mode only need a V8 or V4 mode indicator.
Engines with V8, V7, V6, V5, V4, V3, V2, & I2 modes would need a far more complex indicator.

I read previously it caused problems in 2% of prior generation vehicles and never read a root cause.
Was it variation in machining tolerances (my bet), dirty oil, driving habits, something other?

Very early ChrysCo Hemi V8s left V4 mode enabled for far too long. The lazy cylinders cooled considerably.
Eventually, the cool cylinders vs hot cylinders temp differential would crack cylinder cases open.

I had my ecm tuned specifically to increase my V8's V4 duty cycle,
so that it was obvious to my butt when it was in V4 mode - the goal was to improve MpGs.
This worked for about one year, but the MpG benefits waned over time. Then I noticed higher oil consumption.
Too much V4 mode caused the lazier cylinders to wear worse than the full-time cylinders.

GM tried to improve on that weakness by not letting any one cylinder cool more than any other.
Dynamic Skip Fire (GM calls it Dynamic Fuel Management) keeps consistent temps from cylinder to cylinder.

What has not improved are cam lobe hardening techniques, lifter bore machining,
and lifter construction and quality control.
Cam lobes that are not properly hardened can wear away at lifters' undersides.
If a lifter bore is not machined properly, it can let a lifter change orientation in its bore.
Since every cylinder is now deactivate-able, any lifter could potentially wear away from too many deactivations,
especially if the motor oil is not changed often enough.