Jump to content

Pulling DFM fuses

03blackz71
 Share

Recommended Posts

03blackz71 Senior Enthusiast

03blackz71

Posted
  • Author
Posted
18 hours ago, Firehawk99 said:

Well I tried this and my truck ran like crap! It was shifting all wonky and started hard. I put them back in and it's back to normal. I have a 21 6.2 trail boss.

 

I think the fuse numbers are for the 5.3l.     The 6.2l might be different.

 

 

  • Replies 67
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

BlancoSilverado
BlancoSilverado

Alright everyone,    First went for a drive and verified that i can see the DFM activate, which i saw. i am using an Autel MP808   i pulled over shut off the engine pulled fuse 60

voided3
voided3

That's a bummer. I would be so happy if there was a way to make it so "D" was the same as "L7" on the gear selector so I wouldn't have to toggle up every single time.  I'd be even happier if cylinder

Firehawk99
Firehawk99

Well I tried this and my truck ran like crap! It was shifting all wonky and started hard. I put them back in and it's back to normal. I have a 21 6.2 trail boss.

Posted Images

WeGone Enthusiast

WeGone

Posted
Posted
1 hour ago, 03blackz71 said:

 

I think the fuse numbers are for the 5.3l.     The 6.2l might be different.

 

 

 

Can anyone confirm on 6.2?

Silverado4x4 Senior Enthusiast

Silverado4x4

Posted
Posted (edited)
19 minutes ago, WeGone said:

 

Can anyone confirm on 6.2?

Nope same fuse numbers. If you're unsure the fuse numbers are in the back part of your owner's manual.

Edited by Silverado4x4
  • Thanks 1
JohnH4260 Enthusiast

JohnH4260

Posted
Posted

The images below are from pages 352-354 in my 2021 GMC Sierra owners manual. In the engine compartment fuse box, it shows #60 and #67 are the Active Fuel Management 1 and Active Fuel Management 2 fuses. Maybe there’s another system involved as well. 

054858C1-D349-4FBE-BED9-F98DB474D369.jpeg

EB5C8F19-6556-4F7D-8FEF-3BF953F783B2.jpeg

D979D0BA-671D-41DA-A930-CF3E7C01D056.jpeg

kmeleon Enthusiast

kmeleon

Posted
Posted

I hooked up to my Bluetooth scan tool yesterday and I cannot see anyway to monitor how many cylinders are active in real time. I do believe pulling the fuses works but I have no way of proving it. 

RedLT Enthusiast

RedLT

Posted
Posted
On 12/19/2021 at 3:42 PM, voided3 said:

Driving in L7 on the 8-speed or L9 on the 10-speed does disable DFM on the L84 5.3 or L87 6.2 with DFM.

 

Driving in L8 on the 8-speed or L10 on the 10-speed, however, does not; you have to lock out the final overdrive gear to disable it. Driving in L8 or L10 is the same as D on these trucks.

Sorry if it's a dumb question but what does driving in L7 do? The truck only shifts gears 1 through 7? Is DFM beneficial when traveling long distance and disable DFM (L7) when driving around town?

WeGone Enthusiast

WeGone

Posted
Posted

Its my understanding As long as your driving in one gear under the highest you have using L? the cylinder cancellation does not activate. I use L9 under 70mph.

voided3 Enthusiast

voided3

Posted
Posted
On 12/28/2021 at 10:51 AM, RedLT said:

Sorry if it's a dumb question but what does driving in L7 do? The truck only shifts gears 1 through 7? Is DFM beneficial when traveling long distance and disable DFM (L7) when driving around town?

Correct, using "L" limits your gear range. If you have L1 through L7 selected, DFM is disabled. If you are driving in D or L8, DFM is active. I drive in L7 all of the time, but our highway speed limits are only 55-65 around here. Our truck with the 3.23 rear end turns 1900 RPM at 65 MPH in 7th gear and I still squeak out 19 to 20 MPG on the highway.

BlancoSilverado Enthusiast

BlancoSilverado

Posted
Posted

I might try this in the next few days,

I do have a scan tool that tells me if the DFM is activated and which cylinders they are activated. I will also post any codes that become present. 

  • Like 1
WeGone Enthusiast

WeGone

Posted
Posted
1 hour ago, BlancoSilverado said:

I might try this in the next few days,

I do have a scan tool that tells me if the DFM is activated and which cylinders they are activated. I will also post any codes that become present. 

 

looking forward to the results.

kmeleon Enthusiast

kmeleon

Posted
Posted
8 hours ago, BlancoSilverado said:

I might try this in the next few days,

I do have a scan tool that tells me if the DFM is activated and which cylinders they are activated. I will also post any codes that become present. 

Please do! Nobody has been able to know for sure if this works. I'd like to know 100%

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Atlas
      The Peckish Synapse

      By Atlas · Posted

      There's some truth to the above, but also, she's selling fullsize trucks and bread/butter CUV's like hotcakes, meanwhile, extracting GM's pickups from the deep discounting sales game.   GM's stock has held its own during her tenure, and the more recent buybacks are delivering cash back to investors and signal confidence in their direction forward. Even with the EV losses.   GM is an example of a modern publicly traded company. The #1 goal of any publicly traded company is to deliver the most value possible to shareholders. Despite being a car company, building the best car isn't GM's path to delivering maximum shareholder value.   McDonalds doesn't make the best burger, or the best coffee.   I've mentioned in another thread, I really don't / won't ever understand Cadillac or Buick in a modern context. Both brands are completely dead to me. I'll cede that the Escalade is a nice SUV, but the brand and nameplate mean nothing to me, and GM will never persuade me to pay north of $170k for a gussied-up Tahoe or Burb. Other people don't mind doing that and that's their purview.   The C8 shares absolutely nothing in common with any other current Chevrolet or Corvette on the market. Since its introduction 8 years ago, it's developed quite the following. It did what other Corvettes couldn't do: reduce the average age of its buyer. GM has something there, and I see them investing in the car. They'd better not mess that up.   We've successfully derailed Grumpy's thread again, but I think this one is meant to be more of a random thought thread so a little wandering is probably OK.
    • Tyler Gibbs
      2027 GMC Sierra: Official Discussion

      By Tyler Gibbs · Posted

      Sliding doors ftw   Also, Sienna ftw as well.  The in-laws got a 2024-2025 recently when their 2019 sienna was totaled due to a deer back in June.  They've been getting 38-40mpg on the 65mph highway they live on.
    • xdieselmechanic
      07 yukon xl 6.2 stalls at hot idle and wont restart

      By xdieselmechanic · Posted

      Forgot to mention that this started after changing the oil I use mobile 1 full syn with mobile one filter but I did add pro lube additive and was the first time doing so and is making me wonder just can't see why that would matter
    • xdieselmechanic
      07 yukon xl 6.2 stalls at hot idle and wont restart

      By xdieselmechanic · Posted

      I apologize for long post put going to try to explain everything. Parts replaced so far: Cam sensor Crank sensor Cam phaser valve Cam phaser solenoid Fuel pump Maf 1 injector Pcm Pdm   So about 2 weeks ago coming off the highway my 2007 yukon xl with the 6.2 stalled and would restart. Had unit towed back to house and I messed around with relays and unit started. Drove it the next day and same thing. Had it towed again. Scanned unit and had code p0300 with misfire data showing mainly cylinder 7 but I know that won't cause a no start. Measure fuel pressure and found only 42 psi replaced pump to have unit stall again and not restart. This time I stayed on back roads and just waited for it to restart about 30 to 60 min. During this time I found I have no injector pulse but have good power at injectors. Started unplugging 1 injector at a time and found when unplugging cylinder 7 pulse came back so i changed injecto and same issue. Turns out unit just happen to ready to start at that time. Scanned into unit and found no reason for the pcm to take away injector pulse so I replaced the pcm and same issue. I figured timing sesnor controlled the injector pulse so I replaced both sensors and while I had the water pump of i replaced the vvt components while i was in there. Read multiple people have luck chaging the maf for this issue so I changed it. Unit still stalls to this day and loses injector pulse on the ground side when it does. Have noticed watching the live data the pcm is request injectors to fire via injector pwm value. I have redone the ground wires at the left bottom of the block knowing this was the ground location for the pcm but still no luck. I am a mechanic by trade but this is having me pull my hair out. If anyone has something to have me check I will gladly im not much of a parts thrower but im about to load the cannon
    • newdude
      auto mechanical driver's door unlock without pressing button? [2026 Silv. 1500 WT 4WD RC SB 2.7L]

      By newdude · Posted

      Actually.  Wait.   I just re-read your original post.  Are you talking from INSIDE the truck you have to hit unlock?  Or from the key fob?  I had assumed from the key fob.   IF you are talking the inside unlock button, I assume you are shifting to park and its not unlocking the doors?  If so, that is changed via the settings page in the radio.  Go to SETTINGS, then VEHICLE and then it should be under LOCKS or DOOR LOCKS or something like that.  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...