Question about DFM programming in regards to the ECM?

Cojam1 · June 13

The newer trucks/suvs have the latest GM Global B architecture. No one has a solution yet to deactivate DFM. For a period of time during Covid situation GM shipped vehicles with DFM deactivated from the factory. I had one. My question is to anyone of the GM techs or Professional Tuners on the forum or anyone with expertise on this matter. Can the DFM be deactivated at the dealership with their computer/software. I know the computers give them full control of the ECM parameters, and I know they won't do it, but I'm curious as to if the ability is there.

joshhibschman · June 19

A GM Master Tech told me "we can't do it," but he didn't say "it can't be done." He added:
- Blocks still fail from mechanical DFM even if ECM disabled.

- Full disable requires different lifters, head gaskets, etc.

- All flashes to the ECM show up in history, can be tracked by who did it

- Third party flashes will void your warranty (i.e. HP-Tuners)
- As of Global B, access to the ECM is encrypted

Update -- For DIY electronic and mechanical, the cost appears to be ~$2,000 and 20+ labor hours for an experienced mechanic, also having to pull out and send in your ECM. Wish I had infinite free time to try! Will keep watching for someone to post experience with these products and circle back.

DIY Electronic Disable
HPTuners released send-in program for Global B ECMs! You have to pull out your ECM, send it in, and they "upgrade" it with a chipboard harness. Thing's you'll need:
- Being OK with voiding your warranty
- Couple weeks turnaround without your truck (pull and send in your ECM)

- $800 for 22-24 L87 ECM mod: https://www.hptuners.com/product/gm-e90-ecm-service-global-b/

- $400 for the OBD2 connector: https://www.hptuners.com/mpvi3/#custom_form_mpvi2
- $300 ($400 on Yukons) for 6 License Credits https://www.hptuners.com/vehicles/#supported-vehicles
- A Windows laptop to run their VCM Suite (free download)

DIY Mechanical Disable

Michigan Motorsports stocks a delete kit for L87. Don't know if this 2019+ kit actually goes to 2021 or if it still works through 2024. Should call and ask.
- $400 Mechanical Lifter Delete Kit https://www.michiganmotorsports.com/camshafts-michigan-motorsports/cam-installation-items/2019-l87-6-2-dfm-lifter-delete-kit-dod-afm-6-2l-gen-v-kit/

Supplemental Notes on Non-DFM Motor Failures

Many recent motor failures are coming from parts outside DFM/AFM/DOD.
- 2023 Oversized Lifter Bore Defect, i.e. the lifter tube is to big, lifter rocks, causes a bent rod
- 2022 Main Bearing Cap Bolt Defect, i.e. bad torque on the bolts, misaligns the crankshaft
- 19-23 Oil Pump Defect, i.e. bad oil pressure, bad lifter activation
- 2021 Plunger Spring Rod Wear , i.e. lifter spring rubs rod, causes a bent rod
- Gas/Oil low on detergents lets carbon build up, jamming the lock-spring in the lifters

Edited June 24 by joshhibschman

joshhibschman · June 24

@Cojam1 I posted an update after asking around a bit more over on hp-tuners forums

Cojam1 · June 24

Thanks for the detail information and reply. My Brand new truck experienced lifter failure before my first oil change. This is my 2nd L87 vehicle and my third gm v8 that has had this issue. I've been a die hard GM fan but my patience is wearing thin. GM customer service has been sub par so far. I will look into those links. Thanks again.