yet another E38 158 mph speedo OS question

[ssclone]

I have a 2013 E38 ecu with OS 12653674. its from a 2013 silverado with 5.3.
i am running a 2011 l96 6.0 with 2006 4l80e with a t42 tcu OS 24235341

when i first did the swap i had a t56. so i changed the transmission from "automatic" to "manual". of course i then got the 158 mph in scanner. I then decided to go back to an automatic and put the 80e in. did the segment swap and used an 08 express file from repository with a 4.8, 4l80e and e38 ecu. transmission shifts and works great, but i still have the 158 mph in scanner.

the other day i write entire to the original truck tune the ecu came with in hopes to get the mph to possibly be correct, and yet didnt work.

do i need a different OS to make this work? is there something i am missing? can i have the dealer flash a different os onto it?

I am having part throttle drivability issues, and i am thinking its because the ecu is looking for a speed and its stuck at 158.

attached is the working tune in progress. 4_29_2021, 7k shifts 26's conv lock, 7300 limiter_ny2.hpt

any help is appreciated.

thanks

aaron

[blindsquirrel]

You've got an incompatible mix-n-match there, from the pre-2009.5 TCM file and the post-2009.5 ECM & OS. There's a communications protocol change when they went from the early 63lb injector limit E38 to the late 127lb limit E38, you have to use an early ECM OS on early ECM hardware with an early TCM OS all together, or late/late/late. Mix-n-match will break it.

You need a post-2009.5 T42 file. Ideally, a post-2009.5 T42 4L80E file. I've looked all over and haven't found one of those, though. I did find a 2010 & 2011 Silverado w/T42, but 4L60E. TCM OSes are 24243357 & 24252956. If you can't find a true 4L80E file, the 60E OS with a relay harness is an option but it bugs me knowing it should be workable without that if only you could find the right file.

You can write-entire the TCM with a different OS just fine in HP Tuners, but not the ECM (there are some exceptions but it's so rare it's best to just say, 'no').

[blindsquirrel]

If you don't need the VIN or anything else from the late E38 (like the higher injector limit), I guess the easiest solution would be to leave the TCM as-is and swap to an early E38, and problem solved. That's a combo that's readily available and not a frickin unicorn like the later combo.

[ssclone]

Thanks. I am not married to the vin as the set up is in a chevelle.
I could get an earlier ecu and see what happens. Is there any particular one before I make the same mistake. I?ll get pre 09.

Thanks.

[blindsquirrel]

12612384 is what the book says for '08 Express. You can buy one pre-flashed, give them the VIN from the Express van file.

[blindsquirrel]

UPDATE

Found a late-E38 127lb Express van file with 4L80E.

2009.5 Express 3500 6.0L 127lb E38 - T42 4L80E 24243356 1GBJG31KX91175952.hpt

You can write-entire the TCM only using that file. No guarantees, I am very curious if it'll communicate with the truck ECM/OS though.

[ssclone]

i was about to buy an 08ish ecu but i will give that a try in the next few days.

thanks

[ssclone]

UPDATE

Found a late-E38 127lb Express van file with 4L80E.

2009.5 Express 3500 6.0L 127lb E38 - T42 4L80E 24243356 1GBJG31KX91175952.hpt

You can write-entire the TCM only using that file. No guarantees, I am very curious if it'll communicate with the truck ECM/OS though.

just for s&g's i tried to do a vin change to the current vin i am licensed to and it said incompatible vin/os.

since my current tcu and ecu have the same vin on it for a 2013 truck, im going to have to license the file you found just so i can do a write of the tcu only, correct? i hate to spend the money on the license and it doesnt work and i still buy another ecu and have to license that also. when i bought the tcu i had it flashed to the vin of the ecu.

the car works fine currently, drives just fine. its been 11.7's with the current set up. i just dont have a mph read out, and that started back when i first did the swap and had a t56 in the car.

[blindsquirrel]

I *think* it would be 'free' if you could get a GM calibration flashed onto the existing TCM using dealer-type tools. HPT checks the file you're flashing for license, and the serial# of the module for license, but I don't think the VIN is stored anywhere in the TCM. I do know the VIN isn't used for ECM-TCM communication/security or anything like that. Flashing with a different file or swapping in a different pre-flashed TCM would both cost credit(s). (Unsure if it's one or two credits to swap in a spare, I have a pending question about that in another subforum that I suspect will go unanswered forever.)

This is where having your own Tech2/MDI/VCXnano/Mongoose and a TIS subscription comes in super handy. I would send you a spare TCM GM-flashed with the '09 file but I just checked that VIN, my dumb free offline TIS2000 doesn't go up that far. It has coverage for the '08 Express VIN, because of course it does. xD

[ssclone]

UPDATE!!

I bit the bullet and licensed the 09.5 express van file that blind squirrel had shared, did a rewrite on the ecu, loaded my previous parameters and the mph now works!

Now because of this I have to retune the ecu haha. Already had to take 50% out of the entire raf table just to get it to idle.

Looks like we are on the right track.

Thanks a lot


Aaron

[blindsquirrel]

screenshot.06-02-2019 19.53.32 numbered.png

Yeah, just so you know... you now have a mutant hybrid, an Express van file with the '13 Silverado throttle controls left behind in the two segments HPT can't/doesn't access.

It may work, or it may have issues that are unsolvable. Doing a full, correct write of the Express file with GM SPS will put in the correct hidden segments. If you reuse the current VIN it won't have to be relicensed again, as the VIN+serial won't change. Only do that though if you have weird bullshit mystery throttle problems, it may break compatibility with the existing throttle body/pedal.