pcmhacking.net

Ok. So we have a compatible E40 ECM (05-06 GM LS Gen IV) to T43 (6L45-90) basic "drive" solution. However, we have a tag-along problem that we didn't anticipate, the PRNDL. Apparently, gear selection signal codes are drastically different and inherently programmed into the CANbus communication (i.e. ignores usual IMS and PNP signals). Sooo, anyone out there who can either suggest a solution or personally do some core rewrite of the T43 calibration to align the T42 IMS signal to the expected T42 PNP signal?

probably need someone clever enough with ghidra to decompile the relevant t43 & t42 os/cals to work it out.

i'd be keen to hear more, i've got a a 6l80e/e40 combo in a mates car via pcs controller acting as the middle man. Was originally a manual though so dont need to worry about the t42.

did u end up getting this solved, what is your actual problem? Is it just the PRNDL not being indicated correctly?

I will probably be tackling this problem on the car i mentioned previously as I think i have the can stuff understood & covered now.

I know from previous email convo u got this working via the factory os.

but since i got the e38/t42 to t43 worked out, I'll have a customers e40/t43 combo coming in to work out in the next week.

Will post back with how i go.

Tre-Cool wrote: ↑Tue Feb 11, 2025 10:37 pm I know from previous email convo u got this working via the factory os.

but since i got the e38/t42 to t43 worked out, I'll have a customers e40/t43 combo coming in to work out in the next week.

Will post back with how i go.

Did you ever get this working?

car got delivered yesterday.

i need to modify the harness, with the current workload. probably be a few weeks before i get into it.

I am in awe of that perfect timing. Nearly 2 years later and the thread picks up within a day of vehicle delivery!

ironically 2 years ago, i hadn't delved into the e40/e38/t42/t43 code as much as i have in the last 8 months.

After getting the vz e38 working, i started looking into the e40 code and while it's a different cpu type, the code function structure is very similar when you compare the 2 in ghidra.

i just started from known options & followed along.

new harness is 80% in.

just need to run it into cab and connect to ecu. then flash tune in and see if it at least starts.

so small update. new harness is on. modified trans tune to show up gear shift positions correctly. flashed update to ecu with new cal settings.

ecu no longer responds to programming or scanning, but it still transmits on the can. no idea wtf has gone wrong there. so have cracked the case open to bdm it back to an old bin file.

when i get it back flashing via can, im going to flash the same file back in and see if it happens again. if it does, process of elimination to find out why.

it's like ive turned on a "do not respond to can tool messages" feature...

I even double checked all the addresses & code structure in ghidra compared to e38 and everything looks to make sense. I suspect I will need to change the tcm to an older pre 2009 model still.