After 72hrs straight, on about 10hrs sleep, I was finally able to isolate all the ID's this T87 gasser version requires NOT set a U0100 code. Admittedly, I may have slightly under estimated the CANbus requirements a few pages back...
At least 8 ID's, each with 5 or more parameters, must be created out of thin air to bring it out of limp mode and clear the code. Some are easy, just a single bit switch, or rpm and min/max torque values that can be found in existing ECM transmitted parameters. Then some others, take a lot of thought. Calculated values based off multiple inputs like MAP, Load, MAF, APPS, and who knows what else. Engine ON or Off timers, and my personal favorites, 2-4 bit rolling counters.. And can't forget, the OS set axle ratio is also being sent to the TCM, for some speed comparison.. That wasn't the case prior to 15.. So I'm just now discovering all these new parameters used by the E92/94 models.
Luckily some of these "required" ID's will accept random garbage to fool the DTC triggers. Which actually helped to sort out what's critical and what's not. Yey some others like these counters, need to actually be rolling before TCM will accept the related data. And I haven't even checked the data heading back to the TCM from the ECM side yet. Hopefully the LMM to T87 Allison will have better matching parameter set. While we can probably write out some of these parameters in the TCM, it's hard to guestimate which ones are actually required to not screw up related tables.. TCM is requires specific engine torque related data to adjust pressures and shift times, and it also send out commands to defuel on shifts. So is gonna require a couple trees in paper to print all this out to visualize.
For now, I'm staying focused on sorting data, but I did receive this little piece of the puzzle today. Let ya know if it does the Trick..
