RomRaider

This looks very similar to the TB48 TCMs. There is a huge demand for getting the ability to tune the TCM. The factory TCM calibration is terrible.

It's a custom Unisia JECS MCU based on the Motorola MC68HC16 architecture with both internal ROM and an external 256KB flash chip. A successful dumpmem MAY even be as simple as knowing the right start and end address to dump. Unfortunately I don't have a heat gun and flux to put the flash chip back on the board of my bench TCM to try this but I will at some stage.

I figured this would be the best thread to ask. Since my truck TCM shifts at 6000-6100rpm and the 350z shifts at 6800-6900rpm, would purchasing the NERS kit and flashing the TCM as a 350z work or am I over simplifying it? (I have the engine modifications to make use of the power up there)

I don't think anyone knows yet, I doubt it will work because a lot of the torque converter info is in the ECM.

However what initiates first i.e.
TCM -> ECM -> TCM ,

or

ECM -> TCM -> ECM -> TCM


My Guess is its a reciprical conversation, but who starts it? I would assume the ECM starts the conversation with a torque request. ECM looks at all data and says we require XYZ to occur for this.
I.e, this gear, this rpm and this timing/throttle opening/valve train modification = XXXX torque. Therefore initiate the sequence.

I presume that conversation is married up with each engine/gearbox pair.

Just how we all have similar ecu types, whats on the ecu will be greatly different.

I believe the same will be for the TCM.

Thank you for the replay, that makes complete sense. I may have figured out a work around to get the OEM "paddle" shifters from another Nissan to work, not like I'll be spinning the motor to 7k every day on the way to work with these gas prices

After checking the MPC555 processor datasheet, I'm finally getting around to testing different memory areas. Atm, I'm dumping the SRAM A/B areas Nisprog can handle this just fine with $AC thankfully. So we now can datalog TCM SRAM parameters!

Any progress on this? I have a RE5R05A tcm from European market, part number 31000-EB70B wich I want to dump it to write it to an USA market tcm wich has some differences in calibration, i.e if I install an USA Market tcm in Pathfinders that I have here, sequential shifting stop working.

What vehicle is it?

It's a 07 Pathfinder R51

After spending quite a bit of time reverse engineering the TCM's software and getting a TCM for bench testing, I've finally cracked the security algorithm + reprogramming logic and have completed a full ROM flash! I created my own ROM Editor program beforehand, so I made a J2534 wrapper and added all the necessary communication protocol logic to flash the TCM there.

The only downside is that the bootloader is write protected, so the main utility is with modifying the current ROM software rather than flashing a different TCM variant.

It feels surreal going from not knowing if the TCM could even be reprogrammed to flashing it for the first time. It's funny how I started off my tuning adventures not wanting to have to learn to code at all, to now being able to understand SuperH and PowerPC assembly, as well as developing a fully-fledged ECU and TCM reprogramming program in C#

Next step for me is learning to speak transmission, so I'm going to be spending a lot of time taking datalogs and getting a better understanding of everything that's occurring. I'm really curious to see how much tuning the TCM can improve shifting performance, as tuning the ECU alone has worked extremely well.

There is some detail in here about overall transmission processes for the 5 speed - https://www.romraider.com/forum/viewtopic.php?f=40&t=13725&start=330

Rimwall describes some functions and also found a few location in the Subaru TCU's memory that control pressure to specific circuits in the transmission. The Subaru 5EAT is built off the same Jatco 5R05 as the RE5R0RA. I would be surprised if there wasn't similar control logic.

Thanks for the reference! The FSM has helped a lot as well with figuring out the functionality of each solenoid.