A question;
If it was 'just' the signal from the wheel sensor causing an out of expectation with the programming parameter/algorithm (and then a resulting malfunction), couldn't a micro controller be used to intercept the wheel sensor signal, process it by the 1.1(example of a ratio change), then outputting the original sensor signal by the 1.1(still only an example) changing the signal going to the ECU TCU? Fixing the issue?

Or am I missing something?

I cannot see why that would not work, except it would throw out the OBD speed measurement. I'm not sure the wheel sensors are linked directly to the TCU. In fact, I'm not sure where they are physically wired to. The primary function of the wheel sensors is for the ABS, so I would expect them to be connected to this system. The TCU could be getting it's data via the bus system.

I should see about buying one of the new DRB-3 micro-pods. They are down to a couple of hundred now for the knock-offs. I have read that you can set the diff ratio via DRB-3. If so, it is much less "fun" but a far simpler solution.

BTW - Just because I know how to dismantle, solder and reassemble the TCU, don't assume I know how to hack one. I have not tried, but I am not confident I could. There are often several layers of protection programmed into these devices.

I'm thinking you could definitely use a few cheap MC's at a few of the points mentioned to trick the system where needed. Including the dashboard speedo display. But it seems no one is doing that simple trick.

Haha. When you say you could hack the ecu tcu directly I'm sure you could. But it comes down to having the time to get into it. That's the issue hey. Not enough time in the day.

I queried about reverse engineering the machine code of the ec and tc units in the Pirate4x4 thread i started. And yeah, i have not the gear to go anywhere near it. Eg... eliminating wire tapping data echo electronically if you were going to log every wire in and out of the ecu tcu...

It'd be good to set time aside to get into it. I find it extremely alluring. Puzzle solving at it's best

Thinking about my last post, 1st paragraph...

You'd just nedd one MC, like the Arduino mega 2560. With wires going to and from the different sensors and units...to the different pins on the Arduino.

Plenty enough pins in and out on the one MC. Don't need a few.

I'll be keeping an eye on this/related posts. I'm currently studying mechatronics engineering and getting quite involved with Arduino's atm. I've sold my 2.7 CRD, but I've got a couple of 4.7HO now to play with when I've got time

Excellent. Your input will be valuable.
Looking forward to what you find out

I'm also keeping an eye on this thread. Simply becoz I know fart all about what youse lot are talking about!! :D
Sounds like some Terminator 4 shit..I'm so bloody confused! Lol!