[b3lha]

I've done some investigating, tracing the wires on my JDM 94. It turns out I was wrong. The TCUs are not the same, but they are extremely similar and I haven't given up on the idea of them being interchangeable.

The TCU wiring is exactly the same as your Aussie diagram except:

Pin a4 is connected to the "power mode" button rather than the "economy mode " button. In both cases, the switch connects the pin to ground to activate the mode. Since the same pin is used for "power" on JDM and "econ" on Aussie cars, the TCUs must be different, but I think it is just a firmware difference rather than hardware.

a17 and c6 are not connected. This is the circuit that I believe converts the inductive speed signal into the square wave signal. The pins are connected to the circuit board internally so I think the conversion circuit exists in the JDM TCU, but is not used.

In conclusion, I reckon:

Aussie and JDM TCUs are the same except for the firmware. A JDM TCU can drive an Aussie gearbox and vice-versa provided that you wire the speed sensors appropriately.

If you put a JDM TCU in an Aussie car then the Econ button (if you have one) will operate power mode. Similarly if you put an Aussie TCU in a JDM car then the power button will operate Econ mode. In both cases you would have to adjust the wiring slightly to get the dash lights to show the correct mode.

Interestingly, the wiring schema is practically identical on USA models too, which makes me wonder if their TCU is also the same except for the firmware. Presumably their firmware would be significantly different and not interchangeable with ours. However, I wonder what shift mode pin a4 would activate on an american TCU? I think I'll start another thread to discuss that one.