So very very wrong!
Please DON'T post misinformation if you're not sure of the facts.
JZ uses a 341 Trans it has PWM controlled line pressure and PWM controlled Converter lockup and another PWM solenoid for shift quality.
I run a 341 Valve body in my 340 due to the DBW Throttle I use (No Line Pressure Cable drive)
The ECT can only out put ON/OFF signals and NOT PWM, I use a SSv4 and it's the same ON/OFF as the stock ECT, How I get around this is to feed the ON/OFF to the MoTeC and it outputs the required PWM signal to make it all work.
There's an aftermarket trans controller that can now do PWM it's
made by PCS and will do it all.