What would happen if you drove the car w/o the steering ECU? The L-tuned ECU turns down the power steering so would removing the ECU turn off the power streering altogether? How would the car drive if this happened? Anybody care to try?

 

would you like to try?
j/k, sounds pretty scary man. I had experience with my old 92' Cadillac, the engine shuts down in the middle of my left turn, and power steering turned off immediately. WOW it was horrible, I had to hang on to the steering wheel and literally lean my whole body to get that wheel moving. NOT something you would want to experience.

 

Depends how the power steering has been designed. The power steering pump is still being driven by the drive belt. Toyota (Lexus) may have designed a safety feature so that if the ECU fails then full assistance is given all of the time instead of it being reduced at speed.

If assistance is fully removed then the car is too heavy and tyres too wide - it would be very difficult to park. In the UK a lot of cars do not have power steering and even something small like a VW Golf is very hard work without power steering.

I'm sure you would get a warning light on the dashboard if you remove the ECU.