I just learned how you can turn off the Traction Control system on an RX 400h:
1. Switch the car off, then switch it on without (ready) light.
2. While on P, press the gas pedal 4 times.
3. Shift to N, press the gas pedal 4 times.
4. Shift to P again, press gas pedal 4 times.
5. Switch the car to ready and drive (at your own risk) without computer controlled wheels!
The next time you start the car it will be back to normal again.