You can substitute a 5 cent 1/4 watt resistor....
Check the shop/repair manual for the range of resistance for the leveling sensor and pick something in the middle to start. Then adjust the resistance empirically, trial and error, until the auto-leveling sequence settles at about the right, desired, height.
Hopefully you can help me. I have a 05 LS 430 with the same problem. The light will flash for minutes and then just go away. My guess is the problem is getting worse and the flashing light happens more frequently. Can anyone help to diagnose what the problem might be and if it is a module can I use a replaceemnt from any other lexus that has AFS?