Missing step from most instructions posted. This is from Lexus TSIB dated April 10, 1998. Without this step my car would not enter the programing mode.
A. Before starting the programming procedures, make sure to SET UP the vehicle as follows.
1. Remove Key from ignition
2. CLOSE AND LOCK ALL THE DOORS (this is the missing step)
3. Manually unlock and open the driver's door only
Also, the instructions say to use the power door lock/unlock switch for cycling the locks. Maybe manually lock/unlock will work but mine entered programing mode using electric lock/unlock.