OK, well I do appreciate the help but the scenario may be a bit different than you are thinking.

This is a custom vehicle, so the only thing Lexus in it is the AA80E. I have built and installed one very special MegaShift transmission controller, currently the only one of it's kind athough a Celica builder has also been working on one. I haven't heard from him in awhile. So I am ready to fire it up and do some testing but I'm tidying up loose ends in an attempt to catch any "gotcha"s before they get me.

I have the solenoid chart that gives on/off states in the various gears, none of which show all solenoids off or de-energized. Yet actual testing demonstrates that the transmission will move the vehicle in both the R and D shifter positions even if it has none of the electrical connectors plugged in. I was attempting to reconcile this chart with unpowered limp mode. This requires some missing information, which so far has been unavailable to me.

Theory: Possibly the hydraulic circuits read all solenoids de-energized and shifter in Drive as a condition to energize Clutches 1 and 4. I don't know what it would take to do this but have to assume at this point that it is possible and is likely to be what the tranny is doing.

Looks like from this point on it will be a fair amount of guesswork, but the biggest part of the job is done.

Jim