Are you looking to hear if this fixes the issue? If so, I can tell you it did for me. I had the typical hard downshift from second to first, it was really hard shift, and I had it repaired by them. It fixed my issue without have to reflash the software or anything like that. Now, I did send in my original ECM so my VIN info was already on the computer. I've heard if you buy a different ECM you'll have to have it updated with your car specific information.

 

@rrgone and any others who are interested: I received my ECM back from SIA Electronics today and installed it back into my LS430. The car was previously undriveable with the failing ECM/hard-downshift problem, and now it's working perfectly. They did the work for a VERY fair price and offer a lifetime warranty on the repair. So for anyone who asks, count me as one more enthusiastic recommendation.

THANKS VERY MUCH to all the others who illuminated this problem in various threads over the years! I learned a lot and for less than $150, got a problem fixed that would have cost me $1500 minimum at the dealer (for a new ECM) -- and potentially MUCH more if I'd been led down the "transmission-trouble" misdiagnosis rabbit hole. BRAVO to this site!!