Hi Baz, I have the exact same problem as your original post with my 99 LS400. The fob won't open the car after the car has cooled down. If I go for a drive I can open and close with the remote over and over again. If I leave the car for an hour or more it won't, although sometimes if I keep trying for a few minutes moving the fob around the car it might work.
I changed the fob battery a few months ago, before this problem arose. I did have to trickle charge the car battery when we had that cold spell last month, but the car starts very easily now. Was your solution to change the fob battery and has that rectified it permanently?
Thanks,
John
