Hi Lexus Genius's, I know this is an old thread, I need help with the same issue on my SC430, I've been searching ECU's online and the only one I can find which may control the fuel filler door/trunk maybe the Switch, Door Control ECU, part number 84931B 8493124030
Anyone know where the ECU is located on the car, I'm guessing under the dash some where and would this cure the problem?