Excellent post. Same issue on my 2008 GS350. Took it to Lexus and they told me it would cost over $1600 to fix. Found your post, opened the trunk to disconnect the cable to the ECU. It would require some dissasembly. Leaving the trunk open, I disconnected the main battery ground and waited 5 minutes and reconnected the ground. This also reset the ECU. I closed the trunk and now everything works fine again.
2007 Gs 350 Trunk Won't Open
in 06 - 12 Lexus GS300 / GS350 / GS460
Posted
Where do I find my ECU?