This past weekend, my '07 GS450h with 16k miles lost power at expressway speed. "Check hybrid system" "Check ECB" and "Check VSC" all flashed in the monitor in between the speedo and the KWh power gauge. I pulled over and noticed that the hybrid battery had also drained to the minimum level (purple bars). Had Lexus roadside assistance tow the car to the nearest Lexus dealer. Before the tow truck arrived I decided to hit the start button again to see what happened, and to my surprise, everything seemed fine - no warning messages and car accelerated just fine. I drove it for a few miles but had it towed to the dealer anyway. A little concerned as the car has been unbelievable thus far, no complaints. Hoping this is a complete fluke and not a chink in the whole hybrid technology. Anyone have a similar problem or ahve heard of this?

This type of thing occurs in non-hybrid vehicles when one of a few things happen.
1. The battery is weak or is damaged internally. A circuit board that is failing can produce similar symptoms.
2. A chassis ground wire is loose.
3. There is a short somewhere.

I would think that one or more of these causes could show up in a hybrid as well, although the majority of Lexus and Toyota hybrids have had stellar reliability.

Oh boy, i hope everything gets fixed! I often wonder what other hybrid problems we'll face :/