The former owner replaced the battery in 12/30/10, one month before trading the RX in. The battery probably just died out. The service records did not indicate a reset. Lexus went throught the certification inspection at trade in. The former owner stuck to the Lexus maintenance schedule from day one; never mentioning in the service records with milage issues. As a side effect from this, also replaced maintenace parts with Lexus recommended parts ie battery, Goodyear tires, brake linings etc.
After I picked up the RX after the reset, I immediately noticed being in battery mode at low speeds and a combo there after, something I was not able to duplicate previously. The updated maintenace log on My Lexus indicates "ISC reset per customer request".