Lexus Troubleshooting Questions? Ask a Lexus Expert
Based on your description it sounds like alternator belt has failed. Check the drive belts and see if possibly the alternator has failed taking out the drive belt. When this belt comes off it will cause all the warning lights to illuminate on the instrument panel especially if driven until the battery is dead. Make sure the battery is fully charged and see if the vehicle will start back up. Also it is common for these high miles for the water pump to fail which could cause the timing belt to jump time and this will cause the vehicle to quit running. If the engine is cranking over unusually fast this is a sign that it jumped time. Let me know how things go or if you need any other input on this matter. If you need a second opinion after visiting the repair facility feel free to reply with that information I can comment further.
This still sounds like the battery is dead do to the Alternator not charging. Did he look at the drive belts yet and try to jump start or charge the battery?