GM Repair Problems? Ask GM Repair Expert Now.
I am sorry you are having this problem
if the alternator is showing it is charging at idle then the belt should not have come off
usually with reduced power lights on it means there is a problem with the electronic throttle system which can be a connection at the gas pedal or throttle body
if you shut it off and start it back up and that message is still displayed in the dash have it towed to the dealer for them to pull the codes to find out which the problem is turning on the message in the dash as usually it will run in reduced power mode and be just about un drivable