This Preliminary Information communication provides information to the technician about vehicles that when a phone does not charge properly or charging cycles is on and off rapidly when connected to the single port USB hub of the vehicle. Technician should check the Human Machine Interface part number Dealer should communicate to the customer that we apologize for this inconvenience and that General Motors is working on a solution for this concern if the Human Machine Interface part number ends in 8433. Technician should follow published Service Information diagnostic if the Human Machine Interface part number is not 8433.