Overloading during the USB test

Fig 1: USB Test Output Voltage Graph

Courtesy of BMW OF NORTH AMERICA, INC.

The vehicle is not able to deliver the required level of current. The voltage (1) collapses and the current is thus limited.

Troubleshooting:

The customer may have attached a USB hub (distributor) to the vehicle USB connection. Always run the USB test directly on the USB connection in the vehicle!
Check the USB connection.
Check lines and plug connections in vehicle.
Check control unit.

NOTE: If the test was not successful, a vehicle diagnosis must be carried out with ISTA!