ISOLATION FAULT DETECTION ON DC CHARGE BUS

A vehicle power system includes at least one main switch to electrically connect a traction battery and electric machine, at least one DC charge switch to electrically connect the traction battery and a DC charge port when the at least one main switch is closed, and a controller to, while the DC charge port is disconnected from a DC power source, sequentially close the at least one DC charge switch and then the at least one main switch.