An automotive accessory drive system for a motor vehicle connects to an internal combustion engine crankshaft during at least one mode of operation. The system includes an accessory drive pulley, a starter motor/generator, and an endless loop power transmission member connecting at least the starter motor/generator and the accessory drive pulley. A planetary gear set includes a sun gear, a ring gear integrally associated with the accessory drive pulley, and a planetary carrier connected to the engine crankshaft. First and second one way clutches connect the engine crankshaft to the ring gear, and the sun gear to a grounding member, respectively, to define a normal drive mode and an engine start mode, respectively. An electromagnetic disconnect includes a normally closed friction clutch connecting the grounding member to ground to define a third mode of operation corresponding to a free wheel function with the grounding member disengaged from connection to ground.