A transmission utilizes an electro-magnetically actuated selectable one-way-clutch. The one-way-clutch prevents rotation of a transmission member in both directions when a current exceeds a threshold and permits rotation in only one direction otherwise. To prevent un-intended engagement, a switch interrupts the current unless a second current exceeds a threshold. In order to engage the one-way-clutch, both currents are set above their respective thresholds by a controller. In the event of a single fault such as a short circuit, the system continues to function normally. The controller may periodically test for a fault by intentionally setting one current above its threshold and the other below its threshold and determining the state of the one-way-clutch by measuring speeds of transmission elements.