A method of operating a torque converter clutch in an engine start-stop vehicle improves launch after an auto stop event. During the autostop event, hydraulic fluid is supplied to the torque converter clutch operator through one or more solenoid valves by an auxiliary electric pump. When the prime mover is started at the conclusion of the autostop event, the torque converter clutch is thus locked, assuring rapid and sufficient torque transfer through the torque converter to the transmission and improved acceleration during vehicle launch. As the vehicle accelerates, the hydraulic pressure in the clutch operator is reduced and slip through the clutch increased to achieve a smooth launch and return to conventional torque converter operation.