A torque-generating system includes one or more torque-generating devices, a transmission having an output member, and a controller. The controller executes a method to control an operation of the system when the output member is operating at zero output speed. The controller is programmed to determine a torque request level and an actual speed of the output member, and an effective speed of the output member, as a calibrated non-zero value, using the torque request level when the determined actual speed is zero. The controller calculates an effective power of the powertrain using the effective speed and torque request level. A control action is executed with respect to the powertrain using the calculated effective power, including transmitting powertrain control signals to the torque-generating device(s) to select an appropriate powertrain operating mode.