A brake rotor temperature determination or estimation system and method for controlling output power of a power source in a vehicle. The system includes a brake rotor, a processor, a memory, a speed sensor and a temperature sensor. The speed sensor senses a speed of the vehicle. The temperature sensor senses a temperature of a brake rotor or ambient air in a vicinity of the brake rotor. Based upon data stored in the memory and inputs from the speed sensor or the temperature sensor, the processor determines if an output power of the power source should be limited based on rotor temperature thresholds. The power limits may be defined as discrete power limits corresponding to the particular thresholds of rotor temperature or may be defined as interpolated data values along a linear or nonlinear ramp or slope.