A method for validating engine and motor velocities in a vehicle having an
engine and two motors is provided. The method validates the velocities
without using two speed sensors for each device. The velocities of the
engine and the two motors are first determined, and then mathematically
combined using known velocity relationships based on the vehicle
architecture. The mathematical combination of the velocities is then
compared to a first pre-determined speed range, and if the mathematical
combination is within the predetermined range, the velocities of the
engine and the two motors are validated. If the validation of the engine
and the two motors fails, additional equations can be used utilizing
additional inputs, including the vehicle speed as measured at the vehicle
wheels. In this way, the velocities of one or more of the torque
generating devices in the vehicle may be validated.