The use of IGBT power modules in the automotive industry is becoming more and more common due to the increase in hybrid and all electric vehicles. But, unlike industrial applications the duty cycle or usage of such devices due to the environment or operating requirement is very random and not well defined. This makes predicting when the device will fail very difficult as the life of the device is dependent on its use and temperature environment. This paper describes work being done on a real time, on line prognostic algorithm which uses the operating history of the device to calculate and predict the time of failure of the device.