The invention relates to a method and an apparatus to monitor an output speed sensor during operation of an electromechanical transmission. There is provided a method to monitor a sensing system adapted to monitor an output of an electro-mechanical transmission. This includes monitoring rotational speed of a wheel operatively connected to a driveline operatively connected to the output of the electro-mechanical transmission. A first expected output of the transmission is determined based upon the output of the first sensor. A second expected output of the transmission is determined based upon a rotational speed of a torque-generative device operatively connected to the transmission. The first and second expected outputs and an output of the sensing system adapted to monitor the output of the electro-mechanical transmission are compared.