Abstract: An electromechanical motor vehicle power steering mechanism for assisting steering of a motor vehicle including an electric motor for steering assist and a torque sensor. The electric motor is configured to apply an assistance torque in response to an output signal from the torque sensor indicative of the input torque applied by a driver of the vehicle to a steering wheel, in which the relationship between the indicated input torque and the assistance torque applied by the motor is defined by a boost curve. A logical summer is used to restrict the relationship between the indicated input torque and the assistance torque within given safety limits.