US Patent 7826962 Electronic control apparatus

The electronic control apparatus includes a microcomputer having a control function of controlling an actuator mounted on a vehicle in accordance with an input signal indicative of a running state of the vehicle, and a self-monitoring function of monitoring whether or not the control function is functioning properly on the basis of the input signal, and a monitor module communicably connected to the microcomputer and having a digital circuit for monitoring whether or not the self-monitoring function is functioning properly. The monitor module includes a reference counter counting up a clock serving as operation reference of the digital circuit. The microcomputer includes a module monitoring section configured to take in a count value of the reference counter and to monitor whether or not the monitor module is functioning properly on the basis of a changing state of the count value taken in.