To supervise a program controlled device which is subject to stray noise or disturbance pulses, particularly microprocessor controlled automotive vehicle electronic systems, a timing circuit is provided responsive to check pulses added to the program and defining a timing interval, the monitoring system distinguishing between disturbance pulses and static defects by supervising the control pulses and, upon failure of the control pulses, generating a program restart or interrupt signal, respectively, which both initiate a new start of the program cycle or, respectively, define a timing interval which, upon failure to sense further control pulses, initiates energization of an emergency switching system. Continuous failure to receive control pulses also can initiate the emergency switching system. To permit start-up, and before control pulses are obtained, a time delay circuit is provided which disables the monitoring system upon switching ON of the program controlled device at least for the time period of one check pulse cycle.