The present invention provides an automotive control unit and an automotive control system. An object of the present invention is to enhance the accuracy and the level of detail of an abnormality diagnosis by checking a transmitting-end application or controller for an abnormality by using abnormality diagnosis results concerning a plurality of communication messages. The automotive control unit has a plurality of applications for controlling a vehicle-mounted device and a common execution environment section for permitting the applications to exchange data with each other. The automotive control unit includes a communication protection section that, when the applications exchange data with the common execution environment section, checks the data for an abnormality, and a system abnormality check section that determines in accordance with an abnormality check result produced by the communication protection section whether the system is abnormal.