Anomaly diagnosis system

An anomaly diagnosis system to perform an anomaly diagnosis in an in-vehicle network where a plurality of electronic control units are connected to mutually communicate,

• the anomaly diagnosis system comprising:
• a power supply portion to provide an electric power to each of the plurality of electronic control units;
• a voltage detection portion provided in a subject electronic control unit being any one of the plurality of electronic control units, the voltage detection portion detecting a power supply voltage in the subject electronic control unit repeatedly while the subject electronic control unit perform an operation;
• an integration section provided in the subject electronic control unit, the integration section
• calculating a variation value indicating a variation that arises when the power supply voltage detected by the voltage detection portion is changed from the power supply voltage detected at a previous time, and
• integrating the variation values calculated repeatedly to calculate an integrated value with respect to the subject electronic control unit;
• and
• a diagnosis section to perform an anomaly diagnosis based on the respective integrated values calculated with respect to the plurality of electronic control units,
• wherein:
• the integration section calculates the integrated value by substituting a corresponding value for the variation value at an activation time when the subject electronic control unit is activated, the corresponding value corresponding to the power supply voltage detected by the voltage detection portion at the activation time when the subject electronic control unit is activated;
• and
• the diagnosis section performs the anomaly diagnosis using only the integrated values each being greater than zero.