Patent ID: 8412412

Claim:
A vehicle communication system comprising: a plurality of electronic control units that is mounted to a vehicle and connected with each other to enable data transmission therebetween via a network; a master unit that is one of the plurality of electronic control units, and that is a master of the plurality of electronic control units; and a plurality of slave units that is the others of the plurality of electronic control units, wherein: the master unit is configured to distribute a vehicle common information element to the plurality of slave units via the network each time a preset condition for distributing the vehicle common information element is satisfied, the vehicle common information element including information to be commonly utilized in the plurality of electronic control units; each slave unit includes a common information storage medium configured to store the vehicle common information element distributed from the master unit, a memory abnormality determination section configured to determine whether an abnormality occurs in the common information storage medium, an initialization section configured to perform initialization of the common information storage medium when the memory abnormality determination section determines that the abnormality occurs in the common information storage medium, and a slave side vehicle common information transmission section configured to transmit the vehicle common information element stored in the common information storage medium of the each slave unit; the plurality of slave units comprises a group of slave units predefined as volatile memory slave units in each of which the common information storage medium is a volatile memory, which maintains data by being powered from a battery mounted to the vehicle; and the master unit is further configured to determine, in cases where (i) the master unit receives the common information elements from all of the volatile memory slave units, (ii) at least one of the received common information elements has an initialized initial value, which is a value to be set when the initialization is performed by the initialization section, and (iii) not all of the received common information elements has the initialized initial value, that an abnormality other than a battery detachment abnormality has occurred in the common information storage medium of the volatile memory slave unit in which the common information element has the initialized initial value, the battery detachment abnormality being caused by detachment and attachment of the battery.