A vehicle communication system including a master ECU and multiple slave ECUs is disclosed. Each slave ECU initializes its storage medium if an abnormality occurs in the storage medium, and transmits a stored vehicle common information element. Some of the multiple slave ECUs are volatile memory slave ECUs in which the storage medium is a volatile memory. If the master ECU receives the common information elements from all of the volatile memory slave ECUs, and if at least one but not all of the received common information elements has an initialized initial value, the master ECU determines that a memory abnormality has occurred in the storage medium of the volatile memory slave ECU in which the common information element has the initialized initial value.