Patent ID: 7685383

Claim:
A method of backing up vehicular data in a vehicular system that includes an engine electronic control unit for controlling an engine and a plurality of electronic units including a data storing function, each of the electronic units being arranged so as to be separated from the engine electronic control unit, with the vehicular system being configured such that data can be transmitted and received between the engine electronic control unit and the electronic units via a vehicular communication network, the method comprising: recognizing with a flag, in the engine electronic control unit, a first time the engine electronic control unit is installed; storing the most recent content of accumulated data including an engine running time data and a running history data in the engine electronic control unit and as backup data in the electronic units via the vehicular communication network at an appropriate time; transferring, when the engine electronic control unit is replaced, the backup data via the vehicular communication network to a replaced engine electronic control unit from any of the electronic units with reference to the flag provided in the replaced engine electronic unit; and initializing the replaced engine electronic unit with the backup data transferred via the vehicular communication network.