| 摘要 |
<p>PURPOSE:To provide a diagnostic device for automobiles for flexibly dealing with various kinds of abnormality occurring in a vehicle without considerably changing/adding hardware and for easily specifying causes, positions, etc., of the occurrence of abnormality. CONSTITUTION:A microcomputer 12 is a microcomputer for self-diagnosis, inputs the respective states of the vehicle inputted to an electronic control unit(ECU) 10 through a microcomputer 11 for vehicle control and performs the self-diagnosis of the vehicle by using a self-diagnostic program in a backup RAM 12d. On the other hand, the self-diagnostic program can be changed and added through a communication path 30 and a mutual communication circuit 13 by connecting an external diagnostic device (checker) to the ECU 10. The diagnosed result is stored and held in the backup RAM 12d and can be displayed by connecting the checker. In this case, the self-diagnostic program is provided with data showing the execution cycle of the program and the necessity of execution, and the self-diagnostic program is executed only when the data are normal.</p> |
