FAULT DIAGNOSIS DEVICE

摘要

Each time a power supply is turned on, an ECM (12-18) conducts fault diagnosis of another ECM, and writes fault information indicating a fault detected by the diagnosis into a fault information table created in a memory (123-183). The fault information is stored irrespective of turning on/shutting off of the power supply. Further, the ECM (12-18) receives an update halt request issued by an external PC (36) after the writing process of the fault information, and restores the fault information table (TBL) to the state prior to the writing process of the fault information. The fault information described in the restored fault information table (TBL) is sent to the external PC (36) in response to a fault information request issued thereafter.