MALFUNCTION DIAGNOSIS SYSTEM AND METHOD FOR ON-VEHICLE ELECTRONIC CONTROL UNITS

摘要

A diagnosis system for diagnosing malfunctions of on-vehicle electronic control units (ECU) includes a plurality of ECUs and a diagnostic tester. The ECUs are connected to one another, thereby forming a communications network. The ECUs store a data related to malfunctions. A diagnostic tester is connected to an engine ECU for reading the data stored in the ECUs. The tester transmits an initialization signal at a low speed to the ECU when starting communicating with one of the ECUs. The ECU selects a transmission rate between the ECU and the tester based on the initialization signal.