Onboard diagnosis of electronics, a contribution to vehicle reliability

New semiconductor technologies have led to a continuous increase of automotive electronics, that the service shops must cope with, today and above all in the next years. As a tool for exact fault localization in the car, the onboard diagnosis was introduced in BMW automobiles. Via a two link wire all electronic control units containing a microcomputer are connected to each other and can be questioned systematically for faults by the test equipment. The concept of the data exchange is so, that the information can be transmitted not only with fixed but also with variable baudrates. Therefore, the onboard diagnosis gives an important distribution for a complete integrated service concept.