Car system conformance testing

Electronic control systems in cars get more an more complex. Currently there more than 30 networked control units communication over networks even in medium sized cars. Apparently the communication link is a crucial factor for the proper function of the whole system. Although there are standardized communication protocols the interoperability of the communication modules may be questioned as the specification of the standards may be partially not strong enough as to ensure that different implementations are sufficiently interoperable. There are various ways to assure a proper function of the communication network: One is to perform sufficiently exhaustive conformance tests on each implementation. Another way may be to force tighter and more formal specifications of the standards. This paper discusses both ways. In details - for the example of CAN Low Speed Fault Tolerant Transceivers - an empiric/systematic process is shown how to derive sufficiently exhaustive tests. Furthermore the paper discusses how these empiric based processes can be enhanced by formal methods to derive better exhaustive tests and even how to enhance the quality of an existing specification of a component and thus from there to derive a further optimization of the verification tests.