Self-diagnosis apparatus for vehicle

摘要

A self-diagnosis apparatus for vehicle capable of storing sufficient data useful for abnormality diagnosis includes a control unit having a CPU and RAM which can hold its stored contents even at the time of cut-off of an ignition key. The CPU receives diagnosis data necessary for analysis of the abnormality of an equipment at each predetermined period and judges whether or not the value of the diagnosis data exists in a predetermined region, in order to count up a counter of a predetermined storage region beforehand provided in the RAM corresponding to the judged region. The counting-up is stopped when the abnormality of an equipment is detected. In contrast with a method in which the value of diagnosis data is stored into the RAM as it is, the range of change of a lot of diagnosis data until the generation of abnormality can be stored with a small memory size.