| 摘要 |
<P>PROBLEM TO BE SOLVED: To keep the executing frequency of malfunction diagnosis of components and systems mounted on a vehicle at a required level or higher. <P>SOLUTION: An ECU 28 executes the deterioration diagnosis of a catalyst 23 the leakage diagnosis of an evaporating gas purge system 37, the malfunction diagnosis of an EGR system 29 and the malfunction diagnosis of a secondary air introducing system 32. In this case, the executing frequency of each malfunction diagnosis is calculated, and when the executing frequency is satisfied with the required level, the malfunction diagnosis is executed in normal conditions of the malfunction diagnosis (execution, diagnosis and determination) giving no poor effects on exhaust emission and drivability. On the other hand, when the executing frequency of the malfunction diagnosis is not satisfied with the required level, the malfunction diagnosis is executed in different conditions of the malfunction diagnosis, stressed on increased executing frequency of the malfunction diagnosis, thus producing the increased executing frequency of the malfunction diagnosis. <P>COPYRIGHT: (C)2003,JPO |
