| 摘要 |
<p>PROBLEM TO BE SOLVED: To diagnose a backup RAM system by highly precisely discriminating the abnormality of this backup RAM due to battery exchange or the like, and the substantial abnormality of the backup RAM system. SOLUTION: A processing for detecting the failure of a backup RAM is operated (S1). When any abnormality is detected, this process is advanced to S3, and when normality is detected, this process is advanced to S4. A failure counter value is incremented A times in S3, and the failure counter value is decremented B times in S4. Then, when the failure counter value >= a prescribed value C in S5, it is diagnosed that any failure is present in a backup RAM system in S6, and a driver or the like is allowed to recognize it in S7. On the other hand, when the failure counter value < the prescribed value C, it is diagnosed that temporary abnormality due to battery exchange or the like is present, and this main flow is ended as it is. Thus, abnormality due to battery exchange or the like and the substantial abnormality of the backup RAM system can be highly precisely discriminated so that this backup RAM system can be diagnosed.</p> |
