| 摘要 |
PROBLEM TO BE SOLVED: To detect an abnormality generation in a fuel system and to specify an abnormality site. SOLUTION: A transition state of a fuel pressure F/B(feed-back) correction value as a fuel pressure behavior when it is steppedly switched and varied at two different target fuel pressures and an air/fuel ratio F/B correction value as an air/fuel ratio behavior is detected. When the fuel pressure F/B correction value is within a predetermined range at Step S105, the air/fuel ratio F/B correction value is with in a predetermined range at Step S106 and a large behavior variation is not accompanied, it can be accurately judged that both fuel pressure sensor 27 and high pressure fuel pump 23 are normal. Whereas, when the air/fuel ratio F/B correction value is not within the predetermined range at Step S106 and the behavior variation is large, it is judged that a fuel system of the fuel pressure sensor 27 is abnormal and a fuel pressure F/B control is stopped. Thus, an abnormality site of the fuel system can be accurately specified by a simple judgment treatment.
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