Method for detecting abnormality in the functioning of an electronic

Abstract

A method for detecting an abnormality in the functioning of an electronic control system of the type including at least one input means, and at least one output means, wherein the input means is operable to detect the value of a parameter determining the operation of the output means and generate a signal indicative of the detected parameter value, on the basis of which the operation of the output means is controlled. First, a determination is made as to whether or not a predetermined condition exists wherein determination of the above abnormality can be effected. When the predetermined abnormality detection-permitting condition exists, it is determined whether or not the above detected parameter signal value from the input means or an operating amount signal indicative of the operation of the output means has a value satisfying a predetermined condition of normal operation. When the detected parameter signal value is determined not to show a value satisfying the above predetermined condition of normal operation, the time elapsing from the determination of dissatisfaction of the same condition is counted. When satisfaction of the predetermined condition of normal operation is determined before the counted elapsed time value reaches a predetermined value, the counting is interrupted. When the counted elapsing time value reaches the predetermined value, it is diagnosed that an abnormality exists in the functioning of the above corresponding input means or output means. When a predetermined abnormality detection-prohibiting condition exists after the counting of the elapsed time has been started and before the counted elapsed time value reaches the above predetermined value, the counting is also interrupted. The present abnormality detecting method can advantageously be applied to an electronic control system for internal combustion engines.