Patent attributes
A comparator compares the total intake air amount accumulated by an accumulator with a reference value obtained via a selector. If the total intake air amount is smaller than the reference value, the CSS control is determined as being abnormal and a CSS-abnormality signal is output. If the number of times an atmospheric pressure learning value has been updated is equal to or larger than a threshold that is set large enough to determine that the accuracy of the calculated atmospheric pressure learning value is sufficiently high, a reference value is output from a characteristic storage to the comparator. Conversely, if the number of times the atmospheric pressure learning value has been updated is smaller than the threshold, an initial reference value is output from an initial reference value storage to the comparator.
