Fault deciding system for idle revolution controlling unit

摘要

When fully closed throttle opening learning device M1 learns a fully closed throttle opening value THMIN on the basis of an actual throttle opening value TH at an idle running time, comparison device M2 compares the sum of the fully closed throttle opening value THMIN and a predetermined value a with the actual throttle opening value TH to decide the possibility of the occurrence of a fault, and fault decision acceptance device M3 decides the acceptance/rejection of execution of the fault decision of an idle revolution controlling unit IC on the basis of the comparison result of the comparison device M2. As a result, even with a degradation in the output characteristics of a throttle opening sensor, an erroneous decision can be avoided by rejecting the execution of the fault decision when there is a possibility of an erroneous decision.