| 摘要 |
PURPOSE:To raise the accuracy of a trouble diagnosis by comparing an output value from a detector for detecting a prescribed operating condition of an internal-combustion engine with a normal output region under a special operating condition. CONSTITUTION:An arithmetic circuit 4 reads the number N of engine revolution from a rotary sensor 2, decides whether N=0 or not (S1), and does not make a trouble diagnosis when Nnot equal to . On the other hand, the arithmetic circuit reads any output from an AD converter 3 at N=0 to decide (S2, S3) whether an intake air flow rate signal Q from an air flow meter 1 is within the set region or not, and outputs (S4) a specific bit ''1'' of a memory 5 when said flow rate is outside the set region to alarm the troubles of the air flow meter 1 via an alarm device connected to the memory 5. It is possible in such a way to raise trouble diagnosis accuracy. |
