PURPOSE: To improve the accuracy in finding troubles by memorizing any troubles occurring during the diagnosis period.
CONSTITUTION: In connecting the fault diagnosing device, the connector terminals 30a, 20a on the wire harness side and the control circuit side are disconnected and a diagnosis circuit 70 is connected thereto. The circuit 70 comprises level determination diagnosis circuits 71 to 74, a logical determination diagnosis circuit 75, and a current determination diagnosis circuit 79. When a determination circuit 71A determines an abnormal condition, a counter drive circuit 71D connected to the circuit 71A drives an electromagnetic counter 71E once per one abnormal condition, and the number of the drives is memorized. This example is of an electronic fuel injector. However, this system can be applied to other devices. The number of occurrences of abnormal conditions thus memorized is compared with a reference level by a comparator for diagnosis, thus various kinds of diagnosis can be performed.
KOBAYASHI NOBUYUKI
WATANABE HARUO
KAWAI MITSUO
TOYOTA MOTOR CO LTD