| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem that it is difficult to diagnose the presence/absence of a fixed-closure abnormality of a power supply relay when using a power supply circuit having a pre-charge path for pre-charging a capacitor connected between an H-bridge circuit and the ground, and an electric path between the power supply relay and the ground. <P>SOLUTION: In an abnormality diagnosis device, a power supply relay 40 is opened by turning off a switching element 60 after an ignition switch 50 is turned on to be opened. If the power supply relay 40 has no fixed-closure abnormality, a charge voltage VPc of a capacitor 42 is lowered. On the other hand, if the power supply relay 40 has the fixed-closure abnormality, the charge voltage of the capacitor 42 is not lowered. A microcomputer 30 diagnoses the power supply relay 40 with respect to the fixed-closure abnormality based on the charge voltage of the capacitor. <P>COPYRIGHT: (C)2010,JPO&INPIT |
