| 摘要 |
The present invention relates to an apparatus for diagnosing the presence or absence of a wire disconnection in a fuel injector drive circuit. When driving the solenoid of a fuel injector via a transistor by a drive pulse signal, the counter electromotive voltage used to turn off the transistor during a fall of a drive pulse signal is taken out and is charged to a capacitor included in the charge/discharge circuit. Also, the terminal voltage of the capacitor is determined during the rise of the drive pulse signal, and a wire disconnection is detected when the voltage is lower than a predetermined value. Further, a discharge of capacitor is started immediately after this determination, and a discharge of the capacitor is ended upon the fall of the drive pulse signal.
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