| 摘要 |
A load drive circuit incorporated into an onboard electronic control device, the load drive circuit housing a diagnosis circuit for diagnosing load abnormalities, wherein diagnosis circuit malfunctions are detected without affecting load drive control. When a malfunction has occurred in the diagnosis circuit, vehicle operation is not affected because the diagnosis circuit does not have a function for controlling the vehicle, and there may be cases in which occupants riding in the vehicle do not notice the malfunction. Additionally, when a malfunction has occurred in the diagnosis circuit, the occurrence of the malfunction cannot be detected even by a vehicle control system as long as there is no function for detecting occurrences of malfunction in the diagnosis circuit. Specifically, when a malfunction has occurred in the diagnosis circuit, there is a possibility that the malfunction is unrecognizable to occupants and undetectable to a vehicle control system. When there is no need for the diagnosis circuit to diagnose load abnormalities, a determination of whether or not the diagnosis circuit is malfunctioning is made by sending a false abnormality signal to the diagnosis circuit and confirming whether the diagnosis circuit can detect the sent false abnormality signal as a malfunction. |
