Electronic control device and method for diagnosing electronic control device

An electronic control device comprising:

• a power supply IC;
• a microcomputer to which a power supply voltage is supplied from the power supply IC;
• an excitation amplifier that excites a resolver;
• and
• a diagnostic circuit that monitors an input signal and an output signal of the excitation amplifier and diagnoses abnormality, wherein
• the diagnostic circuit compares the input signal with the output signal to perform abnormality diagnosis of the excitation amplifier, and transmits a diagnosis result to the microcomputer, wherein
• the microcomputer transmits a diagnosis input signal to the excitation amplifier after system power is turned on;
• the excitation amplifier outputs a diagnosis excitation signal based on the diagnosis input signal;
• the diagnostic circuit compares the diagnosis input signal and the diagnosis excitation signal to perform abnormality diagnosis of the excitation amplifier, and transmits a diagnosis result to the microcomputer;
• and
• the microcomputer performs normal activation of the system when the diagnosis result is normal, and executes processing appropriate for an abnormal part when the diagnosis result is abnormal.