US Patent 11449381 Apparatus and method for diagnosing communication fault

Provided is an apparatus and method for diagnosing a communication fault. The apparatus includes a first slave module, a second slave module and a master module. The first slave module receives a synchronization signal through the first communication line and a first output signal through the second communication line, and transmits an input signal through the third communication line. The second slave module receives synchronization signal through the first communication line, and transmits a comparison signal to the master module through the third communication line when the second slave module receives a second output signal through the second communication line. The master module transmits the synchronization signal, the first output signal and the second output signal, and diagnose a communication fault by comparing a value of the comparison signal with a predetermined reference value or a value of the input signal.