Patent ID: 7903539

Claim:
An electronic control unit comprising: an input interface including: a plurality of multiplexer circuits that input a plurality of input signals respectively and output one of the input signals to their output terminals selectively, the plurality of input signals being supplied from an outside of the electronic control unit; an abnormality detecting multiplexer circuit that has aplurality of input terminals which are set at ground potential or given potential; select signal lines that are connected to the plurality of multiplexer circuits and the abnormality detecting multiplexer circuit respectively, that provide a first select signal to the plurality of multiplexer circuits, the first select signal dictates a signal the plurality of multiplexer circuits output to their output terminals, and that provide a second select signal to the abnormality detecting multiplexer circuit, the second select signal dictating a potential the abnormality detecting multiplexer circuit outputs to its output terminal; a determining portion that inputs a plurality of input signals outputted from the output terminals of the plurality of multiplexer circuits, that transmits the second select signal to the abnormality detecting multiplexer circuit through the select signal lines when determining that the input signals have an abnormal state, that determines whether or not the second select signal is supplied to the abnormality detecting multiplexer circuit through the select signal lines based on the potential the abnormality detecting multiplexer circuit outputs in response to the second select signal, and that determines an abnormality occurs in the select signal lines when determining that the second select signal is not supplied to the abnormality detecting multiplexer circuit; and a failsafe processing part that executes a failsafe process using the input signals supplied before an abnormality in the select signal lines is detected when the determining portion determines that the abnormality occurs in the select signal lines, and determines the abnormality occurs in the input signals when the determining portion determines no abnormality occurs in the select signal lines and that executes a failsafe process based on an abnormal state of the input signals.