Control system with malfunction detecting device for use in motor vehicle

A control system for use in a motor vehicle comprising:

• sensor means for sensing an operating state of said motor vehicle and outputting an analog sensor signal indicative thereof;
• reference voltage generating means for generating a predetermined reference voltage signal;
• analog-to-digital converting means for converting an inputted analog signal into a digital signal;
• switching means, connected to said sensor means, said analog-to-digital converting means and said reference voltage generating means, for switching between said analog sensor signal and said predetermined reference voltage signal and supplying said analog-to-digital converting means with one of said analog sensor signal and said predetermined reference voltage signal;
• first decision means for deciding whether a first output signal represents an abnormal value, said first output signal being a signal obtained by said analog-to-digital converting means converting said analog sensor signal to a digital sensor signal;
• and
• second decision means for activating said switching means, after said first decision means determines that said first output signal represents said abnormal value, so that said predetermined reference voltage signal is supplied from said reference voltage generating means to said analog-to-digital converting means and for determining whether a second output signal represents said predetermined reference voltage signal, said second output signal being a signal obtained by said analog-to-digital converting means converting said predetermined reference voltage signal to a digital reference voltage signal.