PURPOSE: To securely detect the disconnection of the ground line of a vehicle controller by reading in signals from respective sensors simultaneously and discriminating whether or not all of the signals from the sensors show corresponding variations at the same timing.
CONSTITUTION: When control is started, analog detected values of the respective sensors are taken out of a sample holder 42 simultaneously, A/D-converted 43, and then read in a control unit 25, thereby computing the quantities of variation in detected values of the respective sensors from those of the last scan. Then it is decoded by comparison whether or not all of the absolute values of the variation quantities of the detected values of the sensors are larger than a specific value. Here, when the analog ground line 44 is disconnected at, for example, time T1, the ground potential varies to a value determined by the mutual operation in the electrostatic charging states of the analog buffers 41 of the respective sensors. Thus, when the ground potential varies, the A/D-converted values of the detected values of all the sensors vary at the same timing. Then when the detected values of all the sensors are larger than the specific value, it is judged that the possibility of the disconnection of the line 44 is high.
NISHIMORI TAKAYOSHI
KAWAZOE SATORU
ABE MITSUTOSHI
