Abnormality treatment device for automatic transmission control device

An abnormality treatment device for a control device for an automatic transmission including a speed change gear mechanism whose power transmission passage is connected to an output shaft of an engine and changed by means of hydraulically operated friction means to obtain a plurality of speed ranges, said treatment device including a speed range selection judgement circuit for receiving respective signals from an engine load sensor generating engine load signals corresponding to engine loads and from a vehicle speed sensor generating vehicle speed signals corresponding to vehicle speeds, comparing these signals with values corresponding to predetermined engine load and vehicle speed and determining said speed range and operation of said friction means, and a hydraulic control judgement circuit for receiving the signals from said engine load sensor to operate a hydraulic regulator valve, said treatment device comprising, in its input portion receiving the signals from said engine load sensor and said vehicle speed sensor, an abnormal value detection circuit for detecting an abnormal value of any one of said respective signals to generate an abnormal value detection signal, and an abnormality treatment circuit for producing abnormality treatment signals to be fed to said speed range selection judgement circuit and said hydraulic control judgement circuit in response to said abnormal value detection signal, thereby upon detection of the abnormal value signal, enabling said speed range selection judgement circuit and said hydraulic control judgement circuit to maintain a predetermined speed range and a predetermined high pressure, respectively.