Automatic transmission control apparatus

Claim 1

An automatic transmission control apparatus comprising: speed sensor means for detecting the velocity of a vehicle; throttle opening sensor means for detecting the throttle opening of an engine; shift position sensor means for detecting the position of a shift lever; rotational sensor means for detecting the rotation of the engine; shifting means for shifting the automatic transmission in accordance with the signals from said speed sensor means, said throttle opening sensor means and said shift position sensor means; and control circuit means including micro-computer means connected to said sensor means and said shifting means comprising means for detecting an abrupt loss of the signal from said speed sensor means; means for controlling said shifting means for shifting the automatic transmission to higher gear ratio in response to detection of said abrupt loss of signal; means for detecting when the engine rotation is under a predetermined level; and means for permitting the shifting of the automatic transmission in response to the position signal from said shift lever position sensor under a condition of failure of the vehicle velocity signal after detecting the abrupt loss of the vehicle velocity signal and detecting when the engine rotation is under said predetermined level.