System for automatically controlling transmission for vehicles

Claim 1

An automatic transmission system in which a gear-shifting operation of a transmission is automatically carried out, said system comprising: a setting member for setting a gear-shifting mode of the transmission, generating means comprising a plurality of elements coupled with said setting member for generating electric information indicating an operation condition of said setting member, each of the elements producing a significant state of electric information only when said setting member is in a position corresponding to the element; malfunction detecting means for detecting whether or not there is a malfunction in said generating means, said malfunction detecting means comprising determination means for determining whether or not each element is producing it significant state, first means responsive to the determination means for detecting that a plurality of the elements are producing significant electric information at the same time, and second means responsive to the determination means for detecting that none of the elements is producing significant electric information; discriminating means for discriminating a nature of a malfunction in response to change in the electric information; output means responsive to said generating means, malfunction detecting means and discriminating means for providing a mode signal indicative of a mode of the gear-shifting operation; and a control unit responsive to said output means for carrying out a gear-shifting operation of the transmission in a gear-shift mode according to the mode signal.