Patent ID: 7682275

Claim:
An automatic transmission control apparatus comprising: a shift control section configured to issue instructions to selectively engage and disengage a combination of a plurality of frictionally engaging elements of a planetary gear mechanism to establish a corresponding one of a plurality of gear ratios; a first rotary-speed detecting section configured to detect a rotational speed of a first rotary member of the planetary gear mechanism which rotates at a different speed from an input shaft of the planetary gear mechanism; a second rotary-speed detecting section configured to detect a rotational speed of a second rotary member of the planetary gear mechanism which rotates at a different speed from the input shaft of the planetary gear mechanism; an input shaft speed calculation section configured to calculate a rotational speed of the input shaft using values detected by the first and second rotary-speed detecting sections; an output shaft speed detection section configured to detect a rotational speed of an output shaft of the planetary gear mechanism; a gear ratio calculation section configured to calculate a gear ratio from the rotational speed of the input shaft calculated by the input shaft speed calculation section and the rotational speed of the output shaft detected by the output shaft speed detection section; a neutral determination section configured to determine if the automatic transmission has failed and a neutral state has been established due to an occurrence of an engagement malfunction of one the frictionally engaging elements, based on the gear ratio calculated by the gear ratio calculation section; and a neutral control section configured to conduct a neutral control by forcing the automatic transmission to shift to a non-malfunctioning gear ratio upon the neutral determination section determining that the automatic transmission failed and is in the neutral state when the shift control section issues instructions to establish an appropriate one of the gear ratios for driving.