A PWM control part rotationally drives a motor based on a PWM control value. A rotation speed control part controls a rotation speed of the motor. A rotation angle detection part detects a rotation angle of the motor. A reference position learning part controls the motor to rotate at a constant rotation speed until a detent plate stops at a limit position of a movable range and learns a reference position of the motor. A current detection circuit detects a current value corresponding to a driving current. A current limitation part limits a current supplied to the motor. A PWM control value limitation part controls the PMW control value to be equal to or smaller than a PWM limitation value, which is a predetermined value. A relation check part checks whether a relation between a current value detected by the current detection circuit and the PWM control value is inappropriate.

A method for monitoring a fixed-gear transmission includes deriving a node speed relationship for each of the planetary gear sets based upon a center distance and a gear ratio and determining equivalent speed parameters for nodes of the planetary gear sets based upon a transmission input speed state, an intermediate node speed state and a transmission output speed state. A clutch slip speed relationship is determined for each of the clutches based upon the node speed relationships for the planetary gear sets and the equivalent speed parameters for nodes of the planetary gear sets. Rotational speed sensors monitor the input transmission speed, the intermediate node speed and the transmission output speed. A clutch slip speed for each of the clutches is determined based upon the respective clutch slip speed relationship and the monitored input transmission speed, the monitored intermediate node speed and the monitored transmission output speed.

A method for monitoring a fixed-gear transmission includes deriving a node speed relationship for each of the planetary gear sets based upon a center distance and a gear ratio and determining equivalent speed parameters for nodes of the planetary gear sets based upon a transmission input speed state, an intermediate node speed state and a transmission output speed state. A clutch slip speed relationship is determined for each of the clutches based upon the node speed relationships for the planetary gear sets and the equivalent speed parameters for nodes of the planetary gear sets. Rotational speed sensors monitor the input transmission speed, the intermediate node speed and the transmission output speed. A clutch slip speed for each of the clutches is determined based upon the respective clutch slip speed relationship and the monitored input transmission speed, the monitored intermediate node speed and the monitored transmission output speed.

An abnormality determination device for a continuously variable transmission is provided in which since the abnormality determination device which calculates a compression stiffness of a metal belt from an amplitude ratio between a variable component of the rotational speed of an input shaft and a variable component of the rotational speed of an output shaft, a phase lag that is an indicator of the difference in phase between a variable component of the rotational speed of the input shaft and a variable component of the rotational speed of the output shaft, and a belt pitch radius of a drive pulley or a driven pulley, and determines whether a metal ring has broken by comparing the compression stiffness of the metal belt with a preset reference compression stiffness.

There is obtained an automatic transmission control apparatus that makes it possible that even when an abnormality occurs in a sensor for detecting a motor rotation angle or the like, control of an automatic transmission is appropriately performed. Inputted first, second, and third detection signals are compared with one another; it is determined that at least two detection signals, out of these detection signals, that coincide with each other are normal and another detection signal is abnormal; then, based on the result of the determination, switching of the ranges of the automatic transmission is controlled.

There is obtained an automatic transmission control apparatus that makes it possible that even when an abnormality occurs in a sensor for detecting a motor rotation angle or the like, control of an automatic transmission is appropriately performed. Inputted first, second, and third detection signals are compared with one another; it is determined that at least two detection signals, out of these detection signals, that coincide with each other are normal and another detection signal is abnormal; then, based on the result of the determination, switching of the ranges of the automatic transmission is controlled.

Under an abnormal determination, when a transmission gear stage is switched, a torque limit value is changed from a value before switching of the transmission gear stage to a value after switching thereof in a period in which this transmission gear stage is switched.

Under an abnormal determination, when a transmission gear stage is switched, a torque limit value is changed from a value before switching of the transmission gear stage to a value after switching thereof in a period in which this transmission gear stage is switched.

A vehicle includes a prime mover, transmission, drive axle, and controller. The controller identifies clutches involved in establishing or maintaining a requested gear state, and detects an impending fault condition of the transmission. The controller also executes a pre-remedial control action in response to the impending fault condition, and places the transmission in a hydraulic default mode when the remedial control action does not clear the fault condition after a calibrated duration. A system includes the transmission and controller. A method for providing pre-remedial control of a transmission includes identifying clutches of the transmission that are involved in establishing or maintaining a requested gear state, and detecting an impending fault condition. The method further includes executing a pre-remedial control action in response to the impending fault condition and placing the transmission in a hydraulic default mode if the remedial control action does not clear the fault condition.

A vehicle includes a prime mover, transmission, drive axle, and controller. The controller identifies clutches involved in establishing or maintaining a requested gear state, and detects an impending fault condition of the transmission. The controller also executes a pre-remedial control action in response to the impending fault condition, and places the transmission in a hydraulic default mode when the remedial control action does not clear the fault condition after a calibrated duration. A system includes the transmission and controller. A method for providing pre-remedial control of a transmission includes identifying clutches of the transmission that are involved in establishing or maintaining a requested gear state, and detecting an impending fault condition. The method further includes executing a pre-remedial control action in response to the impending fault condition and placing the transmission in a hydraulic default mode if the remedial control action does not clear the fault condition.