A multi-speed planetary transmission is operable in at least nine forward speed ratios, at least one reverse speed ratio, and at least one neutral speed ratio. A hydraulic control system for the transmission includes a hydraulic default control system and is operable to a default configuration when a default condition occurs during operation of the transmission. The hydraulic control system defaults to a forward default gear ratio during operation of the transmission in a first forward speed ratio and defaults to a default neutral speed ratio during operation of the transmission in a reverse speed ratio when a default condition occurs. The default condition may be a transmission control module (“TCM”) power failure.

A control device for a vehicle including (i) a power transmission device, (ii) a shift operation device that is to be operated by a driver of the vehicle to an operation position corresponding to a shift position of the power transmission device, and (iii) a switching device for switching the shift position of the power transmission device through actuation of an actuator. The control device is configured, upon occurrence of a momentary interruption of a control-device electric-power source that is supplied with an electric power from a vehicle electric-power source, to not perform an initial position learning process for setting a reference position of the actuator, until a shift switching operation for switching the shift position of the power transmission device is performed by a driver of the vehicle.

The control device is configured to supply an offset current value to disengagement solenoids of disengagement-side friction engaging elements among a plurality of shift solenoids that control respective shift oil pressures applied to the plurality of friction engaging elements, and when a current gear position is a first speed position or a reverse position, decrease a current value to be supplied to at least one of the disengagement solenoids that are supplied with the offset current value to be lower than the offset current value.

The control device is configured to supply an offset current value to disengagement solenoids of disengagement-side friction engaging elements among a plurality of shift solenoids that control respective shift oil pressures applied to the plurality of friction engaging elements, and when a current gear position is a first speed position or a reverse position, decrease a current value to be supplied to at least one of the disengagement solenoids that are supplied with the offset current value to be lower than the offset current value.

A load drive system, capable of providing certainty about instructions transmitted from a load control device to a load drive device as well as suppressing an increase of processing load, includes an ECU, a drive device, a communication bus to which the ECU and the drive device are connected, and a third signal line different from the communication bus connecting the ECU and the drive device. The ECU generates a frame including a drive instruction message, and transmits the message to the drive device via the communication bus. The drive device receives the frame via the communication bus, and extracts the drive instruction message from data of data field in the received frame. The drive device converts the drive instruction message into a load drive signal, and notifies the converted load drive signal to the ECU via the third signal line.

The disclosure provides a control method, a control device for vehicular automatic transmission, and a recording medium. The control device includes an ON/OFF control solenoid controlling LC to either ON or OFF, and an LC pressure control linear solenoid controlling LC pressure between a released state and a fully engaged state. The control device acquires, when an accelerator pedal opening of a vehicle is on a deceleration side in a fully closed state, a torque converter slip ratio when the ON/OFF control solenoid maintains ON for a predetermined time period and the LC pressure control linear solenoid is controlled such that the LC pressure is OFF, and determines whether or not the second solenoid has a high-pressure fixation failure according to whether or not the slip ratio is within a predetermined range from a slip reference value.

A shift range control device includes an encoder count unit, an energization control unit, a learning unit, an energization phase count unit, and an abnormality determination unit. The encoder count unit calculates an encoder count value based on an encoder signal. The energization control unit controls energization to the motor. The learning unit learns a wall position that is the encoder count value when an engaging member abuts on the wall portion. The energization phase count unit calculates an energization phase count value that is counted according to switching of the energization phase. The abnormality determination unit determines an abnormality of the encoder based on the energization phase count value and the encoder count value before and after learning the wall position.

A shift range control device includes a plurality of control units provided for each of motor windings. When a motor rotation angle sensor is normal, a drive control unit controls an energization of the motor winding of its own system by using a motor rotation angle signal. When the motor rotation angle sensor has an abnormality and it is determined that an output shaft is rotating before a standby time elapses, the drive control unit does not energize the motor winding of its own system. When it is determined that the output shaft is not rotating even after the standby time has elapsed, the drive control unit controls the energization of the motor winding of its own system without using the motor rotation angle signal.

A vehicle control device for a vehicle with a drive source and an automatic transmission including a friction engaging element for transmitting a driving force of the drive source to drive wheels by being engaged by a hydraulic pressure, wherein the vehicle control device is configured to perform an abnormality diagnosis of a solenoid valve for adjusting a hydraulic pressure to be supplied to the friction engaging element on the basis of a slip amount of the friction engaging element, and prohibit the abnormality diagnosis of the solenoid valve if a hydraulic pressure upstream of the solenoid valve is below a predetermined hydraulic pressure at which the friction engaging element is engaged, the hydraulic pressure upstream of the solenoid being a source hydraulic pressure to be adjusted by the solenoid valve.

A multi-speed planetary transmission is operable in at least nine forward speed ratios, at least one reverse speed ratio, and at least one neutral speed ratio. A hydraulic control system for the transmission includes a hydraulic default control system and is operable to a default configuration when a default condition occurs during operation of the transmission. The hydraulic control system defaults to a forward default gear ratio during operation of the transmission in a first forward speed ratio and defaults to a default neutral speed ratio during operation of the transmission in a reverse speed ratio when a default condition occurs. The default condition may be a transmission control module (“TCM”) power failure.