A hydraulic system for an automatic transmission of a motor vehicle. A high-pressure circuit, in which a pressure accumulator, at least one clutch, and gear selectors and a hydraulic pump, which can be operated by an electronic control unit and by which the accumulator pressure in the high-pressure circuit can be increased in charging operation. A clutch valve that can be operated by the control unit is arranged in a clutch path between the pressure accumulator and a clutch hydraulic cylinder of the clutch, using which clutch valve a hydraulic pressure applied to the clutch hydraulic cylinder can be adjusted, and a safety valve that can be operated by the control unit is arranged upstream of the clutch valve.

An all-wheel-drive vehicle includes a primary drive axle, a secondary drive axle, and an all-wheel-drive powertrain configured to selectively power the primary and secondary axles. The powertrain includes a powerplant and a clutch that couples the powerplant to the secondary axle when engaged and that decouples the powerplant from the secondary axle when disengaged. A controller is programmed to disengage the clutch to disable all-wheel drive and propel the vehicle solely with the primary drive axle based on repeated occurrence of power output of the powertrain being less than a value.

A method for operating a drivetrain of a motor vehicle including at least one drive motor, a transmission device and at least one wheel which can be driven by the drive motor via the transmission device, in which respective actuations of respective shifting elements of the transmission device are brought about in order to influence thereby a transfer of a torque provided by the drive motor from the drive motor to the wheel via the transmission device, wherein—the torque provided by the drive motor is set as a function of a transfer function which indicates a factor by which the torque is to be multiplied, in order to calculate a wheel torque resulting from the torque and from the transfer and acting on the wheel.

A shift range control device is provided for a shift range switching system that includes a motor and a plurality of detectors. The motor has a plurality of winding sets. Each of the detectors is configured to detect a physical quantity that changes in accordance with rotation of the motor. The shift range control device includes a plurality of controllers configured to control switching of a shift range by controlling drive of the motor. Each of the controllers is provided to corresponding one of the winding sets and configured to acquire detection signals from the detectors, determine, based on the detection signals, a calculation signal having a same value between the controllers, and control, based on a target shift range and the calculation signal, a current supply to the corresponding one of the winding sets.

A diagnosis device determines diagnoses one of primary and secondary board temperature sensors as abnormal, in response to a condition that a state in which a primary temperature sensor value and a secondary temperature sensor value deviate from each other by a predetermined value or more continues for a predetermined duration or more; performs torque limitation to limit a torque inputted from an engine to an automatic transmission, during driving in a predetermined travel section based on a predetermined condition, after the one of the primary and secondary board temperature sensors is diagnosed as abnormal; and performs transmission shift restriction to restrict shifting of the automatic transmission along with the torque limitation, in response to a condition that the one of the primary and secondary board temperature sensors continues to be diagnosed as still abnormal after the driving in the predetermined travel section is completed.

A shift range control device is provided for a shift range switching system that includes a motor having winding sets and a motor rotational angle sensor. The shift range control device includes controllers configured to control switching of a shift range by controlling drive of the motor. Each of the controllers is provided to corresponding one of the winding sets, and is configured to acquire a motor rotational angle signal from the motor rotational angle sensor and calculate a motor angle, control drive of the motor by controlling a current supply to the corresponding one of the winding sets to make the motor angle become a target rotational angle corresponding to a target shift range, and drive the motor by sequentially switching a current-supplied phase for each predetermined period without using the motor rotational angle signal when the motor rotational angle signal is in fault.

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.

A shift range device switches a shift position. The shift range device includes a motor and an energizing unit. The motor functions as a power source for switching the shift position. The energizing unit energizes the motor. The shift range device monitors an abnormal state in which a magnetic field that causes a rotation of a rotor of the motor not to start or a holding magnetic field that stops the rotation generated in the rotor is incapable to be acquired.

An ECU has a temperature detection unit that detects an actual temperature of the ECU, a temperature estimation unit that calculates an estimated temperature of the ECU, an abnormality determination unit for determining a presence or absence of a sign of abnormality, and a switching prohibition unit that prohibits the shift range switching in a predetermined case. The switching prohibition unit prohibits the shift range switching when there is no sign of abnormality in the temperature detection unit and the actual temperature is equal to or higher than a switching prohibition threshold, and prohibits the shift range switching when there is a sign of abnormality in the temperature detection unit and the estimated temperature is equal to or higher than a switching prohibition threshold. The temperature estimation unit calculates the estimated temperature based on a latest actual temperature in a normal period.

Methods and systems are provided for controlling and diagnosing a mechanical vehicle component. In one example, a method may include determining a vehicle speed and a plurality of clutch position settings at a diagnostic controller, and identifying unauthorized conditions based on these determinations. Further, the diagnostic controller may trigger an active fault state of the mechanical vehicle component in order to avoid unauthorized conditions that may lead to unwanted or unanticipated changes in vehicle motion.