Abstract: An apparatus includes a linear solenoid valve regulating an oil pressure supplied to a clutch, a hydraulic switch being switched on and off upon receipt of a switching oil pressure, and a control unit controlling the actuation of the solenoid valve. A pressure-increased side signal oil pressure is detected which results when the hydraulic switch is switched on and off while a control signal is sent to the solenoid valve to increase a control oil pressure from a predetermined lower pressure to a predetermined higher pressure, and a pressure-decreased side signal oil pressure is detected which results when the hydraulic switch is switched on and off while the control signal is sent to decrease the control oil pressure from the predetermined higher pressure to the predetermined lower pressure. When a difference between these signal oil pressures exceeds an abnormalities determination value, it is determined that the solenoid valve is abnormal.

Abstract: An apparatus includes a linear solenoid valve regulating an oil pressure supplied to a clutch, a hydraulic switch being switched on and off upon receipt of a switching oil pressure, and a control unit controlling the actuation of the solenoid valve. A pressure-increased side signal oil pressure is detected which results when the hydraulic switch is switched on and off while a control signal is sent to the solenoid valve to increase a control oil pressure from a predetermined lower pressure to a predetermined higher pressure, and a pressure-decreased side signal oil pressure is detected which results when the hydraulic switch is switched on and off while the control signal is sent to decrease the control oil pressure from the predetermined higher pressure to the predetermined lower pressure. When a difference between these signal oil pressures exceeds an abnormalities determination value, it is determined that the solenoid valve is abnormal.

Abstract: At downshifting, hydraulic pressure of hydraulic clutch on engaging side (ON clutch pressure) is increased when an input and output speed ratio ("Gratio") has fallen below a predetermined value YGDNS. YGDNS is variably set depending on the vehicle speed and the engine temperature so that it becomes a lower value at a high vehicle speed than at a low vehicle speed, and a higher value at a low engine temperature than at a high temperature. When a downshifting command to a still lower speed stage is issued during downshifting control (when FTBD=1), a downshifting completion processing is performed in the course of the downshifting control (step in S111). Oil pressure in a hydraulic engaging element on the disengaging side QDNOFF and oil pressure in a hydraulic engaging element on the engaging side QDNON are switched to the oil pressures at the time of completion of downshifting, to thereby complete the first step downshifting control at an early time.

Abstract: Both shocks and time lag at the time of gear-in are reduced. For that purpose, the hydraulic pressure of a hydraulic engaging element to be engaged at the time of gear-in (in-gear pressure) QING is increased relatively rapidly at the beginning of gear-in. The speed of increase of QING is lowered after the input and output speed ratio "Gratio" of a transmission has exceeded a predetermined value YINGS which works as a basis for discriminating the start of engagement of the hydraulic engaging element.

Abstract: A facing surface of a clutch piston is previously moved to a position just before it abuts against an inner surface of a torque converter cover, or a position in which it extremely slightly abuts against the inner surface of the torque converter cover by outputting an initial engage pressure YMIN set in accordance with a vehicle speed and the like only for a predetermined time TMPS prior to the start of engagement of a lockup clutch. When the engagement of the lockup clutch is started, the engage pressure is gradually increased. When the engage pressure approaches a target pressure set in accordance with the target speed ratio, a feedback control of the engage pressure is carried out such that the actual speed ratio of the torque converter is converged to the target speed ratio. Thus, when the lockup clutch of the torque converter is brought into an engaged state, the responsiveness can be enhanced while preventing the generation of a shock.