Controller of power transmission system for vehicle

A controller of a power transmission system for a vehicle, the power transmission system including a continuously variable transmission, a continuously variable transmission connecting and disconnecting device, an electromagnetic control valve for a secondary pulley, and a hydraulic pressure sensor, the continuously variable transmission having a primary pulley, the secondary pulley, and a transmission element looped around the primary pulley and the secondary pulley, the continuously variable transmission being provided in a first power transmission path through which power of a drive power source is transmitted to an output shaft, the continuously variable transmission connecting and disconnecting device being provided in the first power transmission path and configured to connect and disconnect the first power transmission path, the electromagnetic control valve for the secondary pulley being configured to control a secondary pressure supplied to the secondary pulley, by use of a command pressure, the hydraulic pressure sensor being configured to determine an actual pressure supplied to the secondary pulley,

• the controller comprising an electronic control unit, wherein
• when a difference between the secondary pressure set by use of the command pressure of the electromagnetic control valve for the secondary pulley, and the actual pressure obtained by the hydraulic pressure sensor, is larger than a predetermined pressure difference, during traveling using the first power transmission path, the electronic control unit causes the continuously variable transmission connecting and disconnecting device to disconnect the first power transmission path, and sets a primary pressure supplied to the primary pulley and the secondary pressure supplied to the secondary pulley, by use of respective command pressures determined such that a speed ratio of the continuously variable transmission becomes substantially equal to a maximum value, and
• the electronic control unit determines that there is an abnormality that an output pressure of the electromagnetic control valve for the secondary pulley is low, when the speed ratio of the continuously variable transmission is smaller than a predetermined first determination value, and determines that there is an abnormality in the hydraulic pressure sensor, when the speed ratio of the continuously variable transmission is larger than a predetermined second determination value.