An ECU executes a program that includes the steps of setting an abnormality flag when a hydraulic pressure switch is on even though a lock-up clutch is in a lock-up OFF state, forcing an SLU off when the lock-up clutch is on and the abnormality flag is on, determining that there is an SLU failure when the lock-up clutch is still in a lock-up ON state after a predetermined period of time has passed, and determining that there is a hydraulic pressure switch failure when the lock-up clutch is not in the lock-up ON state after the predetermined period of time has passed.