FAILURE DETERMINATION DEVICE FOR STEPLESS SPEED CHANGER AND FAILURE DETERMINATION DEVICE FOR START CLUTCH

摘要

A failure determination device for a belt-type stepless speed changer, the device being capable of specifying a failure of a control valve that performs speed change operation and enhancing maintainabilty of the speed changer. While a vehicle is in stop, an ECU controls the speed change ratio of the speed changer so as to be within a LOW-side range for seizure determination. When a speed change ratio while the vehicle is in stop is in an OD-side range at stop, the ECU determines that a DR solenoid valve is in failure when engine torque, TQEG, is equal to or greater than DR-side determination torque at OD, TQDRJD, and a speed change ratio, RATIO, is less than a determination value for DN, RTDNJD. Also, the ECU determines that a DN solenoid valve is in failure when throttle valve opening, TH, is equal to or greater than an OD-side determination value, THDRDNJD, RATIO is equal to or greater than RTDNJD, and a vehicle speed, VP, is less than an OD-side determination value, VDRDNJD.