Vehicle malfunction cause identifying device

A vehicle malfunction cause identifying device that identifies a cause for a malfunction in a vehicle using a detection value of an in-vehicle sensor when the malfunction has occurred in the vehicle, the in-vehicle sensor being equipped in the vehicle and detecting a behavior state of the vehicle,

• wherein:
• the vehicle malfunction cause identifying device identifies the cause for the malfunction in the vehicle by applying the detection value of the in-vehicle sensor when the malfunction has occurred in the vehicle to a malfunction cause identifying model of the vehicle malfunction cause identifying device that is preset using a second vehicle equipped with a first sensor and a second sensor, the first sensor being the same as the in-vehicle sensor, the second sensor being not equipped in the vehicle, a detection value of the second sensor allowing a cause for a malfunction in the second vehicle to be better identified relative to a detection value of the first sensor, the malfunction cause identifying model indicating a relation between the cause for the malfunction in the second vehicle identified based on the detection value of the second sensor and the detection value of the first sensor when the malfunction has occurred in the second vehicle,
• the malfunction is a faulty gear shift of a vehicle transmission including a hydraulic frictional engagement device, and
• the detection value of the second sensor is a value of an oil pressure of an operating oil by which an operating state of the frictional engagement device is switched.