Anomaly determination device for power transmission device

An anomaly determination device for a power transmission device, wherein the anomaly determination device is used for a vehicle including the power transmission device and an oil temperature sensor, the power transmission device includes a frictional engagement element and is configured to transmit power output from a power source of the vehicle to a driving wheel, and the oil temperature sensor is configured to detect an oil temperature, which is a temperature of oil circulating in the power transmission device, the anomaly determination device comprising:

• processing circuitry;
• and
• a storage device, wherein
• the storage device stores a mapping data entry that specifies a mapping and includes data learned through machine learning,
• a detection value of the oil temperature sensor is an oil temperature detection value,
• when oil temperature relation data, which is data corresponding to time series data of the oil temperature detection value, is input to the mapping as an input variable, the mapping outputs an output variable that determines whether the frictional engagement element has an anomaly,
• the processing circuitry is configured to execute
• an obtainment process that obtains the input variable, and
• an anomaly determination process that determines whether the frictional engagement element has the anomaly based on the output variable that is output from the mapping as a result of inputting the input variable obtained in the obtainment process into the mapping.