An engine control unit has a data memory for storing freeze frame data that is data indicating the operating status of vehicle equipment at the time when an abnormality of the vehicle equipment is detected. The engine control unit saves the freeze frame data stored in the data memory in a storage unit of a management station outside the vehicle through radio communication. The engine control unit determines the properness of the communication and performs a memory operation for erasing the relevant freeze frame data from the data memory based on a determination that the communication has been properly performed.