Communication failure detection device

A communication failure detection device configured to detect a communication failure of a two-wire CAN communication device that makes communication between nodes according to a CAN protocol,

• the communication failure detection device comprising:
• two signal detection circuits that are provided in each of the nodes and that are configured to detect signals on two communication lines, wherein
• each of the nodes is configured to make communication for failure identification that outputs signals of predetermined patterns onto the two communication lines when an execution condition is satisfied in response to occurrence of a protocol error of CAN communication and to perform failure identification that identifies a type of a failure based on a combination of the signals respectively detected by the two signal detection circuits during the communication for failure identification, wherein
• the execution condition is satisfied when each of the nodes fails to make normal communication for a first predetermined time period, and
• each of the nodes continues the communication for failure identification for a second predetermined time period, and wherein
• the second predetermined time period is longer than the first predetermined time period.