An information processing apparatus includes a communication apparatus and a different communication apparatus connected to the communication apparatus via a plurality of transmission paths. The communication apparatus includes a transmitting unit and a control unit. In response to designation of a transmission path targeted for diagnosis, selected amongst the transmission paths while the communication apparatus is in a state capable of data communication with the different communication apparatus using the transmission paths, the transmitting unit transmits a test signal to the targeted transmission path while the state capable of data communication with the different communication apparatus is maintained using remaining transmission paths of the transmission paths other than the targeted transmission path. The control unit diagnoses the presence or absence of an abnormality sign in the targeted transmission path based on the result of detecting the test signal in the targeted transmission path and outputs the diagnostic result.