Class 2 Communication Malfunction: Description

Modules connected by class 2 serial data circuit monitor communications during normal vehicle operation. Operating information and commands are exchanged between modules. When a module receives a message for a critical operating parameter, receiving module records identification number of sending module for state of health monitoring. Critical operating parameter, if not received, requires receiving module to use default values for that parameter. If a module does not associate an identification number with at least one critical parameter within 5 seconds of beginning serial data communication, DTC U1000 will set, if DTCs U1300 or U1301 do not have current status. DTC U1000 will set only once if more than one critical parameter does not have an identification association.