Circuit Description

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the ID number of the module which sent the message for State of Health monitoring, Node Alive messages. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. When a module does not associate an ID number with at least one critical parameter within about 5 seconds of beginning serial data communication, DTC U1000 is set. When more than one critical parameter does not have an ID number associated with it, the DTC will only be reported once. DTC U1000 will set as long as U1300 or U1301 do not have a current status.

The table below list the modules on the class 2 serial data circuit that will set a U1000 and should be actively communicating the previously described messages on the class 2 serial data circuit.