Circuit Description

Each module connected to the class 2 serial data circuit monitors 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 identification number of the module which sent the message for state of health monitoring. Once an identification number is learned by a module, it will monitor for that modules node alive message. Each module on the class 2 serial data circuit is required to send a node alive message every 2 seconds. When a control module does not detect a node alive message from a learned identification number for 5 seconds, DTC U1001-U1254 will set.