Modules connected to the Class 2 data link monitor the link for serial data communications during normal vehicle operation. Operating information (Report messages) and commands (Load messages) are exchanged among the modules. When the inflatable restraint sensing and diagnostic module (SDM) receives a Report or Load message for a critical operating parameter, the SDM records the Source ID of the module which sent the message for State Of Health (SOH) monitoring (Node Alive messages). The SDM Does this after each ignition cycle. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once a Source ID is learned by a module, it will monitor for that Source ID's SOH message. Each module on the Class 2 data link which is powered and performing functions that require detection of communication malfunctions is required to send a SOH message every two seconds. When no message is detected from a learned Source ID, in this case the instrument panel cluster (IPC), for five seconds, a DTC U1096 is set. For more detailed information about the data lines, refer to Data Link Connector -- Cell 50.

The SDM sets DTC U1096.

The DTC will clear when one of the following conditions is met:

The following failures could cause a history DTC U1096 to set.

DTC U1096 will likely be set with DTC B1163 when communication is lost between the IPC and the SDM. Check that the IPC is functioning properly. Use the SOH DTC diagnostic information in Data Link Connector - Cell 50.