Serial Data Messages

Modules that depend exclusively on serial data messages for power modes stay in the state dictated by last valid PMM message until they can check engine run flag status on serial data circuits. If PMM fails, modules monitor the serial data circuit for engine run flag serial data. If the engine run flag serial data is true, indicating engine is running, the modules fail-safe to "RUN". In this state modules and their subsystems can support all operator requirements. If engine run flag serial data is false, indicating engine is not running, modules fail-safe to "OFF-AWAKE". In this state modules are constantly checking for a change status message on serial data circuits and can respond to both local inputs and serial data inputs from other modules on vehicle.