Discrete IGNITION Signal Input Control
WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
Modules that have discrete IGNITION signal inputs also remain in state dictated by last valid PMM message received on serial data circuit. These modules check state of their discrete IGNITION input to determine current valid state. If discrete IGNITION input is active (battery positive voltage), modules will fail-safe to RUN power mode. If discrete IGNITION input is not active (open or 0 voltage), modules will fail-safe to OFF-AWAKE power mode. 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.