Discrete Ignition Signals
WARNING: This page is about a different car, the 2006 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
Those modules that have Run/Crank discrete ignition signal input also remain in the state dictated by the last valid power mode message from the BCM or the RCDLR. They then check the state of their Run/Crank discrete ignition signal input to determine the current valid state. If the discrete ignition input is active, the modules will fail-safe to the "Run" power mode. If the discrete ignition input is inactive, the modules will fail-safe to "Off" power mode.