Impala V6-3.8L SC VIN 1 (2005)
The modules that depend exclusively on serial data messages for power modes stay in the state dictated by the last valid BCM message until they can
check for the engine run flag status on the serial data circuits. If the BCM fails, the modules monitor the serial data circuit for the engine run flag serial
data. If the engine run flag serial data is True, indicating that the engine is running, the modules fail-safe to RUN. In this state the modules and their
subsystems can support all operator requirements. If the engine run flag serial data is False, indicating that the engine is not running, the modules
fail-safe to OFF-AWAKE. In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to
both local inputs and serial data inputs from other modules on the vehicle.
DISCRETE IGNITION SIGNALS
Those modules that have discrete ignition signal inputs also remain in the state dictated by the last valid BCM message received on the serial data
circuits. They then check the state of their discrete ignition input to determine the current valid state. If the discrete ignition input is active, B+, the
modules will fail-safe to the RUN power mode. If the discrete ignition input is not active, open or 0 voltage, the modules will fail-safe to
OFF-AWAKE. In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local
inputs and serial data inputs from other modules on the vehicle.
