BCM Wake-Up/Sleep States

The BCM is able to control or perform all of the BCM functions in the wake-up state. The BCM enters the sleep state when active control or monitoring of system functions has stopped, and the BCM has become idle again. The BCM must detect certain wake-up inputs before entering the wake-up state. The BCM monitors for these inputs during the sleep state, where the BCM is able to detect switch transitions that cause the BCM to wake-up when activated or deactivated. Multiple switch wake-ups are needed in order to sense both the insertion and the removal of the ignition key. This would allow the BCM to enter a sleep state when the key is IN or OUT of the ignition.

The BCM will enter a wake-up state if any of the following wake-up inputs are detected:
^ Any activity on the serial data line
^ Hatch ajar switch
^ Hatch release switch
^ Door ajar switch
^ Key-in-ignition switch
^ Monitored load relay
^ Park/fog/headlamps are on
^ The BCM experiences a battery disconnect and reconnect condition.
^ The ignition is turned ON.

The BCM will enter a sleep state when all of the following conditions exist:
^ No activity exists on the serial data line.
^ The ignition switch is OFF.
^ No outputs are commanded.
^ No delay timers are actively counting.
^ No wake-up inputs are present.

If all these conditions are met the BCM will enter a low power or sleep condition. This condition would indicate the BCM, which is the power mode master of the vehicle, must have sent a message to the other systems on the serial data line to stop broadcasting their state of health messages.