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 inputs are needed in order to sense both the insertion of the ignition key and the power mode requested. 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:

• Activity on the serial data line.
• Detection of a battery disconnect and reconnect condition.
• Headlamps are ON.
• Ignition is turned ON.
• Key-in-ignition switch.
• Park lamps are ON.

The BCM will enter a sleep state when all of the following conditions exist:

• Ignition switch is OFF.
• No activity exists on the serial data line.
• 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 indicates that the BCM, which is the PMM of the vehicle, has sent an OFF-ASLEEP message to the other systems on the serial data line.