BCM Wake-Up/Sleep States

The body control module (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.

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.
• RFA message

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

• The 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 power mode master (PMM) of the vehicle, has sent an OFF or OFF-ASLEEP message to the other systems on the serial data line.