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
^ Parking/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.

Power Requirements
The BCM has two main power feeds (high and low current), and two main grounds. The low power feed (battery 1) is used to provide power for the BCMs logic and internal driver operation. The high power feed (battery 2) is used to provide power for systems that draw higher amounts of current (motors, lights, etc.). Operating current at the BCMs battery should not exceed 3.0 amperes at battery 1, and 7.5 amperes (for 2 seconds) at battery 2 while the BCM is awake, and 2.5 milliamps when the BCM is asleep. For most BCM functions, the BCM will operate properly with a system voltage of 9.0-16.0 volts. If system voltages exceed 16.0 volts the BCM will provide protection by disabling certain functions that may damage due to higher than normal system voltages.