Circuit Description
WARNING: This page is about a different car, the 2005 Saturn L300. However, it is still accessible from the selected car via links, so may be relevant.
Normal vehicle class 2 communications and module operations will not begin until the system power mode has been identified. Discrete circuits from the ignition switch are monitored by the power mode master (PMM) module in order to determine the correct power mode. The PMM communicates the system power mode to all class 2 modules on the class 2 serial data line. The body control module (BCM) is the PMM on this vehicle. Use this table if the class 2 power mode does not match the ignition switch position.