Circuit/System Description
WARNING: This page is about a different car, the 2008 Saturn Outlook, 2008 GMC Acadia, and 2008 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
Ignition voltage is supplied to the engine mount solenoid. The EBCM monitors engine RPM over GMLAN and activates the mount solenoid when engine speed is below 1200 RPM reducing engine vibration at idle.