Circuit/System Description (W/O F55)
WARNING: This page is about a different car, the 2009 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
The automatic level control (ALC) module adjusts the vehicle suspension ride height. The ALC module determines the height of the vehicle based on the voltage from the suspension position sensor. The module grounds the ELC relay and the exhaust control solenoid to raise and lower the vehicle in order to keep the vehicle level.