Automatic Level Control Scan Tool Data Definitions:
The Automatic Level Control (ALC) Scan Tool Data Definitions contains a brief
 description of all scan tool parameters.
ALC Compressor: The scan tool displays Inactive/Active . The
scan tool will display Active when the vehicle trim height is below a preset value.
The ALC Compressor inflates the rear airlift shocks until the vehicle reaches the
desired trim height. When the vehicle is at the desired trim height, the scan 
 tool will display Inactive.
ALC Exhaust Solenoid: The scan tool displays Inactive/Active.
The scan tool will display Active when the vehicle trim height is above a preset
value. The ALC Exhaust Solenoid deflates the rear airlift shocks until the vehicle
reaches the desired trim height. When the vehicle is at the desired trim height,
the scan tool will display Inactive.
Battery Voltage Signal: The scan tool displays 0-26.0
 volts. The battery voltage represents the system voltage measured at the controller
 battery input.
DSP Software Version: The scan tool displays the controller
 DSP software version number for service identification.
EEPROM Calibration ID: The scan tool displays the controller
 EEPROM calibration ID number for service identification.
GM Part Number: The scan tool displays the controller part number
 for service identification.
GMSCM Software Version: The scan tool displays the controller
 GMSCM software version number for service identification.