Just like the diag. trouble code description states, you may have developed a leak somewhere in the EAS (or a valve is stuck open.)
DTC: C113066
Description:
Air Spring Air Supply
Possible causes:
* Repeated or frequent level activity in the up direction
* Air spring leak
* Air harness leak
* Exhaust valve stuck open
* Corner valve leak to gallery
Action:
Visually inspect the system for air leakage. Refer to the guided diagnostic routine for this code on the approved diagnostic system.