In this case, anything could happen: an electrical wire could rot, any sensor could fail – that mean that any electrical component connected with the air suspension system could cause a switch to emergency mode. For diagnostics, you will need to connect a computer to the control unit. If only one sensor fails, the air suspension system may continue to operate normally, or it may fail at all.
Sometimes program crashes, and the «Air suspension is not programmed» message appears. The system automatically maintains an medium level. To solve the problem, you need to reflash the «brains» of the air suspension.