Why would the message center display the message that the 'Terrain Responce System Not Available'?

The suspension would not come out of the lowered position the other day and that's the message that was displayed.

 

There are numerous faults that can cause that. Culprits could be bad height sensor, transmission fault, suspension compressor, bad engine wiring.......

Get it into the dealer asap and then can connect their computer to see what fault was recorded in the system.