That error is associated with your air compressor, part of the air suspension system. Before firing the parts cannon, do you hear the air compressor start up and run for 5 or so seconds, when you start up your truck? If yes, make a soap and water mix in a spray bottle and spray in on the rear shocks, both where the air line attaches to the shocks and on the rubber air bags. Do you see any bubbles, indicating an air leak? If you see air bubbles, then your shocks are leaking and need to be replaced.
If you do not hear the compressor start up, first check the fuse for the compressor in the fuse box in the engine well. If the fuse is good, you most likely need a replacement compressor. Rock Auto has Dorman air compressors for your truck for under $200.