Although the this is an old post, for those of you that have this issue when the truck bottoms out with the the shock and it says check suspension in the display, follow this test.
Take a floor jack and center it on the truck main frame rail near the front tire under the passenger door or the area near the bottomed out tire.
Start the vehicle, get out, shut the door. Jack the car up slowly about 1"-1 1/2" and stop, the compressor should start and refill the shock.
The reason why you need to do this is that the height sensor located on left and right front or rear have passed the lowest point of reference, hence the computer think there is a major issue and will not restart the compressor until the height sensor reaches its minimum data point that is programmed into the suspension module.

Trust me I know from first hand and verified with the dealer when they check that I have air bags that are leaking but only when cold out. I am now waiting for replacement shock from the company.
So every morning when it is cold out I have to jack up the truck 1" to kick on the compressor and I am good for the day. When it sits for more that 9-10 hours in cold at 45 or below, they dip. It is the internal o-ring constricting and shrinking. i have been dealing with this issue for 2 months in the northeast. I never had an issue last May to this Jan after I installed new shocks.

Hope this helps.