What does it mean when the sevice system stability message comes on? on 2007 Chevrolet Avalanche

I did buy the truck from the auction but, so far have everything down but the service sys stab, its been on all this time.

Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
1 answer
you will need to have someone run a diagnostic on this system to determine what codes are present. there are local
shops that have GM compatible software and the diagnosis
won't cost a lot.