2010 Cadillac Escalade Esv No Electronic steering

Diagnostic steps? I work for a used car lot and we have no mitchell or alldata. The customer said that he came out this morning and there was no power steering. I checked for fluid and there was no hydrolic power steering on the car it has electronic steering. I checked for blown fuses and looked to see if it had any relays for the steering. I have no training on electronic steering and need help in finding the diagnostic flow chart.