2004 Deville Stability System message how to view codes
 

Hello there. I have a 2004 Cadillac Deville that I recently acquired from a relative. For years it has flashed the "Service Stability System" on the LED readout on the dash once you start driving it. I hook a computer code reader up to the car and it says the cars is not giving off any codes. How can I get more information on what specifically is causing this issue?