WHAT IS THE CUSE OF CAR STOP WHEN THE TRACTION LIGHT ON?

No idea. If it happened only one time, it's difficult to determine why without inspecting the car. More importantly, the traction control light is on. When the light is on, the system is inoperative and therefore a safety issue, you need to address this ASAP. The traction control light indicates that the computer has detected a malfunction in the traction control system and has diagnostic codes and data stored which would be essential in diagnosing the problem. A technician with a scanner can access the diagnostic codes and data and then be able to give you a diagnosis. If you want to find a GM specialist, here's our directory link for you: https://repairpal.com/gmc-repair-in-arab-alabama