What does it mean wen the traction control light comes on and stays in a 1999 Toyota Avalon?

When the traction control light comes on and stays on in a 1999 Toyota Avalon, it indicates that the traction control system has been activated. This means the vehicles traction control computer has detected a loss of traction on one or more of the vehicles wheels .The traction control system will try to compensate by reducing engine power and /or applying some brakes the affected .