There are a few reasons why the "Trac Off" light might come on and stay on. One possibility is that the traction control system has been manually disabled by the driver. This can be done by pressing the "Trac Off" button on the vehicle's dashboard. Another possibility is that the traction control system has detected a problem and has automatically disabled itself. This could be due to a problem with the traction control system itself, or it could be due to a problem with another system in the vehicle, such as the ABS brakes or the engine.
If the "Trac Off" light comes on and stays on, it is important to have the vehicle inspected by a qualified mechanic to determine the cause of the problem. Driving with the traction control system disabled can increase the risk of an accident, so it is important to have it repaired as soon as possible.