Ensure that you are in the ODO mode on the speedo readout. This means the total mileage showing up there. Power off car. While holding the ODO button below the screen (near the hazard button), power on the car. After the speedo 'dashes' go out and the numbers reappear, the light should go out and you can let go of the ODO button. If this doesn't work, try again! Love my Prius!