1. Press MENU # 1 9 3 4 in sequence rapidly. The LCD panel should now display TECH. 2. Press MENU, and then press ENTER. The LCD panel will display Tech Mode. 3. Press the left arrow (<) button once. The operator panel will display NEW CARTRIDGE. 4. Press ENTER. The operator panel will display [YES]. 5. Press ENTER. The toner warning message should be gone. 6. To exit TECH MODE, press MENU # 1 9 3 4 in rapid succession, as if you were dialing a phone number. The operator panel should no longer display TECH.