There are four digit codes for VIZIO TVs, which are: 0171, 0451, 0512, and 0660. To enter these codes, press the Menu button on your remote control, then arrow over to the Settings icon and press Enter. Select the TV Setup option and press Enter again. Use the arrow keys to scroll down to the Input Lock Code setting and press Enter. Type in one of the four-digit codes listed above and press Enter again to lock or unlock that code.