Press and hold the On/Off and Info Up buttons at the same time until all the dash lights go on. It will then display "All?". Press the On/Off button and it will say "All Codes?". Press the On/Off button once more and it will begin to read off the codes. Get a pen or pencil ready. If you miss any, you can always use the info button to scroll back through the menu and read the codes off again, using the On/Off button to select each option.