Turning the key to the on position(not start) and then back off three times will trigger the check engine light to flash codes. Ex. The light may flash 3 times, have a short pause and then flash 4 times = code 34. Then there will be a longer pause between codes.
"Shiny side up, Greasy side down"
"Where's the shiny side?"
"Brown side up, Greasy side down" - Piper54