If Required, Enter Code in Head Unit First. Press And Hold " CD.C" Button The Display Shows "CD Player" Then "0000" Press preset " 1 " repeatedly for 1st Digit Press preset " 2 " repeatedly for 2nd Digit Press preset " 3 " repeatedly for 3rd Digit Press preset " 4 " repeatedly for 4th Digit If the correct code number is now shown Press Tuning Up Button " ^ " To Enter