Ford 6000CD Model. To display your serial number on the radio's screen press and hold buttons 1 & 6 together. This will prompt the radio to go into its code cycle. The V or M serial number will display towards the end of the cycle (for example V197905 ). Sometimes the serial is displayed across two screens, in this case, you will need to I recently had to replace my battery because of usage & very low temperatures. When I put the new battery I had to write the keycode. I put the keycode and Pi1Jkb.