Fortunately/unfortunately, '03 and newer Porsches do not require a radio code being entered manually. They utilize the MOST fiber optic set up where each component in the authorized loop electronically "shakes hands" with the other components.
That said, you'll need someone w/ the PSTII or PIWIS system (Porsche diagnostics tools) to find the source of your error. Or, you can try and reset all the electronics in the vehicle by disconnecting the cables from both battery terminals. Then, with cables still disconnected, use a box wrench/wire hanger or the like and connect the cables (not the batter terminals
) to each other for at least 30 seconds (maybe a minute). This will ground out the system to itself and reset everything. Then, reconnect the (+) terminal and then the (-). You'll have to reset your clocks, window stops for auto up/down etc. This may be enough to reboot the MOST loop in your car to recognize each component.
Otherwise, as I previously mentioned, you'll need someone w/ the Porsche diagnostic tools to find the error. The CDR 23 radios (which you have) are known to have issues as well as the corresponding amps.
Good luck
