For those who like to dabble, the radio pin number is contained in the 24c08 EEPROM located on the main board under the casset or cd unit. its an 8 pin surface mounted IC in the middle towards the front.

the pin number is in location H0160 and H0161

example 12 34 01 pin number is 1234

a clip can be placed over the chip and the code downloaded with suitable software ( ponyprog?) or you can remove the chip and read it or replace

I'm currently working on reading the code over the j1850 can bus