My 2000 Mitsu Montero Sport required a battery change which of course wiped out the radio memory and I did not have the 4-digit "security" code (who the hell would want to steal this head unit anyway?). The radio numbers I got from the local dealer are as follows: MR472956190 - 3052 MR490089068 - 8207 Hope this helps someone out there.
I have a 2001 Montero Sport that had the same thing happen. I tried 3 codes and now have Off displayed (but hear if you turn key to ACC with radio on for about an hour it will reset). Not sure if 2000 and 2001 radio will be different but need to know how to get the radio out to get my ser # so I can get the code (or check if one of yours will work). Do you know how to remove the radio? Thanks!