Has it been ever showing "CODE"?
Some Nissan radios have a NATS protection system instead of a numerical code. These radios will indicate "SECURE" if they are fitted into another car. There is nothing that a customer can do to reactivate the radio in the new car - it must be reset by a Clarion service centre or another decoding specialist.
If yours has a traditional numerical code: "SECURE" message should have come on because several invalid attempts to enter the code were made. Just leave the radio powered on, undisturbed. After 4 hours (or less), it should be ready to accept the code.
A.R.S., November 2012
